By yusijia

Updated:

Contents
  1. 1. 实例1：
    1. 1.1. FruitName.java
    2. 1.2. FruitProvider.java:
    3. 1.3. FruitInfoUtil.java:
    4. 1.4. 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

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:

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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 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:

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;
	
	@FruitColor(fruitColor = Color.RED)
	private String appleColor;
	
	@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){
		
		String strFruitName=" 水果名称：";
        String strFruitColor=" 水果颜色：";
        String strFruitProvicer="供应商信息：";
        
        Field[] fields = clazz.getDeclaredFields();
        
        for(Field field : fields){
        	if(field.isAnnotationPresent(FruitName.class)){
                FruitName fruitName = (FruitName) field.getAnnotation(FruitName.class);
                strFruitName = strFruitName + fruitName.value();
                System.out.println(strFruitName);
            }
        	 else if(field.isAnnotationPresent(FruitColor.class)){
                 FruitColor fruitColor = (FruitColor) field.getAnnotation(FruitColor.class);
                 strFruitColor = strFruitColor + fruitColor.fruitColor().toString();
                 System.out.println(strFruitColor);
             }
             else if(field.isAnnotationPresent(FruitProvider.class)){
                 FruitProvider fruitProvider =  (FruitProvider) field.getAnnotation(FruitProvider.class);
                 strFruitProvicer = " 供应商编号：" + fruitProvider.id() + " 供应商名称：" + fruitProvider.name()+" 供应商地址："+fruitProvider.address();
                 System.out.println(strFruitProvicer);
             }
        }
	}
}

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：
水果名称：Apple
 水果颜色：RED
 供应商编号：1 供应商名称：陕西红富士集团 供应商地址：陕西省西安市延安路89号红富士大厦
Contents
  1. 1. 实例1：
    1. 1.1. FruitName.java
    2. 1.2. FruitProvider.java:
    3. 1.3. FruitInfoUtil.java:
    4. 1.4. Lianxix.java: