自定义注解

最新推荐文章于 2025-05-19 20:02:25 发布

原创最新推荐文章于 2025-05-19 20:02:25 发布 · 113 阅读

0 ·

CC 4.0 BY-SA版权

java 专栏收录该内容

13 篇文章

订阅专栏

本文介绍了一种使用Java注解来标记水果类属性的方法，通过自定义注解如水果名称、颜色及供应商信息，并利用反射机制获取这些注解的详细信息。

1.`package test;

import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

/**

水果名称注解
*/
@Target(FIELD)
@Retention(RUNTIME)
@Documented
public @interface FruitName {
String value() default “”;
}`

2.package test;

/**

水果颜色注解
/
@Target(FIELD)
@Retention(RUNTIME)
@Documented
public @interface FruitColor {
/*
- 颜色枚举
  */
  public enum Color{ BLUE,RED,GREEN};
/**
- 颜色属性
  */
  Color fruitColor() default Color.GREEN;
  }

3.package test;

/**

水果供应者注解
/
@Target(FIELD)
@Retention(RUNTIME)
@Documented
public @interface FruitProvider {
/*
- 供应商编号
  */
  public int id() default -1;
/**
- 供应商名称
  */
  public String name() default “”;
/**
- 供应商地址
  */
  public String address() default “”;
  }

package test;

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);
    }
 }

}
}

5.package test;

import test.FruitColor.Color;

/**

注解使用
*/
public class Apple {

@FruitName(“Apple”)
private String appleName;

@FruitColor(fruitColor=Color.RED)
private String appleColor;

@FruitProvider(id=1,name=“陕西红富士集团”,address=“陕西省西安市延安路89号红富士大厦”)
private String appleProvider;

public void setAppleColor(String appleColor) {
this.appleColor = appleColor;
}
public String getAppleColor() {
return appleColor;
}

public void setAppleName(String appleName) {
this.appleName = appleName;
}
public String getAppleName() {
return 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”);
}
}