Java基本注解以及了解自定义注解

import java.util.ArrayList;
import java.util.List;

/*
* 注解
* 1.JDK提供的常用的注解
*  @Override: 限定重写父类方法, 该注释只能用于方法
@Deprecated: 用于表示某个程序元素(类, 方法等)已过时
@SuppressWarnings: 抑制编译器警告
2.如何自定义一个注解
3.元注解

*/
public class TestAnnotation {
public static void main(String[] args) {
Person p = new Student();
p.walk();
p.eat();

@SuppressWarnings({ "rawtypes", "unused" })
List list = new ArrayList();

@SuppressWarnings("unused")
int i = 10;
//		System.out.println(i);
}
}
@MyAnnotation(value = "heheda")
class Student extends Person{
@Override
public void walk(){
System.out.println("学生走路");
}
@Override
public void eat(){
System.out.println("学生吃饭");
}
}
@Deprecated
class Person{
String name;
int age;

public Person() {
super();
}
@MyAnnotation(value = "heheda")
public Person(String name, int age) {
super();
this.name = name;
this.age = age;
}
@MyAnnotation(value = "heheda")
public void walk(){
System.out.println("走路");
}
@Deprecated
public void eat(){
System.out.println("吃饭");
}
@Override
public String toString() {
return "Person [name=" + name + ", age=" + age + "]";
}
}

import static java.lang.annotation.ElementType.CONSTRUCTOR;
import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.ElementType.LOCAL_VARIABLE;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.ElementType.PARAMETER;
import static java.lang.annotation.ElementType.TYPE;

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

//自定义的注解
@Target({TYPE,FIELD, METHOD, PARAMETER, CONSTRUCTOR, LOCAL_VARIABLE})
@Retention(RetentionPolicy.RUNTIME)
public @interface MyAnnotation {
String value() default "hello";
}