Entity 类注解 Field参数注解

3、使用自定义的注解类，给Person类以及name、age使用，并给注解类中value赋值

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

/**
 * Created by   on 2018/5/10.
 */
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.TYPE)  //类
public @interface Entity {
    //默认值
    String value() default "I  LOVE  U";
}

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

/**
 * Created by   on 2018/5/10.
 */


@Retention(RetentionPolicy.RUNTIME)
@Target( ElementType.FIELD)  //参数
public @interface Field {

    String value() default  "";
}

/**
 * Created by   on 2018/5/10.
 */
@Entity(value = "This is my frist modle")  //类 注解
public class Person  {
    @Field(value = "小名")   //属性注解
   private String name;
    @Field(value = "18")   //属性注解
    String age;
}

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import java.lang.reflect.Field;


public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Class<Person> personClass = Person.class;
        Entity annotation = personClass.getAnnotation(Entity.class);
        Log.d("Test--------------",annotation.value());
        try {
            Class<Person> personClass1 = Person.class;
            Field name = personClass1.getDeclaredField("name");
            com.bawei.xiongda.Field annotation1 = name.getAnnotation(com.bawei.xiongda.Field.class);
            String value = annotation1.value();
            
            String age = personClass1.getDeclaredField("age").getAnnotation(com.bawei.xiongda.Field.class).value();
            Log.d("Test--+++++------------","name:"+value+"age:"+age );
        } catch (NoSuchFieldException e) {
            e.printStackTrace();
        }
    }
}