[java]自定义注解demo

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}