Java Tutorial/JSP/Methods
Содержание
Creating a Method
<source lang="java">
<HTML>
<HEAD> <TITLE>Creating a Method</TITLE> </HEAD> <BODY>
Creating a Method
<%! int addem(int op1, int op2) { return op1 + op2; } %> <% out.println("2 + 2 = " + addem(2, 2)); %> </BODY>
</HTML></source>
Declaring Multiple Methods
<source lang="java">
<HTML>
<HEAD> <TITLE>Declaring Multiple Methods</TITLE> </HEAD> <BODY>
Declaring Multiple Methods
<%! int addem(int op1, int op2) { return op1 + op2; } int subtractem(int op1, int op2) { return op1 - op2; } %> <% out.println("2 + 2 = " + addem(2, 2) + "
"); out.println("8 - 2 = " + subtractem(8, 2) + "
"); %> </BODY>
</HTML></source>
Define function before HTML page
<source lang="java">
<%@ page language="java" contentType="text/html" %> <%@ page import="java.util.Date" %> <%!
private String getGreeting() { Date now = new Date(); String greeting = null; if (now.getHours() < 12) { greeting = "Good morning"; } else if (now.getHours() < 18) { greeting = "Good day"; } else { greeting = "Good evening"; } return greeting; }
%> <html>
<head> <title>All Scripting Elements</title> </head> <body bgcolor="white"> <%= getGreeting() %> <% if (request.getParameter("name") == null) { %> stranger! <% } else { %> partner! <% } %> How are you? </body>
</html></source>
Passing Arrays to Methods
<source lang="java">
<HTML>
<HEAD> <TITLE>Passing Arrays to Methods</TITLE> </HEAD> <BODY>
Passing Arrays to Methods
<%! void doubler(int a[]) { for (int i = 0; i < a.length;i++) { a[i] *= 2; } } %> <% int array[] = {1, 2, 3, 4, 5}; out.println("Before the call to doubler...
"); for (int i = 0; i < array.length;i++) { out.println("array[" + i + "] = " + array[i] + "
"); } doubler(array); out.println("After the call to doubler...
"); for (int i = 0; i < array.length; i++) { out.println("array[" + i + "] = " + array[i] + "
"); } %> </BODY>
</HTML></source>
Passing the out Object to a Method
<source lang="java">
<HTML>
<HEAD> <TITLE>Passing the out Object to a Method</TITLE> </HEAD> <BODY>
Passing the out Object to a Method
<%! void printem(javax.servlet.jsp.JspWriter out) throws java.io.IOException { out.println("Hello from JSP!"); } %> <% printem(out); %> </BODY>
</HTML></source>
Use page level function
<source lang="java">
<%@ page language="java" contentType="text/html" %> <%!
String randomColor() { java.util.Random random = new java.util.Random(); int red = (int) (random.nextFloat() * 255); int green = (int) (random.nextFloat() * 255); int blue = (int) (random.nextFloat() * 255); return "#" + Integer.toString(red, 16) + Integer.toString(green, 16) + Integer.toString(blue, 16); }
%> <html>
<head> <title>Random Color</title> </head> <body bgcolor="white">
Random Color
<table bgcolor="<%= randomColor() %>" > <tr><td width="100" height="100"> </td></tr> </table> </body>
</html></source>
Using Recursion
<source lang="java">
<HTML>
<HEAD> <TITLE>Using Recursion</TITLE> </HEAD> <BODY>
Using Recursion
<%! int factorial(int n) { if (n == 1) { return n; } else { return n * factorial(n - 1); } } %> <% out.println("The factorial of 6 is " + factorial(6)); %> </BODY>
</HTML></source>