最近我需要在不改变原有的代码的前提下，记录到达struts action的HttpServletRequest和HttpServletResponse，我的第一想法就是用spring aop来做拦截。但是，这样做使得原来struts action无法获得struts上下文的内容信息，为了说明问题，我写了一个小原型，代码如下：
[color=red]类SimpleAction，这个类是用来封装获得HttpServletRequest和HttpServletResponse的方法的，跟本主题关系不大，可以跳过。[/color]
package action;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts2.interceptor.ServletRequestAware;
import org.apache.struts2.interceptor.ServletResponseAware;
import org.apache.struts2.interceptor.SessionAware;
import com.opensymphony.xwork2.ActionSupport;
public class SimpleAction extends ActionSupport implements ServletRequestAware, ServletResponseAware ,SessionAware{
protected HttpServletRequest servletRequest;
protected HttpServletResponse servletResponse;
protected Map session;
public Map getSession() {
return session;
}
public void setSession(Map session) {
this.session = session;
}
public void setServletRequest(HttpServletRequest request)
{
this.servletRequest = request;
}
public HttpServletRequest getServletRequest()
{
return this.servletRequest;
}
public void setServletResponse(HttpServletResponse response)
{
this.servletResponse = response;
}
public HttpServletResponse getServletResponse()
{
return this.servletResponse;
}
}
类LoginAction，这个类的execute就是struts处理action调用的方法，但是奇怪的是，在这个方法中，本应得到jsp传来的值得username和password为空（把spring aop相关配置注释掉之后，username和password能正常传值）。loginService.validate（）用作判断username和password是否符合，不符合以抛出异常的方式来告知调用者。在加上spring aop后，由于[color=red]username和password为空[/color]，所以就一直返回结果"usernameInvalid"。
package action;
import org.apache.struts2.interceptor.ServletRequestAware;
import org.apache.struts2.interceptor.ServletResponseAware;
import org.apache.struts2.interceptor.SessionAware;
import service.LoginService;
import exception.*;
public class LoginAction extends SimpleAction {
private String username;
private String password;
private LoginService loginService;
public LoginService getLoginService()
{
return loginService;
}
public void setLoginService(LoginService loginService)
{
this.loginService = loginService;
}
public String getUsername()
{
return username;
}
public void setUsername(String username)
{
this.username = username;
}
public String getPassword()
{
return password;
}
public void setPassword(String password)
{
this.password = password;
}
@Override
public void validate()
{
}
@Override
public String execute()
{
try{
this.getServletRequest().setAttribute("username", username);
this.getServletRequest().setAttribute("password", password);
System.out.println("username"+username);
System.out.println("username"+getUsername());
boolean result = loginService.validate(username, password);
}catch(UsernameException ue)
{
return "usernameInvalid";
}catch(PasswordException pe)
{
return "passwordInvalid";
}catch(Exception e)
{
e.printStackTrace();
return INPUT;
}
return SUCCESS;
}
}
下面是advice类，用来处理调用方法后的日志记录工作
package advice;
import java.io.*;
import java.lang.reflect.Method;
import org.apache.log4j.Logger;
import org.apache.log4j.PropertyConfigurator;
import org.springframework.aop.AfterReturningAdvice;
import org.springframework.aop.MethodBeforeAdvice;
import org.springframework.aop.ThrowsAdvice;
public class LogActionAdvice implements
AfterReturningAdvice
{
public void afterReturning(Object arg0, Method arg1, Object[] arg2,
Object target) {
// TODO Auto-generated method stub
try
{
PropertyConfigurator.configure("after.properties");
Logger logger = Logger.getLogger(target.getClass());
logger.debug("...");
}catch(Exception e)
{
e.printStackTrace();
}
}
}
下面是login页面，这个页面的username空间对应action的username属性，所以应该不是struts没有配alias的问题，这里是login.jsp代码
<%@ page language="java" pageEncoding="GB2312"%>
<%@ taglib prefix="s" uri="/struts-tags"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//CN">
login2
/s:textfield
/s:password
/s:submit
/s:form
下面是配置文件，首先是struts的配置文件struts.xml：
<?xml version="1.0" encoding="GB2312" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd">
/index.jsp
/login.jsp
/usernameInvalid.jsp
/passwordInvalid.jsp
再来是spring的配置文件applicationContext.xml，红色部分是advice的配置，具体是匹配所有*Action的execute方法。
<?xml version="1.0" encoding="UTF-8"?>
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:jee="http://www.springframework.org/schema/jee"
xmlns:tx="http://www.springframework.org/schema/tx" xmlns:ehcache="http://www.springmodules.org/schema/ehcache"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-2.5.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd http://www.springmodules.org/schema/ehcache http://www.springmodules.org/schema/cache/springmodules-ehcache.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd"
default-lazy-init="true" default-autowire="byName">
[color=red] aop:config
/aop:config
[/color]
<bean name="loginService" class="service.LoginService" />
<bean name="LoginAction" class="action.LoginAction">
<property name="loginService">
<ref bean="loginService"/>
</property>
</bean>
最后是web.xml的源码：
<?xml version="1.0" encoding="UTF-8"?>
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<!-- 加载struts2核心 -->
struts2
org.apache.struts2.dispatcher.FilterDispatcher
struts2
/*
<!-- 指明spring配置文件在何处 -->
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:applicationContext.xml</param-value>
</context-param>
<!-- 加载spring配置文件applicationContext.xml -->
<listener>
<listener-class>
org.springframework.web.context.ContextLoaderListener
</listener-class>
</listener>
在这个原型中出现的问题是，在LoginAction中，username和password为空，但是，[color=red]如果把它们set到 HttpServletRequest中，在页面usernameInvalid.jsp中却能够得到username和password的值。[/color]事先我查过一些资料，说用spring aop自动生成的代理无法获得struts上下文传递的变量值，但是我想不通为何把它们set到HttpServletRequest后却能够在前端页面显示出正确的值。
谢谢您的阅读和帮助！
