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2010-06-01T05:06:40Z

1 версия

в 17:44, 31 мая 2010

2010-05-31T17:44:27Z

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== Getting all annotations for a method ==



<source lang="java">
import java.lang.annotation.Annotation;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.reflect.Method;
// A simple annotation type.
@Retention(RetentionPolicy.RUNTIME)
@interface MyAnnotation {
String stringValue();
int intValue();
}
@Retention(RetentionPolicy.RUNTIME)
@interface What {
String description();
}
@What(description = "An annotation test class")
@MyAnnotation(stringValue = "for class", intValue = 100)
public class MainClass {
// Annotate a method.
@What(description = "An annotation test method")
@MyAnnotation(stringValue = "Annotation Example", intValue = 100)
public static void myMethod() {
}
public static void main(String[] arg) {
try {
MainClass ob = new MainClass();
Method m = ob.getClass( ).getMethod("myMethod");
Annotation[] annos = m.getAnnotations();
System.out.println("All annotations for myMeth:");
for(Annotation a : annos)
System.out.println(a);
} catch (Exception exc) {
}
}
}</source>



<pre class=codeResult>All annotations for myMeth:
@What(description=An annotation test method)
@MyAnnotation(stringValue=Annotation Example, intValue=100)</pre>

== Obtaining All Annotations: getAnnotations( ) ==



<source lang="java">
import java.lang.annotation.Annotation;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
// A simple annotation type.
@Retention(RetentionPolicy.RUNTIME)
@interface MyAnnotation {
String stringValue();
int intValue();
}
@Retention(RetentionPolicy.RUNTIME)
@interface What {
String description();
}
@What(description = "An annotation test class")
@MyAnnotation(stringValue = "for class", intValue = 100)
public class MainClass {
// Annotate a method.
@What(description = "An annotation test method")
@MyAnnotation(stringValue = "Annotation Example", intValue = 100)
public static void myMethod(String str, int i) {
}
public static void main(String[] arg) {
try {
MainClass ob = new MainClass();
Annotation[] annos = ob.getClass().getAnnotations();

System.out.println("All annotations for Meta2:");
for(Annotation a : annos)
System.out.println(a);

} catch (Exception exc) {
}
}
}</source>



<pre class=codeResult>All annotations for Meta2:
@MyAnnotation(stringValue=for class, intValue=100)
@What(description=An annotation test class)</pre>

== Obtaining Annotations at Run Time by Use of Reflection ==



<source lang="java">
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.reflect.Method;
// A simple annotation type.
@Retention(RetentionPolicy.RUNTIME)
@interface MyAnnotation {
String stringValue();
int intValue();
}
public class MainClass {
// Annotate a method.
@MyAnnotation(stringValue = "Annotation Example", intValue = 100)
public static void myMethod() {
}
public static void main(String[] a) {
try {
MainClass ob = new MainClass();
Class c = ob.getClass();
Method m = c.getMethod("myMethod");
MyAnnotation anno = m.getAnnotation(MyAnnotation.class);
System.out.println(anno.stringValue() + " " + anno.intValue());
} catch (NoSuchMethodException exc) {
System.out.println("Method Not Found.");
}
}
}</source>



<pre class=codeResult>Annotation Example 100</pre>

== Reflection: getMethod( ) with parameters ==



<source lang="java">
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.reflect.Method;
// A simple annotation type.
@Retention(RetentionPolicy.RUNTIME)
@interface MyAnnotation {
String stringValue();
int intValue();
}
public class MainClass {
// Annotate a method.
@MyAnnotation(stringValue = "Annotation Example", intValue = 100)
public static void myMethod(String str, int i) {
}
public static void main(String[] a) {
try {
MainClass ob = new MainClass();
Class c = ob.getClass();
Method m = c.getMethod("myMethod", String.class, int.class);
MyAnnotation anno = m.getAnnotation(MyAnnotation.class);
System.out.println(anno.stringValue() + " " + anno.intValue());
} catch (NoSuchMethodException exc) {
System.out.println("Method Not Found.");
}
}
}</source>



<pre class=codeResult>Annotation Example 100</pre>

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Admin: 1 версия

в 17:44, 31 мая 2010