JPA相关--Annotation

1.自定义注解

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

@Target(ElementType.METHOD) //指定可以用在什么地方，默认所有地方
@Retention(RetentionPolicy.RUNTIME ) //指定周期--运行时
public @interface HelloWorld {
    //定义成员
	public String name() default "hello";
}

2.编写解析方法

import java.lang.reflect.Method;

public class AnnotationParser {

	public void parse(Object obj,String methodName){
		Method[]  ms=obj.getClass().getMethods();
		for(Method m:ms){
		 if(m.getName().equals(methodName)){
			if(m.isAnnotationPresent(HelloWorld.class)){
				HelloWorld hWorld=m.getAnnotation(HelloWorld.class);
				//System.out.println(hWorld.name());
				
				try{
					System.out.println("before...");
					m.invoke(obj, null);
					System.out.println("after...");
				}catch (Exception e) {
					e.printStackTrace();
				}
			}
		   }
		}
	}
}

3.Junit测试

被测试的bean：

public class TestBean {

	private String name;

	
	public TestBean(String name) {
		
		this.name = name;
	}

	@HelloWorld(name="change")
	public String getName() {
		System.out.println("getName executed...");
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}
	
	public String toString(){
		return this.name;
	}
	
}

测试方法：

package junit.test;
import org.junit.BeforeClass;
import org.junit.Test;
import com.persia.annotation.AnnotationParser;
import com.persia.annotation.TestBean;

public class AnnotationTest {

	@BeforeClass
	public static void setUpBeforeClass() throws Exception {
	}

	@Test
	public void hello(){
		TestBean tBean=new TestBean("testbean");
		//System.out.println(tBean);
		
		AnnotationParser aParser=new AnnotationParser();
		aParser.parse(tBean, "getName");
	}
}