java注解反射简单实例

packagecom.anno;

importjava.lang.annotation.ElementType;
importjava.lang.annotation.Retention;
importjava.lang.annotation.RetentionPolicy;
importjava.lang.annotation.Target;

@Retention(RetentionPolicy.RUNTIME) //表示注解在运行时依然存在
@Target(ElementType.METHOD) //表示注解可以使用在方法上
public @interfaceCallAnnotation {

    String phone() default "某某";; //表示注解须要一个参数，默认值为"某某"
}

packagecom.anno;


public classPerson {

    public voidcall( String phone) {
        System.out.println("call=>"+phone);
    }
    
    
    @CallAnnotation
    public voidcallByAnnotationDefault(String phone){
        System.out.println("callByAnnotationDefault=>"+phone);
    }
    
    
    @CallAnnotation(phone = "张三")
    public voidcallByUserAnnotation(String phone){
        System.out.println("callUserAnnotation=>"+phone);
    }


}

packagecom.anno;

importjava.lang.reflect.InvocationTargetException;
importjava.lang.reflect.Method;

public classTestAnno {

    public static voidmain(String[] args)
            throwsIllegalAccessException, IllegalArgumentException, InvocationTargetException {
        
        Person person = new Person(); //创建person对象
        Method[] methods = Person.class.getDeclaredMethods(); //得到所有方法
        for(Method meth : methods) {
            CallAnnotation annoTemp = null;

            annoTemp = meth.getAnnotation(CallAnnotation.class); //得到注解对象
            System.out.println("调用方法名称:" +meth.getName());
            System.out.println("注释的对象信息:" +annoTemp);
            if (annoTemp != null) { //如果注解对象不为空，将参数值设为注解的值
meth.invoke(person, annoTemp.phone());
            } else{
                meth.invoke(person, "李四"); //如果注解对象为空，单独设置参数值
}

            System.out.println();
        }
    }

}