第二章 一个简单的Login 应用程序

第一节 需求定义

简单的需求如下图

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mso-ascii-font-family: Garamond; mso-hansi-font-family: Garamond">用户处在</span><span lang="EN-US" style="mso-fareast-font-family: 宋体"><font face="Garamond">Welcome.jsp </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Garamond; mso-hansi-font-family: Garamond">页面，点击登录连接到达</span><span lang="EN-US" style="mso-fareast-font-family: 宋体"><font face="Garamond">Login.jsp</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Garamond; mso-hansi-font-family: Garamond">页面</span><span lang="EN-US" style="mso-fareast-font-family: 宋体"><p></p></span></font></p> <p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt"><font size="3"><span lang="EN-US" style="mso-fareast-font-family: 宋体"><font face="Garamond">2 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Garamond; mso-hansi-font-family: Garamond">在</span><span lang="EN-US" style="mso-fareast-font-family: 宋体"><font face="Garamond">Login.jsp</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Garamond; mso-hansi-font-family: Garamond">输入用户名密码，点击登陆按钮，转到</span><span lang="EN-US" style="mso-fareast-font-family: 宋体"><font face="Garamond">LoginAction</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Garamond; mso-hansi-font-family: Garamond">处理</span><span lang="EN-US" style="mso-fareast-font-family: 宋体"><p></p></span></font></p> <p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt"><font size="3"><span lang="EN-US" style="mso-fareast-font-family: 宋体"><font face="Garamond">3.1 </font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Garamond; mso-hansi-font-family: Garamond">在登陆成功的情况下，再回到</span><span lang="EN-US" style="mso-fareast-font-family: 宋体"><font face="Garamond">Welcome.jsp</font></span><span style="FONT-FAMILY: 宋体; mso-ascii-font-family: Garamond; mso-hansi-font-family: Garamond">页面，在页面上显示登录信息</span><span lang="EN-US" style="mso-fareast-font-family: 宋体"><p></p></span></font></p> <p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt"><font size="3"><span lang="EN-US" style="mso-fareast-font-family: 宋体"><font face="Garamond">3.2 </font></span><span style="FONT-FAMILY: 宋体; 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POSITION: absolute; TOP: 8415px; HEIGHT: 308px" stroked="f" type="#_x0000_t202"><textbox style="mso-next-textbox: #_x0000_s1036" inset="5.85pt,.7pt,5.85pt,.7pt"><table cellspacing="0" cellpadding="0" width="100%"><tbody><tr> <td style="BORDER-LEFT-COLOR: #d4d0c8; BORDER-BOTTOM-COLOR: #d4d0c8; BORDER-TOP-COLOR: #d4d0c8; BACKGROUND-COLOR: transparent; BORDER-RIGHT-COLOR: #d4d0c8"> <div> <p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt"><span lang="EN-US" style="FONT-FAMILY: 宋体"><font size="3">Login.jsp</font></span></p> </div> </td> </tr></tbody></table></textbox></shape></group><group id="_x0000_s1037" style="LEFT: 3862px; WIDTH: 4320px; POSITION: absolute; TOP: 1985px; HEIGHT: 900px" coordsize="3217,771" coordorigin="4119,7952"><line id="_x0000_s1038" style="POSITION: absolute; flip: y" from="4119,8261" to="4119,8723"><font size="3"></font></line><line id="_x0000_s1039" style="POSITION: absolute" from="4119,8261" to="7336,8261"><font size="3"></font></line><line id="_x0000_s1040" style="POSITION: absolute" from="7336,8261" to="7336,8723"><stroke endarrow="block"><font size="3"></font></stroke></line><shape id="_x0000_s1041" style="LEFT: 5038px; WIDTH: 1074px; POSITION: absolute; TOP: 7952px; HEIGHT: 309px" stroked="f" type="#_x0000_t202"><textbox style="mso-next-textbox: #_x0000_s1041" inset="5.85pt,.7pt,5.85pt,.7pt"><table cellspacing="0" cellpadding="0" width="100%"><tbody><tr> <td style="BORDER-LEFT-COLOR: #d4d0c8; BORDER-BOTTOM-COLOR: #d4d0c8; BORDER-TOP-COLOR: #d4d0c8; BACKGROUND-COLOR: transparent; BORDER-RIGHT-COLOR: #d4d0c8"> <div> <p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt"><font size="3"><span lang="EN-US" style="FONT-FAMILY: 宋体">1 </span><span style="FONT-FAMILY: 宋体">开始登陆</span><span lang="EN-US" style="mso-fareast-font-family: 宋体"><p></p></span></font></p> </div> </td> </tr></tbody></table></textbox></shape></group><rect id="_x0000_s1042" style="LEFT: 4942px; WIDTH: 1980px; POSITION: absolute; TOP: 5585px; HEIGHT: 1981px"><textbox inset="5.85pt,.7pt,5.85pt,.7pt"><font size="3"></font></textbox></rect><group id="_x0000_s1043" style="LEFT: 6922px; WIDTH: 1260px; POSITION: absolute; TOP: 4863px; HEIGHT: 1442px" coordsize="1260,1442" coordorigin="6922,4863"><line id="_x0000_s1044" style="POSITION: absolute" from="8180,4863" to="8180,6303"><font size="3"></font></line><line id="_x0000_s1045" style="POSITION: absolute; flip: x" from="6922,6305" to="8182,6305"><stroke endarrow="block"><font size="3"></font></stroke></line></group><group id="_x0000_s1046" style="LEFT: 3862px; WIDTH: 1080px; POSITION: absolute; TOP: 4865px; HEIGHT: 1440px" coordsize="1080,1440" coordorigin="3862,4865"><line id="_x0000_s1047" style="POSITION: absolute; flip: x" from="3862,6305" to="4942,6305"><font size="3"></font></line><line id="_x0000_s1048" style="POSITION: absolute; flip: y" from="3862,4865" to="3862,6305"><stroke endarrow="block"><font size="3"></font></stroke></line></group><shape id="_x0000_s1049" style="LEFT: 7460px; WIDTH: 1260px; POSITION: absolute; TOP: 6483px; HEIGHT: 360px" stroked="f" type="#_x0000_t202"><textbox inset="5.85pt,.7pt,5.85pt,.7pt"><table cellspacing="0" cellpadding="0" width="100%"><tbody><tr> <td style="BORDER-LEFT-COLOR: #d4d0c8; BORDER-BOTTOM-COLOR: #d4d0c8; BORDER-TOP-COLOR: #d4d0c8; BACKGROUND-COLOR: transparent; BORDER-RIGHT-COLOR: #d4d0c8"> <div> <p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt"><font size="3"><span lang="EN-US" style="FONT-FAMILY: 宋体">2 </span><span style="FONT-FAMILY: 宋体">登陆</span></font></p> </div> </td> </tr></tbody></table></textbox></shape><shape id="_x0000_s1050" style="LEFT: 2962px; WIDTH: 1619px; POSITION: absolute; TOP: 6485px; HEIGHT: 360px" stroked="f" type="#_x0000_t202"><textbox inset="5.85pt,.7pt,5.85pt,.7pt"><table cellspacing="0" cellpadding="0" width="100%"><tbody><tr> <td style="BORDER-LEFT-COLOR: #d4d0c8; BORDER-BOTTOM-COLOR: #d4d0c8; BORDER-TOP-COLOR: #d4d0c8; BACKGROUND-COLOR: transparent; BORDER-RIGHT-COLOR: #d4d0c8"> <div> <p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt"><font size="3"><span lang="EN-US" style="FONT-FAMILY: 宋体">3.1</span><span style="FONT-FAMILY: 宋体">登陆成功</span></font></p> </div> </td> </tr></tbody></table></textbox></shape><group id="_x0000_s1051" style="LEFT: 5842px; WIDTH: 1440px; POSITION: absolute; TOP: 4145px; HEIGHT: 1440px" coordsize="1440,1440" coordorigin="5842,4145"><line id="_x0000_s1052" style="POSITION: absolute; flip: y" from="5842,4145" to="5842,5585"><font size="3"></font></line><line id="_x0000_s1053" style="POSITION: absolute" from="5842,4145" to="7282,4145"><stroke endarrow="block"><font size="3"></font></stroke></line></group><shape id="_x0000_s1054" style="LEFT: 5662px; WIDTH: 1260px; POSITION: absolute; TOP: 3605px; HEIGHT: 360px" stroked="f" type="#_x0000_t202"><textbox inset="5.85pt,.7pt,5.85pt,.7pt"><table cellspacing="0" cellpadding="0" width="100%"><tbody><tr> <td style="BORDER-LEFT-COLOR: #d4d0c8; BORDER-BOTTOM-COLOR: #d4d0c8; BORDER-TOP-COLOR: #d4d0c8; BACKGROUND-COLOR: transparent; BORDER-RIGHT-COLOR: #d4d0c8"> <div> <p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt"><font size="3"><span lang="EN-US" style="FONT-FAMILY: 宋体">3.2</span><span style="FONT-FAMILY: 宋体">登陆失败</span></font></p> </div> </td> </tr></tbody></table></textbox></shape></group><shape id="_x0000_s1055" style="LEFT: 5122px; WIDTH: 1621px; POSITION: absolute; TOP: 5944px; HEIGHT: 541px" stroked="f" type="#_x0000_t202"><textbox style="mso-next-textbox: #_x0000_s1055" inset="5.85pt,.7pt,5.85pt,.7pt"><table cellspacing="0" cellpadding="0" width="100%"><tbody><tr> <td style="BORDER-LEFT-COLOR: #d4d0c8; BORDER-BOTTOM-COLOR: #d4d0c8; BORDER-TOP-COLOR: #d4d0c8; BACKGROUND-COLOR: transparent; BORDER-RIGHT-COLOR: #d4d0c8"> <div> <p class="MsoNormal" style="MARGIN: 0cm 0cm 0pt"><span lang="EN-US" style="FONT-FAMILY: 宋体"><font size="3">LoginAction</font></span></p> </div> </td> </tr></tbody></table></textbox></shape></group></p> <wrap type="none"></wrap><anchorlock></anchorlock></group>

第二节 使用maven建立基本开发结构

使用如下命令建立Struts2 应用程序框架结构

mvn archetype:create

-DgroupId=com.jpleasure

-DartifactId=login

-DarchetypeGroupId=org.apache.struts -DarchetypeArtifactId=struts2-archetype-starter

-DarchetypeVersion=<chsdate w:st="on" year="1899" month="12" day="30" islunardate="False" isrocdate="False">2.0.5</chsdate>-SNAPSHOT -DremoteRepositories=http://people.apache.org/repo/m2-snapshot-repository

目录说明

生成的Struts2开发框架目录满足一般的maven项目，主要由以下目录组成：

src

├─main 源代码目录

│ ├─java java代码

│ ├─resources 资源文件等

│ └─webapp Web目录

│ ├─jsp JSP目录

│ ├─styles CSS目录

│ └─WEB-INF WEB-INF目录

└─test 测试代码目录

├─java java代码

└─resources 资源文件等

重要文件：

src\main\resources

applicationContext.xml Spring配置文件

log4j.properties log4j配置文件

struts.properties struts参数文件

struts.xml struts配置文件

xwork-conversion.properties xwork参数文件

src\main\webapp\WEB-INF

decorators.xml

dwr.xml DWR配置文件

sitemesh.xml SiteMesh配置文件

web.xml Web部署描述文件

进入工程目录（login目录）使用如下命令建立Eclipse工程文件

mvn eclipse:eclipse

使用如下命令打包工程

mvn package

应用程序打包完成之后可以再login\target目录中看到login.war文件，这个文件就是最终的成果文件

使用如下命令运行应用程序

mvn jetty:run

也可以将login.war拷贝到tomcat的webapps目录下来运行struts2应用程序。

打开IE在浏览器中输入：

http://localhost:8080/login

可以看到如下画面

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说明自动生成的框架已经可以运行。

第三节 补充Login功能

下面我们来完成login功能

首先将login工程导入到Eclipse中

之后建立在src\main\java目录中建立LoginAction类，代码清单如下：

package com.jpleasure.login.action;

import javax.servlet.http.HttpSession;

import com.opensymphony.xwork2.ActionSupport;

import org.apache.struts2.ServletActionContext;

public class LoginAction extends ActionSupport {

private String name;

private String password;

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public String getPassword() {

return password;

}

public void setPassword(String password) {

this.password = password;

}

public String forward() throws Exception {

return SUCCESS;

}

@Override

public String execute() throws Exception {

if("admin".equals(name)) {

HttpSession session = ServletActionContext.getRequest().getSession();

session.setAttribute("name", name);

return SUCCESS;

} else {

return INPUT;

}

}

}

Action具有以下特点：

1 从ActionSupport继承而来。

2 包含一些属性和getter，setter方法，这些属性用来保存客户端传递到服务器的数据，或者用来作为在JSP上显示的数据的源。

3 有一些返回String类型，无参数的方法，在LoginAction中是execute方法forwardLogin方法，这些方法就是Action需要执行的方法。

SUCCESS和INPUT都在com.opensymphony.xwork2.Action类中定义，类型为String，分别用来表示成功和输入结果。

在src\main\webapp中建立Welcome.jsp和Login.jsp两个JSP文件

Welcome.jsp代码清单如下：

<%@ page language="java" contentType="text/html; charset=UTF-8"

pageEncoding="UTF-8"%>

<%@taglib prefix="s" uri="/struts-tags" %>

<!DOCTYPE html PUBLIC "-//W<chmetcnv w:st="on" unitname="C" sourcevalue="3" hasspace="False" negative="False" numbertype="1" tcsc="0">3C</chmetcnv>//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

<title>Welcome</title>

</head>

<body>

<s:url action="forwardLogin" id="forwardLoginUrl"></s:url>

<s:a href="%{forwardLoginUrl}">Forward Login</s:a>

<%

if(session.getAttribute("name") != null){

out.println("<br/> login success.");

}

%>

</body>

</html>

Login.jsp 代码清单如下：

<%@ page language="java" contentType="text/html; charset=UTF-8"

pageEncoding="UTF-8"%>

<%@taglib prefix="s" uri="/struts-tags" %>

<!DOCTYPE html PUBLIC "-//W<chmetcnv w:st="on" unitname="C" sourcevalue="3" hasspace="False" negative="False" numbertype="1" tcsc="0">3C</chmetcnv>//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

<title>Login</title>

</head>

<body>

<s:url action="login" id="loginUrl"></s:url>

<s:form action="%{loginUrl}">

<s:textfield label="Name" name="name"/>

<s:password label="Password" name="password" />

<s:submit></s:submit>

</s:form>

</body>

</html>

这些JSP有如下特点：

1 有一个特殊的taglib声明，<%@taglib prefix="s" uri="/struts-tags" %>这是struts2的标准taglib声明。

2 一些s标签

<s:url action="forwardLogin" id="forwardLoginUrl"></s:url>定义了一个叫做forwardLoginUrl的指向forwardLogin的Action的路径。

同理：<s:url action="login" id="loginUrl"></s:url>定义了一个叫做loginUrl指向loginaction的Action的路径。

<s:a href="%{forwardLoginUrl}">Forward Login</s:a>定义了一个指向forwardLogin的链接，其中href使用了上面定义的内容。

<s:form action="%{loginUrl}">

<s:textfield label="Name" name="name"/>

<s:password label="Password" name="password" />

<s:submit></s:submit>

</s:form>

定义了一个向login Action提交的form，这个Form提交name和password两个字段，这个Form的action指向使用了前面定义的loginUrl变量。

配置src\main\resources\struts.xml 文件

在默认的package中添加如下内容

<package name="myPackage" extends="struts-default">

<!-- login begin -->

<action name="forwardLogin" method="forward"

class="com.jpleasure.login.action.LoginAction">

<result>/Login.jsp</result>

</action>

<action name="login" class=