利用反射获取类或者方法或者字段上的注解的值

import java.lang.reflect.Field;  
import java.lang.reflect.InvocationTargetException;  
import java.lang.reflect.Method;  
  
/** 
 * 测试Annotation 
 * @author zkn 
 * 
 */  
@AnnotationTest02(getUserName="zhangsan")  
public class AnnotationTest03 {  
  
    @AnnotationTest01(color="red")  
    public static String testColor(String color){  
        System.out.println(color);  
        return color;  
    }  
      
    @AnnotationTest04(getAddress="北京市海淀区")  
    String address;  
      
    public static void main(String[] args) {  
        //获取方法上的注解值  
        Method[] methods = AnnotationTest03.class.getDeclaredMethods();  
        if(methods != null){  
            for(Method method : methods){  
                AnnotationTest01 annotation = method.getAnnotation(AnnotationTest01.class);  
                if(annotation == null)  
                    continue;  
                Method[] me = annotation.annotationType().getDeclaredMethods();  
                for(Method meth : me){  
                    try {  
                        String color = (String) meth.invoke(annotation,null);  
                        System.out.println(color);  
                    } catch (IllegalAccessException e) {  
                        e.printStackTrace();  
                    } catch (IllegalArgumentException e) {  
                        e.printStackTrace();  
                    } catch (InvocationTargetException e) {  
                        e.printStackTrace();  
                    }  
                }  
            }  
        }  
  
        //获取类上的注解值  
        AnnotationTest02 anno = AnnotationTest03.class.getAnnotation(AnnotationTest02.class);  
        if(anno != null){  
            Method[] met = anno.annotationType().getDeclaredMethods();  
            for(Method me : met ){  
                if(!me.isAccessible()){  
                    me.setAccessible(true);  
                }  
                try {  
                    System.out.println(me.invoke(anno, null));  
                } catch (IllegalAccessException e) {  
                    e.printStackTrace();  
                } catch (IllegalArgumentException e) {  
                    e.printStackTrace();  
                } catch (InvocationTargetException e) {  
                    e.printStackTrace();  
                }  
            }  
        }  
          
        //获取字段上的注解值  
        AnnotationTest03 noon = new AnnotationTest03();  
        Field[] field = AnnotationTest03.class.getDeclaredFields();  
        if(field != null){  
            for(Field fie : field){  
                if(!fie.isAccessible()){  
                    fie.setAccessible(true);  
                }  
                AnnotationTest04 annon = fie.getAnnotation(AnnotationTest04.class);  
                Method[] meth = annon.annotationType().getDeclaredMethods();  
                for(Method me : meth){  
                    if(!me.isAccessible()){  
                        me.setAccessible(true);  
                    }  
                    try {  
                        //给字段重新赋值  
                        fie.set(noon, me.invoke(annon, null));  
                        System.out.println(fie.get(noon));  
                    } catch (IllegalAccessException e) {  
                        e.printStackTrace();  
                    } catch (IllegalArgumentException e) {  
                        e.printStackTrace();  
                    } catch (InvocationTargetException e) {  
                        e.printStackTrace();  
                    }  
                }  
                  
            }  
        }  
    }  
}  

 

import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

/**
 * 测试Annotation
 * @author zkn
 *
 */
@AnnotationTest02(getUserName="zhangsan")
public class AnnotationTest03 {

    @AnnotationTest01(color="red")
    public static String testColor(String color){
        System.out.println(color);
        return color;
    }

    @AnnotationTest04(getAddress="北京市海淀区")
    String address;

    public static void main(String[] args) {
        //获取方法上的注解值
        Method[] methods = AnnotationTest03.class.getDeclaredMethods();
        if(methods != null){
            for(Method method : methods){
                AnnotationTest01 annotation = method.getAnnotation(AnnotationTest01.class);
                if(annotation == null)
                    continue;
                Method[] me = annotation.annotationType().getDeclaredMethods();
                for(Method meth : me){
                    try {
                        String color = (String) meth.invoke(annotation,null);
                        System.out.println(color);
                    } catch (IllegalAccessException e) {
                        e.printStackTrace();
                    } catch (IllegalArgumentException e) {
                        e.printStackTrace();
                    } catch (InvocationTargetException e) {
                        e.printStackTrace();
                    }
                }
            }
        }

        //获取类上的注解值
        AnnotationTest02 anno = AnnotationTest03.class.getAnnotation(AnnotationTest02.class);
        if(anno != null){
            Method[] met = anno.annotationType().getDeclaredMethods();
            for(Method me : met ){
                if(!me.isAccessible()){
                    me.setAccessible(true);
                }
                try {
                    System.out.println(me.invoke(anno, null));
                } catch (IllegalAccessException e) {
                    e.printStackTrace();
                } catch (IllegalArgumentException e) {
                    e.printStackTrace();
                } catch (InvocationTargetException e) {
                    e.printStackTrace();
                }
            }
        }

        //获取字段上的注解值
        AnnotationTest03 noon = new AnnotationTest03();
        Field[] field = AnnotationTest03.class.getDeclaredFields();
        if(field != null){
            for(Field fie : field){
                if(!fie.isAccessible()){
                    fie.setAccessible(true);
                }
                AnnotationTest04 annon = fie.getAnnotation(AnnotationTest04.class);
                Method[] meth = annon.annotationType().getDeclaredMethods();
                for(Method me : meth){
                    if(!me.isAccessible()){
                        me.setAccessible(true);
                    }
                    try {
                        //给字段重新赋值
                        fie.set(noon, me.invoke(annon, null));
                        System.out.println(fie.get(noon));
                    } catch (IllegalAccessException e) {
                        e.printStackTrace();
                    } catch (IllegalArgumentException e) {
                        e.printStackTrace();
                    } catch (InvocationTargetException e) {
                        e.printStackTrace();
                    }
                }

            }
        }
    }
}