Struts2学习笔记（1）----用户登录的实现
今天开始学习Struts2，用的教材是李刚的《Struts2.1权威指南》，刚学习，就碰到了不少麻烦，特在此记录下来，以备后用。
（1）首先，去http://struts.apache.org 下载struts2的完整版，解压后有很多jar包
（2）在MyEclipse中新建一个WebProject，特别要注意，在创建新Project时，会要求你选择J2EE Specification Level，默认的是J2EE1.4，要选择Jave EE 5.0才可以
（3）导入jar包。在工程名上点右键，选择Build Path,Configure Build Path,Libraries,Add External Jars,导入必须的类库
开始时，我按照书上所述，只导入了struts2-core-2.2.1.jar,xwork-core-2.2.1.jar,ognl-3.0.jar这三个包，但部署在Tomcat上之后，网站却启动不了，Running显示false，点击Start后，提示“FAIL - Application at context path /TestStruts could not be started ”，在网上搜了下，说可能是缺少必要的类库，于是，我仿照另一个project，导入了其他几个包，重新部署后，网站便正常启动了。
Referenced Libraries里是我导入的jar包，整个工程的文档结构如下图：
（4）配置文件：struts.xml
View Code
<?
xml version="1.0" encoding="UTF-8"
?>
<!
DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.2.dtd"
>
<
struts
>
<
package
name
="strutsqs"
extends
="struts-default"
>
<
action
name
="login"
class
="com.jp.action.LoginAction"
>
<
result
name
="error"
>
/error.jsp
</
result
>
<
result
name
="success"
>
/welcome.jsp
</
result
>
</
action
>
</
package
>
</
struts
>
web.xml
View Code
<?
xml version="1.0" encoding="UTF-8"
?>
<
web-app
version
="2.5"
xmlns
="http://java.sun.com/xml/ns/javaee"
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"
>
<
welcome-file-list
>
<
welcome-file
>
login.jsp
</
welcome-file
>
</
welcome-file-list
>
<
filter
>
<
filter-name
>
struts2
</
filter-name
>
<
filter-class
>
org.apache.struts2.dispatcher.FilterDispatcher
</
filter-class
>
</
filter
>
<
filter-mapping
>
<
filter-name
>
struts2
</
filter-name
>
<
url-pattern
>
/*
</
url-pattern
>
</
filter-mapping
>
</
web-app
>
login.jsp
View Code
<%
@ page language
=
"
java
"
import
=
"
java.util.*
"
pageEncoding
=
"
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
>
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</
head
>
<
body
>
<
form
action
="login.action"
method
="post"
>
<
table
align
="center"
>
<
caption
>
<
h3
>
用户登录
</
h3
>
</
caption
>
<
tr
>
<
td
>
用户名:
<
input
type
="text"
name
="username"
/>
</
td
>
</
tr
>
<
tr
>
<
td
>
密
码:
<
input
type
="password"
name
="password"
/>
</
td
>
</
tr
>
<
tr
align
="center"
>
<
td
colspan
="2"
>
<
input
type
="submit"
value
="登录"
/>
<
input
type
="reset"
value
="重置"
/>
</
td
>
</
tr
>
</
table
>
</
form
>
</
body
>
</
html
>
welcome.jsp
View Code
<%
@ page language
=
"
java
"
import
=
"
java.util.*
"
pageEncoding
=
"
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 'welcome.jsp' starting page
</
title
>
<
meta
http-equiv
="pragma"
content
="no-cache"
>
<
meta
http-equiv
="cache-control"
content
="no-cache"
>
<
meta
http-equiv
="expires"
content
="0"
>
<
meta
http-equiv
="keywords"
content
="keyword1,keyword2,keyword3"
>
<
meta
http-equiv
="description"
content
="This is my page"
>
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</
head
>
<
body
>
欢迎，${sessionScope.user}，你已经成功登录
<
br
>
</
body
>
</
html
>
LoginAction.java
View Code
package
com.jp.action;
import
javax.servlet.http.HttpServletRequest;
import
javax.servlet.http.HttpSession;
import
org.apache.struts2.ServletActionContext;
import
com.opensymphony.xwork2.Action;
import
com.opensymphony.xwork2.ActionContext;
//
实现了Action接口
public
class
LoginAction
implements
Action{
private
String username;
private
String password;
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;
}
public
String execute()
throws
Exception {
if
(getUsername().equals(
"
jp
"
)
&&
getPassword().equals(
"
jp
"
)) {
//
通过ActionContext对象访问Web应用的HTTP Session
ActionContext.getContext().getSession().put(
"
user
"
, username);
//
使用了Action接口中定义的SUCCESS、ERROR常量
return
SUCCESS;
}
else
return
ERROR;
}
}