注解

1.元注解

• @Target 说明修饰对象范围
• @Retention : 定义该注解被保留的时间长短，SOURCE 源文件保留,CLASS class文件保留,RUNTIME 运行时保留
• @Documented ：描述javadoc
• @Inherited : 阐述了某个被标注的类型是被继承的

2.注解处理

• TestProvider注解

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

    public int id() default -1;
    public String name() default "";
    public String address() default "";
}

• Apple

public class Apple {
    @TestProvider(id = 1,name = "lwx",address = "aaa")
    private String testProvider;

    public String getTestProvider() {
        return testProvider;
    }

    public void setTestProvider(String testProvider) {
        this.testProvider = testProvider;
    }
}

• Util

public class Util {
    public static void getTest(Class<?> clazz){
        String str = "lwx";
        Field[] fields = clazz.getDeclaredFields();
        for (Field field : fields){
            if (field.isAnnotationPresent(TestProvider.class)){
                TestProvider testProvider = (TestProvider) field.getAnnotation(TestProvider.class);
                str = testProvider.id() + testProvider.name();
                System.out.println(str);
            }
        }
    }

    public static void main(String[] args) {
        Util.getTest(Apple.class);
    }
}