自定义Annotation

拼搏现实的明天。 2022-08-26 01:21 139阅读 0赞

package com.test.javaSe01;
    
    import java.lang.annotation.Retention;
    import java.lang.annotation.RetentionPolicy;
    import java.lang.reflect.Method;
    
    @Retention(value = RetentionPolicy.RUNTIME)
    // 此句必须有//\u6B64\u53E5\u5FC5\u987B\u6709
    @interface MySelfAnnotation {
    	public int age() default 23;
    
    	public String name() default "ctl";
    }
    
    @MySelfAnnotation(age = 100, name = "蔡腾林")
    class Person {
    	int age;
    	String name;
    
    	public int getAge() {
    		return age;
    	}
    
    	public void setAge(int age) {
    		this.age = age;
    	}
    
    	public String getName() {
    		return name;
    	}
    
    	public void setName(String name) {
    		this.name = name;
    	}
    
    	public int hashCode() {
    		return super.hashCode();
    	}
    
    	@MySelfAnnotation(age = 230, name = "ctllin")
    	public String toString() {
    		return this.name + " " + this.age;
    	}
    
    	@MySelfAnnotation
    	public void print() {
    
    	}
    }
    
    /**
     * 
     * @author Administrator
     * @deprecated 获取自定义Annotation中的值 自定义的Annotation分别定义到类和方法上
     */
    public class SelfAnnotationTestDemo {
    	public static void main(String[] args) {
    		SelfAnnotationTestDemo sa = new SelfAnnotationTestDemo();
    		Class<?> c = null;
    		try {
    			c = Class.forName("com.test.javaSe01.Person");
    			if (c.isAnnotationPresent(MySelfAnnotation.class)) {
    				MySelfAnnotation ma = c.getAnnotation(MySelfAnnotation.class);
    				System.out.println(ma.name() + " " + ma.age());
    			}
    		} catch (ClassNotFoundException e) {
    			System.err.println("com.test.javaSe01.Person没有找到");
    			e.printStackTrace();
    		}
    		Method method = null, method1 = null;
    		try {
    			method = c.getMethod("toString");
    			System.out.println(method);
    			method1 = c.getMethod("print");
    			System.out.println(method1);
    		} catch (SecurityException e) {
    			e.printStackTrace();
    		} catch (NoSuchMethodException e) {
    			e.printStackTrace();
    		}
    		if (method.isAnnotationPresent(MySelfAnnotation.class)) {
    			MySelfAnnotation myAnnotation = method
    					.getAnnotation(MySelfAnnotation.class);
    			int age = myAnnotation.age();
    			String name = myAnnotation.name();
    			System.out.println(name + " " + age);
    		}
    		if (method1.isAnnotationPresent(MySelfAnnotation.class)) {
    			MySelfAnnotation myAnnotation = method1
    					.getAnnotation(MySelfAnnotation.class);
    			int age = myAnnotation.age();
    			String name = myAnnotation.name();
    			System.out.println(name + " " + age);
    		}
    	}
    }