AOP的MethodBeforeAdvice

使用Spring自动生成代理类,spring利用的是动态代理机制
接口

Java代码
public interface UserDao {
void addUser();
void deleteUser();
}
两个实现:

Java代码
public class UserDaoMySqlImpl implements UserDao {  
 
@Override 
public void addUser() {  
  System.out.println("UserDaoMySqlImpl.addUser()");  
}  
 
@Override 
public void deleteUser() {  
  System.out.println("UserDaoMySqlImpl.deleteUser()");  
 
}  
 
}  



public class UserDaoOracleImpl implements UserDao {

@Override
public void addUser() {
  System.out.println("UserDaoOracleImpl.addUser()");
}

@Override
public void deleteUser() {
  System.out.println("UserDaoOracleImpl.deleteUser()");
}

}
Device
import java.lang.reflect.Method;

import org.springframework.aop.MethodBeforeAdvice;

public class UserDaoBeforeAdvice implements MethodBeforeAdvice {

@Override
public void before(Method arg0, Object[] arg1, Object arg2)
   throws Throwable {
  System.out.println("UserDaoBeforeAdvice.before()");
}

}

spring的配置文件

Xml代码
<!-- 配置实现类的bean,可以把所有的实现类都写上 --> 
<bean id="userdao" class="com.dowebber.spring.aop.UserDaoMySqlImpl"></bean> 
<!--配置Advice的bean --> 
<bean id="beforeadvice" class="com.dowebber.spring.aop.UserDaoBeforeAdvice"></bean> 
<!--配置spring自动生成代理对象所需要的一些参数 --> 
<bean id="userdaoproxy" class="org.springframework.aop.framework.ProxyFactoryBean"> 
<property name="proxyInterfaces" value="com.dowebber.spring.aop.UserDao"/> 
<property name="target"> 
  <ref bean="userdao"/> 
</property> 
<property name="interceptorNames"> 
  <list> 
   <value>beforeadvice</value> 
  </list> 
</property> 
</bean> 


测试类:

Java代码
import org.springframework.context.ApplicationContext;  
import org.springframework.context.support.ClassPathXmlApplicationContext;  
 
public class TestUserDaoBeforeDevice {  
 
public static void main(String[] args) {  
    
  ApplicationContext context = new ClassPathXmlApplicationContext("com/dowebber/spring/aop/spring.xml");  
  UserDao dao = (UserDao)context.getBean("userdaoproxy");  
  dao.addUser();  
}  
 
}