Java/Data Type/Number Format

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Содержание

A custom number formatter that formats numbers as hexadecimal strings.

   <source lang="java">

/* 

* JFreeChart : a free chart library for the Java(tm) platform
* 
*
* (C) Copyright 2000-2008, by Object Refinery Limited and Contributors.
*
* Project Info:  http://www.jfree.org/jfreechart/index.html
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
* USA.
*
* [Java is a trademark or registered trademark of Sun Microsystems, Inc.
* in the United States and other countries.]
*
* --------------------
* HexNumberFormat.java
* --------------------
* (C) Copyright 2007, 2008, by Richard West and Contributors.
*
* Original Author:  Richard West, Advanced Micro Devices, Inc.;
* Contributor(s):   David Gilbert (for Object Refinery Limited);
*
* Changes:
* --------
* 14-Jun-2007 : Version 1 (RW);
*
*/

import java.text.FieldPosition; import java.text.NumberFormat; import java.text.ParsePosition; /** 

* A custom number formatter that formats numbers as hexadecimal strings.
* There are some limitations, so be careful using this class.
*
* @since 1.0.6
*/

public class HexNumberFormat extends NumberFormat { 

   /** Number of hexadecimal digits for a byte. */
   public static final int BYTE = 2;
   /** Number of hexadecimal digits for a word. */
   public static final int WORD = 4;
   /** Number of hexadecimal digits for a double word. */
   public static final int DWORD = 8;
   /** Number of hexadecimal digits for a quad word. */
   public static final int QWORD = 16;
   /** The number of digits (shorter strings will be left padded). */
   private int m_numDigits = DWORD;
   /**
    * Creates a new instance with 8 digits.
    */
   public HexNumberFormat() {
       this(DWORD);
   }
   /**
    * Creates a new instance with the specified number of digits.
    * @param digits  the digits.
    */
   public HexNumberFormat(int digits) {
       super();
       this.m_numDigits = digits;
   }
   /**
    * Returns the number of digits.
    *
    * @return The number of digits.
    */
   public final int getNumberOfDigits() {
       return this.m_numDigits;
   }
   /**
    * Sets the number of digits.
    *
    * @param digits  the number of digits.
    */
   public void setNumberOfDigits(int digits) {
       this.m_numDigits = digits;
   }
   /**
    * Formats the specified number as a hexadecimal string.  The decimal
    * fraction is ignored.
    *
    * @param number  the number to format.
    * @param toAppendTo  the buffer to append to (ignored here).
    * @param pos  the field position (ignored here).
    *
    * @return The string buffer.
    */
   public StringBuffer format(double number, StringBuffer toAppendTo,
           FieldPosition pos) {
       return format((long) number, toAppendTo, pos);
   }
   /**
    * Formats the specified number as a hexadecimal string.  The decimal
    * fraction is ignored.
    *
    * @param number  the number to format.
    * @param toAppendTo  the buffer to append to (ignored here).
    * @param pos  the field position (ignored here).
    *
    * @return The string buffer.
    */
   public StringBuffer format(long number, StringBuffer toAppendTo,
           FieldPosition pos) {
       String l_hex = Long.toHexString(number).toUpperCase();
       int l_pad = this.m_numDigits - l_hex.length();
       l_pad = (0 < l_pad) ? l_pad : 0;
       StringBuffer l_extended = new StringBuffer("0x");
       for (int i = 0; i < l_pad; i++) {
           l_extended.append(0);
       }
       l_extended.append(l_hex);
       return l_extended;
   }
   /**
    * Parsing is not implemented, so this method always returns
    * null.
    *
    * @param source  ignored.
    * @param parsePosition  ignored.
    *
    * @return Always null.
    */
   public Number parse (String source, ParsePosition parsePosition) {
       return null; // don"t bother with parsing
   }

} 



 </source>



Add leading zeroes to a number

   <source lang="java">

public class Main { 

 public static void main(String[] args) {
   int number = 1500;
   String formatted = String.format("%07d", number);
   System.out.println("Number with leading zeros: " + formatted);
 }

} 



 </source>



A number formatter for logarithmic values. This formatter does not support parsing.

   <source lang="java">

/* 

* JFreeChart : a free chart library for the Java(tm) platform
* 
*
* (C) Copyright 2000-2009, by Object Refinery Limited and Contributors.
*
* Project Info:  http://www.jfree.org/jfreechart/index.html
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
* USA.
*
* [Java is a trademark or registered trademark of Sun Microsystems, Inc.
* in the United States and other countries.]
*
* --------------
* LogFormat.java
* --------------
* (C) Copyright 2007-2009, by Object Refinery Limited and Contributors.
*
* Original Author:  David Gilbert (for Object Refinery Limited);
* Contributor(s):   -;
*
* Changes
* -------
* 02-Aug-2007 : Version 1 (DG);
* 19-Feb-2008 : Implemented equals() and clone(), and added new powerLabel
*               attribute as per Feature Request 1886036 (DG);
* 14-Jan-2009 : Added default constructor, and accessor methods for
*               exponent formatter (DG);
*
*/

import java.text.DecimalFormat; import java.text.FieldPosition; import java.text.NumberFormat; import java.text.ParsePosition; /** 

* A number formatter for logarithmic values.  This formatter does not support
* parsing.
*
* @since 1.0.7
*/

public class LogFormat extends NumberFormat { 

   /** The log base value. */
   private double base;
   /** The natural logarithm of the base value. */
   private double baseLog;
   /** The label for the log base (for example, "e"). */
   private String baseLabel;
   /**
    * The label for the power symbol.
    *
    * @since 1.0.10
    */
   private String powerLabel;
   /** A flag that controls whether or not the base is shown. */
   private boolean showBase;
   /** The number formatter for the exponent. */
   private NumberFormat formatter = new DecimalFormat("0.0#");
   /**
    * Creates a new instance using base 10.
    *
    * @since 1.0.13
    */
   public LogFormat() {
       this(10.0, "10", true);
   }
   /**
    * Creates a new instance.
    *
    * @param base  the base.
    * @param baseLabel  the base label (null not permitted).
    * @param showBase  a flag that controls whether or not the base value is
    *                  shown.
    */
   public LogFormat(double base, String baseLabel, boolean showBase) {
       this(base, baseLabel, "^", showBase);
   }
   /**
    * Creates a new instance.
    *
    * @param base  the base.
    * @param baseLabel  the base label (null not permitted).
    * @param powerLabel  the power label (null not permitted).
    * @param showBase  a flag that controls whether or not the base value is
    *                  shown.
    *
    * @since 1.0.10
    */
   public LogFormat(double base, String baseLabel, String powerLabel,
           boolean showBase) {
       if (baseLabel == null) {
           throw new IllegalArgumentException("Null "baseLabel" argument.");
       }
       if (powerLabel == null) {
           throw new IllegalArgumentException("Null "powerLabel" argument.");
       }
       this.base = base;
       this.baseLog = Math.log(this.base);
       this.baseLabel = baseLabel;
       this.showBase = showBase;
       this.powerLabel = powerLabel;
   }
   /**
    * Returns the number format used for the exponent.
    *
    * @return The number format (never null).
    *
    * @since 1.0.13.
    */
   public NumberFormat getExponentFormat() {
       return (NumberFormat) this.formatter.clone();
   }
   /**
    * Sets the number format used for the exponent.
    *
    * @param format  the formatter (null not permitted).
    *
    * @since 1.0.13
    */
   public void setExponentFormat(NumberFormat format) {
       if (format == null) {
           throw new IllegalArgumentException("Null "format" argument.");
       }
       this.formatter = format;
   }
   /**
    * Calculates the log of a given value.
    *
    * @param value  the value.
    *
    * @return The log of the value.
    */
   private double calculateLog(double value) {
       return Math.log(value) / this.baseLog;
   }
   /**
    * Returns a formatted representation of the specified number.
    *
    * @param number  the number.
    * @param toAppendTo  the string buffer to append to.
    * @param pos  the position.
    *
    * @return A string buffer containing the formatted value.
    */
   public StringBuffer format(double number, StringBuffer toAppendTo,
           FieldPosition pos) {
       StringBuffer result = new StringBuffer();
       if (this.showBase) {
           result.append(this.baseLabel);
           result.append(this.powerLabel);
       }
       result.append(this.formatter.format(calculateLog(number)));
       return result;
   }
   /**
    * Formats the specified number as a hexadecimal string.  The decimal
    * fraction is ignored.
    *
    * @param number  the number to format.
    * @param toAppendTo  the buffer to append to (ignored here).
    * @param pos  the field position (ignored here).
    *
    * @return The string buffer.
    */
   public StringBuffer format(long number, StringBuffer toAppendTo,
           FieldPosition pos) {
       StringBuffer result = new StringBuffer();
       if (this.showBase) {
           result.append(this.baseLabel);
           result.append("^");
       }
       result.append(this.formatter.format(calculateLog(number)));
       return result;
   }
   /**
    * Parsing is not implemented, so this method always returns
    * null.
    *
    * @param source  ignored.
    * @param parsePosition  ignored.
    *
    * @return Always null.
    */
   public Number parse (String source, ParsePosition parsePosition) {
       return null; // don"t bother with parsing
   }
   /**
    * Tests this formatter for equality with an arbitrary object.
    *
    * @param obj  the object (null permitted).
    *
    * @return A boolean.
    */
   public boolean equals(Object obj) {
       if (obj == this) {
           return true;
       }
       if (!(obj instanceof LogFormat)) {
           return false;
       }
       LogFormat that = (LogFormat) obj;
       if (this.base != that.base) {
           return false;
       }
       if (!this.baseLabel.equals(that.baseLabel)) {
           return false;
       }
       if (this.baseLog != that.baseLog) {
           return false;
       }
       if (this.showBase != that.showBase) {
           return false;
       }
       if (!this.formatter.equals(that.formatter)) {
           return false;
       }
       return super.equals(obj);
   }
   /**
    * Returns a clone of this instance.
    *
    * @return A clone.
    */
   public Object clone() {
       LogFormat clone = (LogFormat) super.clone();
       clone.formatter = (NumberFormat) this.formatter.clone();
       return clone;
   }

} 



 </source>



Create a table of squares and cubes.

   <source lang="java">

import java.util.Formatter; class FieldWidthDemo { 

 public static void main(String args[]) {
   Formatter fmt;
   for (int i = 1; i <= 10; i++) {
     fmt = new Formatter();
     fmt.format("%4d %4d %4d", i, i * i, i * i * i);
     System.out.println(fmt);
   }
 }

} 



 </source>



Decimal Format Demo

   <source lang="java">

/* 

* Copyright (c) 1995 - 2008 Sun Microsystems, Inc.  All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
*   - Redistributions of source code must retain the above copyright
*     notice, this list of conditions and the following disclaimer.
*
*   - Redistributions in binary form must reproduce the above copyright
*     notice, this list of conditions and the following disclaimer in the
*     documentation and/or other materials provided with the distribution.
*
*   - Neither the name of Sun Microsystems nor the names of its
*     contributors may be used to endorse or promote products derived
*     from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

import java.awt.Color; import java.awt.ruponent; import java.awt.GridLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import java.awt.event.WindowListener; import java.text.DecimalFormat; import java.text.NumberFormat; import java.text.ParseException; import java.util.Locale; import javax.swing.BorderFactory; import javax.swing.Box; import javax.swing.BoxLayout; import javax.swing.JComboBox; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; import javax.swing.JTextField; public class DecimalFormatDemo extends JPanel { 

 static JFrame frame;
 JLabel result;
 NumberFormat inputFormatter;
 String currentPattern;
 double currentNumber = 123.45;
 LocaleGroup availableLocales;
 public DecimalFormatDemo() {
   availableLocales = new LocaleGroup();
   inputFormatter = NumberFormat.getNumberInstance();
   String[] patternExamples = { "##.##", "###,###.##", "##,##,##.##", "#",
       "000,000.0000", "##.0000", ""hello"###.##" };
   currentPattern = patternExamples[0];
   // Set up the UI for entering a number.
   JLabel numberLabel = new JLabel("Enter the number to format:");
   numberLabel.setAlignmentX(Component.LEFT_ALIGNMENT);
   JTextField numberField = new JTextField();
   numberField.setEditable(true);
   numberField.setAlignmentX(Component.LEFT_ALIGNMENT);
   NumberListener numberListener = new NumberListener();
   numberField.addActionListener(numberListener);
   // Set up the UI for selecting a pattern.
   JLabel patternLabel1 = new JLabel("Enter the pattern string or");
   JLabel patternLabel2 = new JLabel("select one from the list:");
   patternLabel1.setAlignmentX(Component.LEFT_ALIGNMENT);
   patternLabel2.setAlignmentX(Component.LEFT_ALIGNMENT);
   JComboBox patternList = new JComboBox(patternExamples);
   patternList.setSelectedIndex(0);
   patternList.setEditable(true);
   patternList.setAlignmentX(Component.LEFT_ALIGNMENT);
   PatternListener patternListener = new PatternListener();
   patternList.addActionListener(patternListener);
   // Set up the UI for selecting a locale.
   JLabel localeLabel = new JLabel("Select a Locale from the list:");
   localeLabel.setAlignmentX(Component.LEFT_ALIGNMENT);
   JComboBox localeList = new JComboBox(availableLocales.getStrings());
   localeList.setSelectedIndex(0);
   localeList.setAlignmentX(Component.LEFT_ALIGNMENT);
   LocaleListener localeListener = new LocaleListener();
   localeList.addActionListener(localeListener);
   // Create the UI for displaying result.
   JLabel resultLabel = new JLabel("Result", JLabel.LEFT);
   resultLabel.setAlignmentX(Component.LEFT_ALIGNMENT);
   result = new JLabel(" ");
   result.setForeground(Color.black);
   result.setAlignmentX(Component.LEFT_ALIGNMENT);
   result.setBorder(BorderFactory.createCompoundBorder(BorderFactory
       .createLineBorder(Color.black), BorderFactory.createEmptyBorder(5, 5,
       5, 5)));
   // Lay out everything
   JPanel numberPanel = new JPanel();
   numberPanel.setLayout(new GridLayout(0, 1));
   numberPanel.add(numberLabel);
   numberPanel.add(numberField);
   JPanel patternPanel = new JPanel();
   patternPanel.setLayout(new BoxLayout(patternPanel, BoxLayout.Y_AXIS));
   patternPanel.add(patternLabel1);
   patternPanel.add(patternLabel2);
   patternPanel.add(patternList);
   JPanel localePanel = new JPanel();
   localePanel.setLayout(new BoxLayout(localePanel, BoxLayout.Y_AXIS));
   localePanel.add(localeLabel);
   localePanel.add(localeList);
   JPanel resultPanel = new JPanel();
   resultPanel.setLayout(new GridLayout(0, 1));
   resultPanel.add(resultLabel);
   resultPanel.add(result);
   setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));
   patternPanel.setAlignmentX(Component.CENTER_ALIGNMENT);
   numberPanel.setAlignmentX(Component.CENTER_ALIGNMENT);
   localePanel.setAlignmentX(Component.CENTER_ALIGNMENT);
   resultPanel.setAlignmentX(Component.CENTER_ALIGNMENT);
   add(numberPanel);
   add(Box.createVerticalStrut(10));
   add(patternPanel);
   add(Box.createVerticalStrut(10));
   add(localePanel);
   add(Box.createVerticalStrut(10));
   add(resultPanel);
   setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
   reformat();
   numberField.setText(result.getText());
 } // constructor
 /** Listens to the pattern combo box. */
 class PatternListener implements ActionListener {
   public void actionPerformed(ActionEvent e) {
     JComboBox cb = (JComboBox) e.getSource();
     String newSelection = (String) cb.getSelectedItem();
     currentPattern = newSelection;
     reformat();
   }
 }
 /** Listens to the number field. */
 class NumberListener implements ActionListener {
   public void actionPerformed(ActionEvent evt) {
     JTextField inputField = (JTextField) evt.getSource();
     try {
       Number value = inputFormatter.parse(inputField.getText());
       currentNumber = value.doubleValue();
       reformat();
     } catch (ParseException pe) {
       result.setForeground(Color.red);
       result.setText("Illegal Number: " + pe.getMessage());
     }
   }
 }
 /** Listens to the locale combo box. */
 class LocaleListener implements ActionListener {
   public void actionPerformed(ActionEvent e) {
     JComboBox cb = (JComboBox) e.getSource();
     int index = cb.getSelectedIndex();
     availableLocales.setCurrent(index);
     reformat();
   }
 }
 /** Manages information about locales for this application. */
 class LocaleGroup {
   Locale currentLocale;
   Locale[] supportedLocales = { Locale.US, Locale.GERMANY, Locale.FRANCE
   // Add other locales here, if desired.
   };
   public LocaleGroup() {
     currentLocale = supportedLocales[0];
   }
   public void setCurrent(int index) {
     currentLocale = supportedLocales[index];
   }
   public Locale getCurrent() {
     return currentLocale;
   }
   public String[] getStrings() {
     String[] localeNames = new String[supportedLocales.length];
     for (int k = 0; k < supportedLocales.length; k++) {
       localeNames[k] = supportedLocales[k].getDisplayName();
     }
     return localeNames;
   }
 }
 /** Reformats the input number and displays result. */
 public void reformat() {
   try {
     NumberFormat nf = NumberFormat.getNumberInstance(availableLocales
         .getCurrent());
     DecimalFormat df = (DecimalFormat) nf;
     df.applyPattern(currentPattern);
     result.setForeground(Color.black);
     result.setText(df.format(currentNumber));
   } catch (IllegalArgumentException iae) {
     result.setForeground(Color.red);
     result.setText("Illegal Pattern: " + iae.getMessage());
   }
 }
 public static void main(String s[]) {
   WindowListener l = new WindowAdapter() {
     public void windowClosing(WindowEvent e) {
       System.exit(0);
     }
   };
   frame = new JFrame("DecimalFormat Demo");
   frame.addWindowListener(l);
   frame.getContentPane().add("Center", new DecimalFormatDemo());
   frame.pack();
   frame.setVisible(true);
 }

} 



 </source>



Default rounding mode

   <source lang="java">

import java.math.RoundingMode; import java.text.NumberFormat; public class NumberFormatRounding { 

 public static void main(String[] args) {
   NumberFormat nf = NumberFormat.getNumberInstance();
   nf.setMaximumFractionDigits(2);
   System.out.println("Default rounding mode: " + nf.getRoundingMode());
   System.out.println("123.454 rounds to " + nf.format(123.454));
   System.out.println("123.455 rounds to " + nf.format(123.455));
   System.out.println("123.456 rounds to " + nf.format(123.456));
   System.out.println();
 }

} 



 </source>



demonstrates the minimum field-width specifier by applying it to the %f conversion:

   <source lang="java">

// Demonstrate a field-width specifier. import java.util.Formatter; class FormatDemo4 { 

 public static void main(String args[]) {
   Formatter fmt = new Formatter();
   fmt.format("|%f|%n|%12f|%n|%012f|", 10.12345, 10.12345, 10.12345);
   System.out.println(fmt);
 }

} 



 </source>



demonstrates the %n and %% format specifiers:

   <source lang="java">

import java.util.Formatter; class FormatDemo3 { 

 public static void main(String args[]) {
   Formatter fmt = new Formatter();
   fmt.format("Copying file%nTransfer is %d%% complete", 88);
   System.out.println(fmt);
 }

} 



 </source>



Demonstrate the space format specifiers.

   <source lang="java">

import java.util.Formatter; public class MainClass { 

 public static void main(String args[]) {
   Formatter fmt = new Formatter();
   fmt.format("% d", -100);
   System.out.println(fmt);
   fmt = new Formatter();
   fmt.format("% d", 100);
   System.out.println(fmt);
   fmt = new Formatter();
   fmt.format("% d", -200);
   System.out.println(fmt);
   fmt = new Formatter();
   fmt.format("% d", 200);
   System.out.println(fmt);
 }

} /* -100 

100

-200 

200*/
  
   
   
   
 </source>



Displaying numbers with commas

   <source lang="java">

import java.text.DecimalFormat; public class Main { 

 public static void main(String args[]) {
   double d = 123456.78;
   DecimalFormat df = new DecimalFormat("#####0.00");
   System.out.println(df.format(d));
 }

} 


 </source>



Display numbers in scientific notation

   <source lang="java">

import java.text.DecimalFormat; import java.text.NumberFormat; public class Main { 

 public static void main(String args[]) {
   NumberFormat formatter = new DecimalFormat();
   int maxinteger = Integer.MAX_VALUE;
   System.out.println(maxinteger); 
   formatter = new DecimalFormat("0.######E0");
   System.out.println(formatter.format(maxinteger));
   formatter = new DecimalFormat("0.#####E0");
   System.out.println(formatter.format(maxinteger));
   int mininteger = Integer.MIN_VALUE;
   System.out.println(mininteger); 
   formatter = new DecimalFormat("0.######E0");
   System.out.println(formatter.format(mininteger)); 
   formatter = new DecimalFormat("0.#####E0");
   System.out.println(formatter.format(mininteger));
   double d = 0.12345;
   formatter = new DecimalFormat("0.#####E0");
   System.out.println(formatter.format(d));
   formatter = new DecimalFormat("000000E0");
   System.out.println(formatter.format(d)); 
 }

} 


 </source>



Format a number for a locale

   <source lang="java">

import java.text.NumberFormat; import java.util.Locale; public class Main { 

 public static void main(String[] args) throws Exception {
   NumberFormat formatter = NumberFormat.getNumberInstance(Locale.ITALY);
   String number = formatter.format(123456789.12);
   System.out.println("Number in Italy: " + number);
   formatter = NumberFormat.getNumberInstance(Locale.JAPAN);
   number = formatter.format(123456789.12);
   System.out.println("Number in Japan: " + number);
 }

} 



 </source>



Format a number our way and the default way

   <source lang="java">

import java.text.NumberFormat; /* 

* Format a number our way and the default way.
*/

public class NumFormat2 { 

 /** A number to format */
 public static final double data[] = {
   0, 1, 22d/7, 100.2345678
 };
 /** The main (and only) method in this class. */
 public static void main(String[] av) { 
   // Get a format instance
   NumberFormat form = NumberFormat.getInstance();
   // Set it to look like 999.99[99]
   form.setMinimumIntegerDigits(3);
   form.setMinimumFractionDigits(2);
   form.setMaximumFractionDigits(4);
   // Now print using it.
   for (int i=0; i<data.length; i++)
     System.out.println(data[i] + "\tformats as " +
       form.format(data[i]));
 }

} 



 </source>



Format a number to currency

   <source lang="java">

import java.text.NumberFormat; public class Mortgage { 

 public static void main(String[] args) {
   double payment = Math.random() * 1000;
   System.out.println("Your payment is ");
   NumberFormat nf = NumberFormat.getCurrencyInstance();
   System.out.println(nf.format(payment));
 }

} 



 </source>



Format a number with DecimalFormat

   <source lang="java">

import java.text.DecimalFormat; import java.text.NumberFormat; public class Main { 

 public static void main(String[] args) {
   double money = 123456789.12;
   NumberFormat formatter = new DecimalFormat("#0.00");
   System.out.println(money);
   System.out.println(formatter.format(money));
 }

} 


 </source>



Format a number with leading zeroes

   <source lang="java">

import java.text.DecimalFormat; import java.text.NumberFormat; public class Main { 

 public static void main(String[] args) {
   NumberFormat formatter = new DecimalFormat("0000000");
   String number = formatter.format(2500);
   System.out.println("Number with lading zeros: " + number);
 }

} 



 </source>



Format for GERMAN locale

   <source lang="java">

import java.text.NumberFormat; import java.util.Locale; public class Main { 

 public static void main(String[] argv) throws Exception {
   Locale locale = Locale.GERMAN;
   String string = NumberFormat.getNumberInstance(locale).format(-1234.56); 
   System.out.println(string);
 }

} //-1.234,56 


 </source>



Format for the default locale

   <source lang="java">

import java.text.NumberFormat; public class Main { 

 public static void main(String[] argv) throws Exception {
   String string = NumberFormat.getNumberInstance().format(-1234.56);
   System.out.println(string);
 }

} //-1,234.56 


 </source>



Formatting and Parsing a Locale-Specific Percentage

   <source lang="java">

import java.text.NumberFormat; import java.util.Locale; public class Main { 

 public static void main(String[] argv) throws Exception {
   // Format
   Locale locale = Locale.CANADA;
   String string = NumberFormat.getPercentInstance(locale).format(123.45);
 }

} // 12,345% 


 </source>



Formatting and Parsing a Number for a Locale

   <source lang="java">

Format for CANADA locale import java.text.NumberFormat; import java.util.Locale; public class Main { 

 public static void main(String[] argv) throws Exception {
   Locale locale = Locale.CANADA;
   String string = NumberFormat.getNumberInstance(locale).format(-1234.56); 
   System.out.println(string);
 }

} //-1,234.56 


 </source>



Formatting and Parsing Locale-Specific Currency

   <source lang="java">

import java.text.NumberFormat; import java.util.Locale; public class Main { 

 public static void main(String[] argv) throws Exception {
   // Format
   Locale locale = Locale.GERMANY;
   String string = NumberFormat.getCurrencyInstance(locale).format(123.45);
 }

} // 123,45 DM 


 </source>



Formatting a Number in Exponential Notation

   <source lang="java">

The "E" symbol specifies that a number should be formatted in exponential notation. E symbol separates the mantissa from the exponent. E symbol must be followed by one or more "0" symbols. The number of "0" symbols specifies the minimum number of digits used to display the exponent. 


 </source>



left justification: left justify

   <source lang="java">

import java.util.Formatter; public class MainClass { 

 public static void main(String args[]) {
   Formatter fmt = new Formatter();
   fmt.format("|%-10.2f|", 123.123);
   System.out.println(fmt);
 }

} //|123.12 | 



 </source>



left justification: Right justify by default

   <source lang="java">

import java.util.Formatter; public class MainClass { 

 public static void main(String args[]) {
   Formatter fmt = new Formatter();
   fmt.format("|%10.2f|", 123.123);
   System.out.println(fmt);
 }

} //| 123.12| 



 </source>



NumberFormat and locale

   <source lang="java">

import java.text.NumberFormat; import java.util.Locale; public class Main { 

 public static void main(String[] args) {
   double value = 1234567.89;
   System.out.println("Unformatted: " + value + "\n");
   Locale locales[] = { Locale.US, Locale.FRANCE, Locale.GERMANY, Locale.JAPAN,
       new Locale("fr", "FR", "EURO"), new Locale("de", "DE", "EURO") };
   for (int i = 0; i < locales.length; i++) {
     NumberFormat nf = NumberFormat.getCurrencyInstance(locales[i]);
     System.out.println("Formatted for " + locales[i] + ": " + nf.format(value));
   }
 }

} 


 </source>



Number Format by locale

   <source lang="java">

import java.text.NumberFormat; import java.util.Locale; class NumberFormatApp { 

 public static void main(String args[]) {
   NumberFormat format = NumberFormat.getCurrencyInstance(Locale.getDefault());
   String formattedCurrency = format.format(1000000);
   System.out.println(formattedCurrency);
 }

} 



 </source>



Number format viewer

   <source lang="java">

import java.text.NumberFormat; import java.util.Locale; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JScrollPane; import javax.swing.JTable; import javax.swing.table.AbstractTableModel; public class NumberViewer extends JPanel { 

 protected AbstractTableModel tableModel;
 protected double currentValue = 1234567.89d;
 protected final static Locale[] availableLocales;
 static {
   availableLocales = Locale.getAvailableLocales();
 }
 public final static int LOCALE_COLUMN = 0;
 public final static int NUMBER_COLUMN = 1;
 public final static int CURRENCY_COLUMN = 2;
 public final static int PERCENT_COLUMN = 3;
 public final static String[] columnHeaders = { "Locale", "Numeric", "Currency", "Percent" };
 public static void main(String[] args) {
   JFrame f = new JFrame("Number Viewer");
   f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
   f.getContentPane().add(new NumberViewer());
   f.pack();
   f.setVisible(true);
 }
 public NumberViewer() {
   tableModel = new LocaleTableModel();
   JTable table = new JTable(tableModel);
   add(new JScrollPane(table));
 }
 class LocaleTableModel extends AbstractTableModel {
   public int getRowCount() {
     return availableLocales.length;
   }
   public int getColumnCount() {
     return columnHeaders.length;
   }
   public Object getValueAt(int row, int column) {
     Locale locale = availableLocales[row];
     NumberFormat formatter = NumberFormat.getNumberInstance();
     switch (column) {
     case LOCALE_COLUMN:
       return locale.getDisplayName();
     case NUMBER_COLUMN:
       formatter = NumberFormat.getNumberInstance(locale);
       break;
     case CURRENCY_COLUMN:
       formatter = NumberFormat.getCurrencyInstance(locale);
       break;
     case PERCENT_COLUMN:
       formatter = NumberFormat.getPercentInstance(locale);
       break;
     }
     return formatter.format(currentValue);
   }
   public String getColumnName(int column) {
     return columnHeaders[column];
   }
 }

} 



 </source>



NumberFormat with Constant Locale Usage

   <source lang="java">

import java.text.NumberFormat; import java.text.ParseException; import java.util.Locale; public class ConstantLocaleUsage { 

 public static void main(String[] argv) {
   NumberFormat numberFormat = NumberFormat.getInstance();
   numberFormat.setParseIntegerOnly(false);
   double usersNumber;
   if (argv.length == 1)
     try {
       usersNumber = numberFormat.parse(argv[0]).doubleValue();
     } catch (ParseException e) {
       usersNumber = 197912.29;
     }
   else
     usersNumber = 1976.0826;
   numberFormat = NumberFormat.getNumberInstance(Locale.US);
   System.out.println("User"s number (US): "
       + numberFormat.format(usersNumber));
   numberFormat = NumberFormat.getNumberInstance(Locale.GERMANY);
   System.out.println("User"s number (GERMANY): "
       + numberFormat.format(usersNumber));
   numberFormat = NumberFormat.getNumberInstance();
   System.out.println("User"s number (DEFAULT LOCALE): "
       + numberFormat.format(usersNumber));
 }

} 



 </source>



Number Format with Locale

   <source lang="java">

/* 

* Copyright (c) 1995 - 2008 Sun Microsystems, Inc.  All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
*   - Redistributions of source code must retain the above copyright
*     notice, this list of conditions and the following disclaimer.
*
*   - Redistributions in binary form must reproduce the above copyright
*     notice, this list of conditions and the following disclaimer in the
*     documentation and/or other materials provided with the distribution.
*
*   - Neither the name of Sun Microsystems nor the names of its
*     contributors may be used to endorse or promote products derived
*     from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

import java.text.NumberFormat; import java.util.Locale; public class NumberFormatDemo { 

 static public void displayNumber(Locale currentLocale) {
   Integer quantity = new Integer(123456);
   Double amount = new Double(345987.246);
   NumberFormat numberFormatter;
   String quantityOut;
   String amountOut;
   numberFormatter = NumberFormat.getNumberInstance(currentLocale);
   quantityOut = numberFormatter.format(quantity);
   amountOut = numberFormatter.format(amount);
   System.out.println(quantityOut + "   " + currentLocale.toString());
   System.out.println(amountOut + "   " + currentLocale.toString());
 }
 static public void displayCurrency(Locale currentLocale) {
   Double currency = new Double(9876543.21);
   NumberFormat currencyFormatter;
   String currencyOut;
   currencyFormatter = NumberFormat.getCurrencyInstance(currentLocale);
   currencyOut = currencyFormatter.format(currency);
   System.out.println(currencyOut + "   " + currentLocale.toString());
 }
 static public void displayPercent(Locale currentLocale) {
   Double percent = new Double(0.75);
   NumberFormat percentFormatter;
   String percentOut;
   percentFormatter = NumberFormat.getPercentInstance(currentLocale);
   percentOut = percentFormatter.format(percent);
   System.out.println(percentOut + "   " + currentLocale.toString());
 }
 static public void main(String[] args) {
   Locale[] locales = { new Locale("fr", "FR"), new Locale("de", "DE"),
       new Locale("en", "US") };
   for (int i = 0; i < locales.length; i++) {
     System.out.println();
     displayNumber(locales[i]);
     displayCurrency(locales[i]);
     displayPercent(locales[i]);
   }
 }

} 



 </source>



Parse a GERMAN number

   <source lang="java">

import java.text.NumberFormat; import java.util.Locale; public class Main { 

 public static void main(String[] argv) throws Exception {
   Number number = NumberFormat.getNumberInstance(Locale.GERMAN).parse("-1.234,56");
   if (number instanceof Long) {
     System.out.println("Long value"); 
   } else {
     System.out.println("Double value"); 
   }
 }

} 


 </source>



Parse a number for a locale

   <source lang="java">

import java.text.NumberFormat; import java.util.Locale; public class Main { 

 public static void main(String[] args) throws Exception {
   Number number = NumberFormat.getNumberInstance(Locale.JAPAN).parse("25,000.75");
   if (number instanceof Long) {
     System.out.println("Long value: " + number.longValue());
   } else if (number instanceof Double) {
     System.out.println("Double value: " + number.doubleValue());
   }
 }

} 


 </source>



Parse a number with NumberFormat and Locale.CANADA

   <source lang="java">

import java.text.NumberFormat; import java.util.Locale; public class Main { 

 public static void main(String[] argv) throws Exception {
   Number number = NumberFormat.getPercentInstance(Locale.CANADA).parse("123.45%");
   // 1.2345
   if (number instanceof Long) {
     System.out.println("Long value");
   } else {
     System.out.println("Double value");
   }
 }

} 


 </source>



Parse number with NumberFormat and Locale

   <source lang="java">

import java.text.NumberFormat; import java.util.Locale; public class Main { 

 public static void main(String[] argv) throws Exception {
   Number number = NumberFormat.getCurrencyInstance(Locale.GERMANY).parse("$123.45");
   if (number instanceof Long) {
     System.out.println("Long value");
   } else {
     System.out.println("Double value");
   }
 }

} 


 </source>



precision modifier: Display at most 15 characters in a string

   <source lang="java">

import java.util.Formatter; public class MainClass { 

 public static void main(String args[]) {
   Formatter fmt = new Formatter();
   fmt.format("%.15s", "Formatting with Java is now easy.");
   System.out.println(fmt);
 }

} //Formatting with 



 </source>



precision modifier: Format 4 decimal places

   <source lang="java">

import java.util.Formatter; public class MainClass { 

 public static void main(String args[]) {
   Formatter fmt = new Formatter();
   fmt.format("%.4f", 123.1234567);
   System.out.println(fmt);
 }

} //123.1235 



 </source>



precision modifier: Format to 2 decimal places in a 16 character field

   <source lang="java">

import java.util.Formatter; public class MainClass { 

 public static void main(String args[]) {
   Formatter fmt = new Formatter();
   // Format 4 decimal places.
   fmt = new Formatter();
   fmt.format("%16.2e", 123.1234567);
   System.out.println(fmt);
 }

} // 1.23e+02 



 </source>



RoundingMode.CEILING

   <source lang="java">

import java.math.RoundingMode; import java.text.NumberFormat; public class NumberFormatRounding { 

 public static void main(String[] args) {
   NumberFormat nf = NumberFormat.getNumberInstance();
   nf.setMaximumFractionDigits(2);
   nf.setRoundingMode (RoundingMode.CEILING);
   System.out.println("Default rounding mode: " + nf.getRoundingMode());
   System.out.println("123.454 rounds to " + nf.format(123.454));
   System.out.println("123.455 rounds to " + nf.format(123.455));
   System.out.println("123.456 rounds to " + nf.format(123.456));
   System.out.println();
 }

} 



 </source>



RoundingMode.FLOOR

   <source lang="java">

import java.math.RoundingMode; import java.text.NumberFormat; public class NumberFormatRounding { 

 public static void main(String[] args) {
   NumberFormat nf = NumberFormat.getNumberInstance();
   nf.setMaximumFractionDigits(2);
   nf.setRoundingMode (RoundingMode.FLOOR);
   System.out.println("Default rounding mode: " + nf.getRoundingMode());
   System.out.println("123.454 rounds to " + nf.format(123.454));
   System.out.println("123.455 rounds to " + nf.format(123.455));
   System.out.println("123.456 rounds to " + nf.format(123.456));
   System.out.println();
 }

} 



 </source>



RoundingMode.HALF_DOWN

   <source lang="java">

import java.math.RoundingMode; import java.text.NumberFormat; public class NumberFormatRounding { 

 public static void main(String[] args) {
   NumberFormat nf = NumberFormat.getNumberInstance();
   nf.setMaximumFractionDigits(2);
   nf.setRoundingMode (RoundingMode.HALF_DOWN);
   System.out.println("Default rounding mode: " + nf.getRoundingMode());
   System.out.println("123.454 rounds to " + nf.format(123.454));
   System.out.println("123.455 rounds to " + nf.format(123.455));
   System.out.println("123.456 rounds to " + nf.format(123.456));
   System.out.println();
 }

} 



 </source>



The Format Specifiers

   <source lang="java">

Format Specifier Conversion Applied %a Floating-point hexadecimal %A %b Boolean %B %c Character %C %d Decimal integer %h Hash code of the argument %H %e Scientific notation %E %f Decimal floating-point %g Uses %e or %f, whichever is shorter %G %o Octal integer %n Inserts a newline character %s String %S %t Time and date %T %x Integer hexadecimal %X %% Inserts a % sign 



 </source>



the NumberFormat object is created once when the program starts.

   <source lang="java">

import java.text.NumberFormat; public class MainClass { 

 static NumberFormat cf = NumberFormat.getCurrencyInstance();
 public static void main(String[] args) {
   printMyAllowance();
   printCostOfPaintBallGun();
 }
 public static void printMyAllowance() {
   double myAllowance = 5.00;
   cf = NumberFormat.getCurrencyInstance();
   System.out.println("My allowance: " + cf.format(myAllowance));
 }
 public static void printCostOfPaintBallGun() {
   double costOfPaintBallGun = 69.95;
   cf = NumberFormat.getCurrencyInstance();
   System.out.println("Cost of Paint Ball Gun: " + cf.format(costOfPaintBallGun));
 }

} 



 </source>



The Uppercase Option

   <source lang="java">

Specifier Effect %A Causes the hexadecimal digits a through f to be displayed in uppercase as A through F. Also, the prefix 0x is displayed as 0X, and the p will be displayed as P. %B Uppercases the values true and false. %C Uppercases the corresponding character argument. %E Causes the e symbol that indicates the exponent to be displayed in uppercase. %G Causes the e symbol that indicates the exponent to be displayed in uppercase. %H Causes the hexadecimal digits a through f to be displayed in uppercase as A through F. %S Uppercases the corresponding string. %T Causes all alphabetical output to be displayed in uppercase. %X Causes the hexadecimal digits a through f to be displayed in uppercase as A through F. Also, the optional prefix 0x is displayed as 0X, if present. 



 </source>



Use grouping to display a number

   <source lang="java">

import java.text.NumberFormat; public class Main { 

 public static void main(String args[]) {
   NumberFormat nf = NumberFormat.getInstance();
   System.out.println("Default format: " + nf.format(1234567.678));
   nf.setGroupingUsed(false);
   System.out.println("Format without groupings: " + nf.format(1234567.678));
 }

} /* Default format: 1,234,567.678 Format without groupings: 1234567.678

  • /


 </source>



Using an Argument Index

   <source lang="java">

import java.util.Formatter; public class MainClass { 

 public static void main(String args[]) {
   Formatter fmt = new Formatter();
   fmt.format("%3$d %1$d %2$d", 10, 20, 30);
   System.out.println(fmt);
 }

} //30 10 20 



 </source>



Using only 0"s to the left of E forces no decimal point

   <source lang="java">

import java.text.DecimalFormat; import java.text.NumberFormat; public class Main { 

 public static void main(String[] argv) throws Exception {
   NumberFormat formatter = new DecimalFormat("0E0");
   String s = formatter.format(-1234.567);
   System.out.println(s);
 }

} // -1E3 


 </source>



Using the Format Flags

   <source lang="java">

Flag Effect - Left justification

  1. Alternate conversion format

0 Output is padded with zeros rather than spaces space Positive numeric output is preceded by a space + Positive numeric output is preceded by a + sign , Numeric values include grouping separators ( Negative numeric values are enclosed within parentheses 



 </source>
Источник — «http://www.jexp.ru/index.php?title=Java/Data_Type/Number_Format&oldid=6785»