第一步，导入工程所需jar包

我自己用的是struts-2.5.16-min-lib.zip，解压导入jar。

下载链接：https://pan.baidu.com/s/1f5NGEZfheJu1GvhVC3GYuQ 密码：o9v8

第二步，实现登录功能

package com.bingcao.test;

import com.opensymphony.xwork2.ActionSupport;


public class LoginAction extends ActionSupport {

	private String username;
	private String password;

	public String login() throws Exception {

        if (isInvalid(getUsername())) return INPUT;

        if (isInvalid(getPassword())) return INPUT;

		System.out.println("登录成功");
        return SUCCESS;
    }

    private boolean isInvalid(String value) {
        return (value == null || value.length() == 0);
    }


    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;
    }

}

第三步，配置文件

Struts2配置

这里我用了引用文件的方式，所有有两个xml文件，struts.xml和example.xml。

struts.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
	"-//Apache Software Foundation//DTD Struts Configuration 2.5//EN"
	"http://struts.apache.org/dtds/struts-2.5.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-allowed-methods>regex:.*</global-allowed-methods>
		
		<global-exception-mappings>
			<exception-mapping exception="java.lang.Exception"
				result="error" />
		</global-exception-mappings>
	</package>

	<include file="example.xml" />
	
	<!-- Add packages here -->
</struts>

example.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
	"-//Apache Software Foundation//DTD Struts Configuration 2.5//EN"
	"http://struts.apache.org/dtds/struts-2.5.dtd">

<struts>
	<!-- 限制上传文件的大小，第一种方式：通过修改Struts2的常量。 在default.properties中配的Struts.multipart.maxSize=2097152 -->
	<constant name="struts.multipart.maxSize" value="5242880"></constant>
	<constant name="struts.ognl.allowStaticMethodAccess" value="true"></constant>
	
		
	<package name="topic" extends="default">
		
		<action name="Topic_*" class="com.bingcao.test.TopicAction" method="{1}">
			<result name="list">/index.jsp</result>
		</action>
		
	</package>
	
	<package name="user" extends="default">
		        
        <action name="Login_*" method="{1}" class="com.bingcao.test.LoginAction">
            <result>/test/Welcome.jsp</result>
            <result name="input">/test/Login.jsp</result>
        </action>
        
	</package>
		
</struts>

web.xml配置

从官方demo中看到，struts2.5有两个***，struts-prepare和struts-execute，目前自己分不清，都用上了。

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>sh_tieba</display-name>
  
  <filter>
    <filter-name>struts-prepare</filter-name>
    <filter-class>org.apache.struts2.dispatcher.filter.StrutsPrepareFilter</filter-class>
  </filter>
  <filter>
    <filter-name>struts-execute</filter-name>
    <filter-class>org.apache.struts2.dispatcher.filter.StrutsExecuteFilter</filter-class>
  </filter>
  
  <filter-mapping>
    <filter-name>struts-prepare</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>
  <filter-mapping>
    <filter-name>struts-execute</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>
  
  
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
</web-app>

第四步，jsp的登录页面

Login.jsp

<%@ page contentType="text/html; charset=UTF-8" %>
<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
    <title>Sign On</title>
</head>

<body>
<s:form action="Login_login">
    <s:textfield key="username"/>
    <s:password key="password" />
    <s:submit/>
</s:form>
</body>
</html>

Welcome.jsp

<%@ page contentType="text/html; charset=UTF-8" %>
<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
    <title>Welcome</title>
</head>

<body>
	<h3>登录成功</h3>
</body>
</html>

我的文件部署：

其中遇到的问题

原来是因为struts2.5为了提升安全性，添加了一个allowed-methods属性，此属性指定可被调用的方法。

allowed-methods属性还可以使用正则表达式配置：

<global-allowed-methods>regex:.*</global-allowed-methods>

struts2.5的小例子