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    3. java反射8（注解）

    java反射8（注解）

    xiaoxiao2021-03-25  109
    package com.betasoft; import java.lang.annotation.ElementType; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.annotation.Target; @Target({ElementType.TYPE,ElementType.FIELD,ElementType.METHOD,ElementType.LOCAL_VARIABLE}) @Retention(RetentionPolicy.RUNTIME) public @interface AnnotationTest { //定义两个成员变量 String name() default "JACK"; int age() default 20;

    }

    package com.betasoft; import java.lang.annotation.Annotation; public class TestAnnotation { public static void main(String[] args) { try { TestAnnotation t = new TestAnnotation(); t.getInfo(); } catch (NoSuchMethodException e) { e.printStackTrace(); } catch (SecurityException e) { e.printStackTrace(); } } @AnnotationTest(name="张三",age=26) public void getInfo() throws NoSuchMethodException, SecurityException{ //获取TestAnnotation对象getinfo方法里的所有注解 Annotation[] annos = TestAnnotation.class.getMethod("getInfo").getAnnotations(); //遍历annos数组 for(Annotation ann: annos){ //ann就是一个Annotation对象 //判断当前ann是否是AnnotationTest类型 if(ann instanceof AnnotationTest){ System.out.println("ann是"+ann); //需要将ann强制转成AnnotationTest System.out.println("ann的name是"+((AnnotationTest)ann).name()); System.out.println("ann的age是"+((AnnotationTest)ann).age()); } } } }

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