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");
}
}