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【J2EE核心开发学习笔记 010】struts2的搭建及连接数据库实现用户注册与登录

2016-05-28 14:13 1206 查看
搭建struts2是重点,搭建这个框架有些麻烦,遇到不少的问题,终于一一解决,写在此处,以作备忘。

1. 首先要下载struts2的一些组件,我下载的版本是struts-2.3.28.1,MyEclipse是Version: 2014版本的。由于版本的不断升级,导致在搭建的过程中,和过去相对较旧的版本搭建有了一些差别,不过问题不是很大。这里是下载的struts2的地址:http://struts.apache.org/download.cgi#struts25

2. 解压下载的组件我们可以看到这样的目录,



apps中是struts2自带的例子,docs是struts2的参考文档,lib是struts2所有的组件jar包,src是struts2的源代码。我们打开apps解压struts2-blank.war,在解压的struts2-blank\WEB-INF\lib文件中找到以下组件,



另外由于我们需要连接数据库所以找一个连接mysql的jar,我这里用的是mysql-connector-java-5.1.13-bin.jar,新建一个web项目,将这些组件复制到建立的web工程下的WEB-INF/lib目录中,这些组件其实就是编译好的类文件。

3. 配置web.xml文件,这也是很关键的一步,在启动服务器时,服务器要根据这个文件去进行初始化。而struts2和struts1启动有很大的不同,它是通过过滤器来启动的,而struts1是通过加载servlet来启动的,故web.xml的配置内容如下。

<?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/j2ee" xmlns:web="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd" id="WebApp_9" version="2.4">
<display-name>Struts Blank</display-name>
<filter>
<filter-name>struts2</filter-name>
<filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<welcome-file-list>
<welcome-file>login.jsp</welcome-file>
</welcome-file-list>
</web-app>


4. 接下来就是配置struts.xml文件。这个文件就好像起着一个过滤器的作用,用户发来的请求要经过该文件的过滤,根据用户请求中所请求的处理类型,来选择相应的处理逻辑。我们这里的struts.xml文件配置如下:

<?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>

<package name="backed" namespace="/backed" extends="struts-default">
<action name="login" class="com.struts2_test.action.UserAction" method="login">
<result name="loginout">/error.jsp</result>
<result name="loginin">/welcome.jsp</result>
</action>
<action name="regist" class="com.struts2_test.action.UserAction" method="regist">
<result name="error">/error.jsp</result>
<result name="success">/welcome.jsp</result>
</action>
</package>

</struts>


在struts.xml中,是采用package来管理各种action的。package标签中的namespace指定了该包的命名空间。extends是说当前这个包继承自struts-default包,可以在struts2-core-2.3.28.1.jar中的struts-default.xml文件中找到这个包,这个包被定义成抽象的,它不能包含有action。包中的每一个action标签都和一个逻辑处理类进行了映射,name指定了这个action的名字,和包的namespace组合起来,可以直接访问这个逻辑处理类。class指定了逻辑处理类的位置,method指定了进行逻辑处理类中进行逻辑处理的方法,这个execute很重要,而且它有固定的返回类型,就是String。result标签就是根据逻辑判断之后,execute方法返回的字符串,根据返回的字符串,来进入到指定的页面。这里一定要把跳转的地址写清楚,明白。否则浏览器会报404的错误。

5. 根据struts.xml的配置, 我们需要在WebRoot目录下建立四个jsp页面分别为regist.jsp, login.jsp, welcome.jsp和error.jsp。在src目录下建立两个java类文件Dao.java和UserAction.java。其中需要注意UserAction继承自ActionSupport这个类。

项目的目录结构为:



它们的源码为:

regist.jsp:

<%@ 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 'regist.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>

<center>
<form action="backed/regist" method="post">
<table>
<caption><h2>用户注册</h2></caption>
<tr>
<td>username: </td>
<td><input type="text" name="username" /></td>
</tr>
<tr>
<td>password: </td>
<td><input type="password" name="password" /></td>
</tr>
<tr>
<td><input type="submit" name="submit" /></td>
</tr>
</table>
</form>
</center>

</body>
</html>


login.jsp:

<%@ 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 'login.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>

<form action="backed/login" method="post">
<table align="center">
<caption><h2>用户登录</h2></caption>
<tr>
<td>用户名:<input type="text" name="username" /></td>
</tr>
<tr>
<td>密码: <input type="text" name="password"/></td>
</tr>
<tr align="center">
<td colspan="2"><input type="submit"/></td>
</tr>
</table>
</form>

</body>
</html>


welcome.jsp:

<%@ 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>
<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>
您已经执行成功! <br>
</body>
</html>


error.jsp:

<%@ 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 'error.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>
执行失败!! <br>
</body>
</html>


Dao.java:

package com.struts2_test.dao;

import java.sql.*;
public class Dao {

Connection con = null;
Statement stat = null;
ResultSet rs = null;

public Dao() {
try {
Class.forName("com.mysql.jdbc.Driver");
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/struts2_test","root","root");
stat = con.createStatement();
} catch (Exception e) {
// TODO: handle exception
con = null;
}
}

public ResultSet executeQuery(String sql) {
try {
rs = stat.executeQuery(sql);
} catch (Exception e) {
// TODO: handle exception
rs = null;
}
return rs;
}

public int executeUpdate(String sql) {
try {
stat.executeUpdate(sql);
return 0;
} catch (Exception e) {
// TODO: handle exception
}
return -1;
}

}


UserAction.java:

package com.struts2_test.action;

import com.opensymphony.xwork2.ActionSupport;
import com.struts2_test.dao.Dao;

import java.sql.*;

public class UserAction extends ActionSupport {

private Dao dao = new Dao();
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 login() {
String sql = "select * from tb_user where t_userName='" + getUsername()+"' and t_userPassword ='"+getPassword()+"'";
ResultSet rS = dao.executeQuery(sql);
try {
if (rS.next()) {
return "loginin";
}
return "loginout";
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return "loginout";
}
}

public String regist() {
String sql = "insert into tb_user(t_userName,t_userPassword,t_isCheck) values('"+getUsername()+"','"+getPassword()+"','0')";
int i = dao.executeUpdate(sql);
if (i > -1) {
return "success";
}
return "error";
}
}


最后看一下我们数据库struts2_test:



经过这几步后,启动你的服务器,在地址栏输入登录界面的地址,一个简单的struts2框架就搭建好了。

csdn下载:http://download.csdn.net/detail/davebobo/9533847
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