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struts.xml:
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
"http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
<!--
<constant name="struts.enable.DynamicMethodInvocation" value="false" />
<constant name="struts.devMode" value="true" />
<package name="default" namespace="/" extends="struts-default">
<default-action-ref name="index" />
<global-results>
<result name="error">/error.jsp</result>
</global-results>
<global-exception-mappings>
<exception-mapping exception="java.lang.Exception" result="error"/>
</global-exception-mappings>
<action name="index">
<result type="redirectAction">
<param name="actionName">HelloWorld</param>
<param name="namespace">/example</param>
</result>
</action>
</package>
<include file="example.xml"/>
-->
<!-- Add packages here -->
<package name="default" namespace="/hello/xxx" extends="struts-default">
<result-types>
<result-type name="captcha" class="com.itheima.results.CaptchaResult"/>
</result-types>
<!--<action name="sayHello" class="com.itheima.actions.HelloAction" method="sayHello">
<result name="success" type="dispatcher">/1.jsp</result>
</action> -->
<action name="captcha">
<result name="success" type="captcha"></result>
</action>
</package>
</struts>
type="captcha" 对应的是上面声明过的 result-type name="captcha"
CaptchaResult:
package com.itheima.results;
import java.awt.image.BufferedImage;
import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts2.ServletActionContext;
import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.Result;
//自定义结果类型
public class CaptchaResult implements Result {
//输出captcha图像
public void execute(ActionInvocation invocation) throws Exception {
HttpServletResponse response = ServletActionContext.getResponse();
//图片不要缓存
response.setHeader("Expires", "-1");
response.setHeader("Cache-Control", "no-cache");
response.setHeader("Pragma", "no-cache");
BufferedImage image = CaptchaUtil.genImage();//得到图片
ImageIO.write(image, "jpeg", response.getOutputStream());
//让程序继续往下走
invocation.invoke();
}
}
Login.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>用户登陆</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
</head>
<body>
<form action="">
用户名:<input type="text" name="username"/><br/>
验证码:<img src="${pageContext.request.contextPath}/hello/xxx/captcha.action"/><br/>
<input type="submit" value="登陆"/>
</form>
</body>
</html>
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原文地址：http://www.cnblogs.com/vaer/p/4691293.html
