By yusijia

Updated:

Contents
  1. 1. 实例1：
    1. 1.1. FruitName.java
    2. 1.2. FruitColor.java
    3. 1.3. Apple.java:
    4. 1.4. FruitInfoUtil.java:
    5. 1.5. Lianxix.java:

实例1：

FruitName.java

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package lianxi;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/***********注解声明***************/

/*
 * 水果名称注解
 * 
 */
@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface FruitName {
	public String value() default "No name";
}

FruitColor.java

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package lianxi;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/***********注解声明***************/

@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface FruitColor {
	 
    /*
     *颜色枚举 
     */
    public enum Color{
    	BULE, RED, GREEN, NOCOLOR;
    }
    
    /*
     *颜色属性 
     */
    public Color fruitColor() default Color.NOCOLOR;
}

FruitProvider.java:

package lianxi;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/***********注解声明***************/

@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface FruitProvider {
	/*
	 * 供应商编号
	 */
	public int id() default -1;
	
	/*
	 * 供应商名称
	 */
	public String name() default "No name";
	
	/*
	 * 供应商地址
	 */
	public String address() default "No address";
	
}

Apple.java:

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package lianxi;

import lianxi.FruitColor.Color;

/***********注解使用实例***************/

public class Apple {
	
	@FruitName(value = "Apple")		//@FruitName("Apple")也行
	private String appleName;
	
	@FruitName(value = "Apple")
	@FruitColor(fruitColor = Color.RED)
	private String appleColor;
	
	@FruitName(value = "Apple")
	@FruitColor(fruitColor = Color.RED)
	@FruitProvider(id = 1, name = "红富士苹果", address = "湖南省")
	private String appleProvider;
	
	public String getAppleColor(){
		return appleColor;
	}
	
	public void setAppleColor(String appleColor){
		this.appleColor = appleColor;
	}
	
	public String getAppleName() {
        return appleName;
    }
	
	public void setAppleName(String appleName) {
        this.appleName = appleName;
    }
    
	public void setAppleProvider(String appleProvider) {
        this.appleProvider = appleProvider;
    }
    public String getAppleProvider() {
        return appleProvider;
    }
    
    public void displayName(){
    	System.out.println("水果的名字是：苹果");
    }
}

FruitInfoUtil.java:

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package lianxi;

import java.lang.reflect.Field;

/***********注解处理器***************/


public class FruitInfoUtil {
	public static void getFruitInfo(Class<?> clazz){
        
        Field[] fields = clazz.getDeclaredFields();
        
        for(Field field : fields)
        {
            Object[] fruits = field.getAnnotations();//获得该元素所有的注解
            for(Object ob : fruits)
            {
            	System.out.println(ob);
            }
            System.out.println("\n");
        }
	}
}

Lianxix.java:

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package lianxi;

import java.util.*;
import java.io.*;
import java.lang.annotation.Documented;
import java.lang.annotation.Retention;


public class lianxix {
    
    public static void main(String[] args){
        FruitInfoUtil.getFruitInfo(Apple.class);
    }
}

输出：
@lianxi.FruitName(value=Apple)


@lianxi.FruitName(value=Apple)
@lianxi.FruitColor(fruitColor=RED)


@lianxi.FruitName(value=Apple)
@lianxi.FruitColor(fruitColor=RED)
@lianxi.FruitProvider(name=红富士苹果, id=1, address=湖南省)
Contents
  1. 1. 实例1：
    1. 1.1. FruitName.java
    2. 1.2. FruitColor.java
    3. 1.3. Apple.java:
    4. 1.4. FruitInfoUtil.java:
    5. 1.5. Lianxix.java: