java 注解示例（使用注解为对象赋值）

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java 注解示例

 

使用注解结合反射可以为实例对象赋值

 

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示例

 

@Retention(RetentionPolicy.RUNTIME)
@interface D{
    String value() default "";
}

class Person{

    private String name;
    private Integer age;

    public String getName() {
        return name;
    }

    @D("瓜田李下")
    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    @D("24")
    public void setAge(Integer age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return this.name+"  "+this.age;
    }
}

public class MyTest4 {

    public static void main(String[] args) throws Exception {
        Class c=Class.forName("hello3.Person");
        Person person=(Person)c.getDeclaredConstructor().newInstance();

        Method nameMethod=c.getDeclaredMethod("setName", String.class);
        if (nameMethod.isAnnotationPresent(D.class)){
            D d=nameMethod.getAnnotation(D.class);
            nameMethod.invoke(person,d.value());
        }

        Method ageMethod=c.getDeclaredMethod("setAge", Integer.class);
        if (ageMethod.isAnnotationPresent(D.class)){
            D d=ageMethod.getAnnotation(D.class);
            ageMethod.invoke(person,Integer.valueOf(d.value().toString()));
        }

        System.out.println(person);
    }
}

 

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控制台输出

 

瓜田李下  24