登录系统-基于struts2的分层架构

1.下载支持Netbeans7.0的Struts2插件，在工具-插件-已下载-添加插件菜单下安装struts2插件。
2.新建一个web项目，在步骤4中选择struts2选项，去掉“Create example page”选项：


 
在自动生成web.xml中，给出了struts2过滤器配置，默认拦截所有请求：“\*”,
<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>
改成只拦截“*.action”和“*.jsp”,即只对struts和jsp文件拦截：
<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>*.action</url-pattern>        
    </filter-mapping>
    <filter-mapping>
        <filter-name>struts2</filter-name>        
        <url-pattern>*.jsp</url-pattern>
    </filter-mapping>
在自动生成的struts.xml文件（位于缺省包中）里，加入如下代码：
<package name="book" extends="struts-default">
        <action name="UserAction" class="book.action.UserAction">
            <result name="msg">/index.jsp</result>
        </action>
</package>
表示凡是经过struts2过滤的名为“UserAction”的action，均执行“book.action.UserAction”类程序，根据结果转向“index.jsp”页面。
3.创建如图所示的包结构：


 
4.在“bbok.common”包放置工具类用于数据库连接，在此添加DB_Conn.java文件：
package book.common;
 
import java.io.PrintWriter;
import java.sql.*;
 
public class DB_Conn { 
    private  String driverName="com.mysql.jdbc.Driver";  //驱动程序名
    private  String userName="root";                   //数据库用户名
    private  String userPwd="123456";                        //密码
    private  String url="jdbc:mysql://localhost:3306/book";   //连接字符串
    private  Connection conn=null;                  //数据库连接对象
    public Statement sm=null;                       //数据库语句对象
    private PrintWriter out = null;
    
    // 建立数据库连接
    public void ConnectDB(){
            try {
                   Class.forName(driverName).newInstance();
               conn=DriverManager.getConnection(url,userName,userPwd);  //获得数据库连接
                sm=conn.createStatement();
         } catch(Exception e) {
                out.print("数据库连接失败!");
            }
    }
    
    public void CloseDB(){
           try {
                     if (sm != null) {
                            sm.close();
                     }
                     conn.close();
              } catch (SQLException SqlE) {
                     out.print("数据库关闭失败！");
              }
    
   }
}
5.包“book.model”放置实体类，在此添加user.java文件：
       package book.model;
 
public class User {
       private String username;
       private String password;       
       
       public String getUsername() {                   //用户名称
              return username;
       }
       public void setUsername(String username) {
              this.username = username;
       }
       
       public String getPassword() {                   //登陆密码
              return password;
       }
       public void setPassword(String password) {
              this.password = password;
       }
       
}
6.包“book.idao”放置数据访问接口，添加IUserDao接口文件：
package book.idao;
import book.model.User;
public interface IUserDao {
    User fineOne(String userName,String userPassword);
}
7. 包“book.dao”放置数据访问类，添加UserDao.java文件，实现IUserDao接口，完成数据访问：
package book.dao;
 
import book.common.DB_Conn;
import book.model.User;
import book.idao.IUserDao;
import java.sql.ResultSet;
import java.sql.SQLException;
 
public class UserDao implements IUserDao{
       
    //创建公用数据库连接类对象
    DB_Conn db_conn=new DB_Conn(); 
    //通过用户名称获取用户信息
    @Override
    public User fineOne(String username, String password) {
       db_conn.ConnectDB();
       ResultSet rs = null;
       try {
            String sql = "select * from admin where u_Name ='"
                     + username + "' and u_Pass='" + password + "'";
            rs = db_conn.sm.executeQuery(sql);        // 执行sql语句
            User user = null;
            if (rs.next()) {
                user = new User();                      
              user.setUsername(username);
              user.setPassword(rs.getString("u_Pass"));                        
              return user;
            }
            return user;
        }catch (SQLException SqlE) {
            return null;
        }catch (Exception E) {
            return null;
       }finally {
            // 关闭连接，释放数据库资源：
            db_conn.CloseDB();
       }
    }     
}
8.在包“book.iservice”中放置数据的逻辑访问接口，在此添加IUserService.java接口文件：
package book.iservice;
import book.model.User;
public interface IUserService {
    User findUserByNameAndPassword(String userName,String userPassword);
}
9. 包“book.service”放置数据逻辑访问类，添加UserService.java文件，实现IUserService，调用UserDao类的功能，完成对数据逻辑访问：
package book.service;
import book.iservice.IUserService;
import book.model.User;
import book.idao.IUserDao;
import book.dao.UserDao;
public class UserService implements IUserService{
    private IUserDao userDao=new UserDao();
    @Override
    public User findUserByNameAndPassword(String userName,String userPassword){
        return userDao.fineOne(userName, userPassword);
    }    
}
10.在“book.action”包中放置action类，以实现对系统的控制，在此添加UserAction.java文件，该action类调用数据的逻辑访问类UserService实现对数据库的查询，根据查询结果构造不同的字符串：
package book.action;
import com.opensymphony.xwork2.ActionContext;
import book.iservice.IUserService;
import book.service.UserService;
import book.model.User;
public class UserAction {
    private IUserService userService=new UserService();
    private String userName;
    private String userPassword;
    private String msg;
    public String execute()throws Exception{
        User user=userService.findUserByNameAndPassword(userName, userPassword);
        if(user!=null){
            msg="登录成功！"+user.getUsername();
            ActionContext.getContext().getSession().put("user",user);
        }else{
            msg="登录失败！<a href=\"JavaScript:window.history.back()\">返回</a>";
        }
        return "msg";
    }
    public void setUserName(String userName){
        this.userName=userName;
    }
    public void setUserPassword(String userPassword){
        this.userPassword=userPassword;
    }
    public String getMsg(){
        return msg;
    }
}
11. 创建如下两个页面：
Login.jsp:
<%@ page pageEncoding="gb2312" %>
<%@ page contentType="text/html; charset=gb2312" %>
<% request.setCharacterEncoding("gb2312"); %>
<%@ page language="java" %>
<html>   
         <head><title>登录网页</title></head>
       <body>
       <form method="POST" action="UserAction.action">
 
       <table  >
           <tr>
             <td width="890" align="left" colspan="2">
              <b><font size="5">系统登录</font></b>
               <hr>
             </td>
           </tr>
            <% if (request.getAttribute("error") != null){ %>
       <tr>
              <td width=100% align=center colspan=4 height=36>
                   <font color=red><b><%=request.getAttribute("error")%></b></font>
              </td>
       </tr>
       <%
     }
       %>
           <tr>
             <td width="75" align="center">
               <p align="right">账号：</p>
             </td>
             <td width="809" align="center">
               <p align="left">
                <input type="text" name="userName" size="20"></td>
           </tr>
           <tr>
             <td width="75" align="center">
               <p align="right">密码：</p>
             </td>
             <td width="809" align="center">
               <p align="left">
               <input type="password" name="userPassword" size="20">
               <input type="submit" value="登录" name="loginButton"></td>
           </tr>
         </table>
       </form>
       </body>
       </html>
在这个页面中，下面的form标记语句：
<form method="POST" action="UserAction.action">
表示该页面提交一个名为："UserAction"的action，注意和struts.xml文件中的action的name相对应。
index.jsp:
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>显示信息</title>
    </head>
    <body>
        <h1>Hello World!</h1>
        <div id="content">
            <center>
                <br/><%=request.getAttribute("msg")%>
            </center>
        </div>
    </body>
</html>
该页面的标记语句：
<%=request.getAttribute("msg")%>
表示接收来自action的msg字符串。
12. 生成项目，并运行http://localhost:8080/login/login.jsp