在action中一般的处理方式是:核心servlet或者Filter接收到用户请求后，通常会对用户请求进行简单的预处理，比如解析，封装参数。然后通过反射来创建Action的实例。并调用action指定的方法(struts1中为execute方法，struts2中为任意方法)来处理用户请求，并通过配置文件转发到对应的页面。这样做对一些复杂的处理固然很好，但是像登录这类只返回true或false的字符串二样，就没有必要用这种方式了。可以再action里面调用servlet
api，直接打印输出即可。
下面是一个关于ajax交互action实现简单登录的小例子。该例子中在struts标签<action>中没有配置<result>标签进行跳转，而是在action里面执行打印输出。这样简化了代码的编写。
1.登录界面
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
+ request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'index.jsp' starting page</title>
<script type="text/javascript" src="js/jquery-1.6.4.min.js"></script>
</head>
<script type="text/javascript">
$(function() {
$("#button1").click(function() {
//alert("aaa");
var username = $("#username").val();
var password = $("#password").val();
$.get("test.action", {
"username" : username,
"password":password
}, function(data) {
if(data.indexOf("true") >-1){
window.location.href = "master.jsp";
}
else{
alert("登录失败");
}
},"text");
});
});
</script>
<body>
姓名：
<input type="text" name="username" id="username"> 密码:
<input type="text" name="password" id="password">
<input type="button" id="button1" value="提交">
</body>
</html>
test.action对应的代码
package com.xzy.demo.struts.test;
import java.io.PrintWriter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.apache.struts2.ServletActionContext;
import com.opensymphony.xwork2.ActionSupport;
public class Test extends ActionSupport {
HttpServletRequest request = ServletActionContext.getRequest(); //得到servlet里面的request
HttpServletResponse response = ServletActionContext.getResponse(); //得到servlet里面的response
HttpSession session = request.getSession();
public void login() throws Exception {
String username = request.getParameter("username");
String password = request.getParameter("password");
try {
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
PrintWriter out = response.getWriter();
if(username.equals("xzy") && password.equals("123")){
session.setAttribute("username", username);
out.print("true");//通过out对象直接输出
}else{
out.print("false");
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
登录成功跳转到master.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
response.setCharacterEncoding("utf-8");
request.setCharacterEncoding("utf-8");
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
+ request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'master.jsp' starting page</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
</head>
<body>
<%
try {
if (session.getAttribute("username") != null) {
out.print((String)session.getAttribute("username") + "已经登录");
} else {
out.print("未登录");
}
} catch (Exception e) {
out.print(e.getMessage());
e.printStackTrace();
}
%>
</body>
</html>
此时配置文件不需要配置result标签了。代码如下:
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.1//EN" "http://struts.apache.org/dtds/struts-2.1.dtd">
<struts>
<package name="struts" extends="struts-default">
<action name="test" class="com.xzy.demo.struts.test.Test"
method="login">
</action>
</package>
</struts>
这样不仅简化了代码开发，适用于返回很少量的字符串时使用。