[java]自定义注解demo

最新推荐文章于 2023-10-20 16:19:30 发布

attwice

最新推荐文章于 2023-10-20 16:19:30 发布

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本文链接：https://blog.youkuaiyun.com/attwice/article/details/17316887

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本文介绍如何通过自定义注解实现属性的注入与获取，并通过实例展示了如何在类中应用该注解，进而实现了属性的动态设置与获取。

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1.自定义注解

package annotation;

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;

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface MyAnnotation {
	String name();

	int age();

	boolean sex();
}

2.使用注解

package annotation;

import java.lang.reflect.Method;

public class Student {
	private String name;
	private int age;
	private boolean sex;

	public void init(String name, int age, boolean sex) {
		this.name = name;
		this.age = age;
		this.sex = sex;
	}

	@MyAnnotation(name = "张三", age = 20, sex = true)
	public void init() {
		try {
			Method method = Student.class.getMethod("init");
			if (method.isAnnotationPresent(MyAnnotation.class)) {
				MyAnnotation anno = method.getAnnotation(MyAnnotation.class);
				this.name = anno.name();
				this.age = anno.age();
				this.sex = anno.sex();
			}
		} catch (SecurityException e) {
			e.printStackTrace();
		} catch (NoSuchMethodException e) {
			e.printStackTrace();
		}
	}

	public void show() {
		System.out.print("{name=" + this.name);
		System.out.print(",age=" + this.age);
		System.out.println(",sex=" + (this.sex ? "男" : "女") + "}");
	}

}

3.测试

package annotation;

public class StudentTest {

	public static void main(String[] args) throws Exception {
		Student stu = new Student();
		stu.init();
		stu.show();
		stu.init("李四", 21, false);
		stu.show();
	}

}

4.打印结果

{name=张三,age=20,sex=男}
{name=李四,age=21,sex=女}