@interface使用

1.类级别
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.TYPE)
public @interface Element {

int id();String type();

}
2.参数字段

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.FIELD)
public @interface MyParam {

String paramName();

}
3.class
@Element(id = 1, type = “boy”)
public class Boy {

@MyParam(paramName = "name")private String name;public String getName() {    return name;}public void setName(String name) {    this.name = name;}

}
4.测试类
public class Test {

public static void main(String[] args) {    Element loveElement = Boy.class.getAnnotation(Element.class);    System.out.println(loveElement.id());    System.out.println(loveElement.type());    Field[] fields = Boy.class.getDeclaredFields();    for (Field field : fields) {        MyParam myParam = field.getAnnotation(MyParam.class);        System.out.println(field.getName());        System.out.println(myParam.paramName());    }}

}