第一个纯servlet MVC开发用户管理系统总结



MVC 原意就是 数据模型（modle）、视图（view）、控制器（controller）

• 
  
• 每张表都有一个数据类（modle类  内含对属性的操作方法（get和set））、一个service方法和一个控制器与之相对应，在写项目的时候尽量把对一类事务（增删改）的操作放在一个控制器内。下面的项目我把增删改查  全部放在了一个控制器内。

  
  

  在该项目中，涉及一个表的操作，所以我就写了一个控制器（UserClServlet），对表的增删改查都在该控制器内。各个view页面通过传递一个参数type给控制器来辨别是属于哪种操作，再近一步做对数据的处理。对数据库的所有操作都在UsersService里面，控制器通过调用UsersService里面的方法来完成对数据库的增删改查操作。
  
  
  首先创建了一个User类  并生成设置和改变属性的方法    代码如下：
          package com.mxf.domain;
  
  public class Users {
      String name;
      String password;
      int id;
      public int getId() {
          return id;
      }
      public void setId(int id) {
          this.id = id;
      }
      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;
      }
      
  }
  
  
  然后为该类提供了service方法，包括 增删改查 和分页的部分方法
  代码如下：
          package com.mxf.service;
  
  import java.sql.ResultSet;
  import java.sql.SQLException;
  import java.util.ArrayList;
  import com.mxf.domain.Users;
  import com.mxf.util.SQLUtil;
  public class UsersService {
      
      //增加
      public boolean AddUser(Users user)
      {
          boolean flag = true;
          
          String sql = "insert into user values (?,?,?)";
          String []parameters ={user.getId()+"",user.getName(),user.getPassword()};
          try {
              SQLUtil.executeUpdate(sql, parameters);
          } catch (Exception e) {
              // TODO: handle exception
              flag = false;
          }
          return flag;
      }
      
      
      public Users getUserById (String id)
      {
          Users users = new Users();
          String sql = "select * from user where id=?";
          String []parameters = {id};
          ResultSet rs = SQLUtil.executeQuery(sql, parameters);
          try {
              if(rs.next())
              {
                  users.setId(rs.getInt(1));
                  users.setName(rs.getString(2));
                  users.setPassword(rs.getString(3));
              }
          } catch (SQLException e) {
              // TODO Auto-generated catch block
              e.printStackTrace();
          }finally{
              SQLUtil.close(SQLUtil.getConn(), SQLUtil.getPs(), rs);
          }
          
          return users;
      }
      
      //修改
      public boolean UpdateUsers(Users users)
      {
          boolean flag = true;
          
          String sql = "UPDATE USER SET userName=?,userpwd=? WHERE id=?";
          String []parameters = {users.getName(),users.getPassword(),users.getId()+""};
          
          try {
              SQLUtil.executeUpdate(sql, parameters);
          } catch (Exception e) {
              // TODO: handle exception
              flag=false;
          }
          
          return flag;
      }
      
      //删除
      public boolean delectUsers(String id)
      {
          boolean flag = true;
          
          String sql = "delete from user where id=?";
          String []parameters = {id};
          
          try {
              SQLUtil.executeUpdate(sql, parameters);
          } catch (Exception e) {
              // TODO: handle exception
              flag = false;
          }
          return flag;
      }
      //验证
      public boolean checkUsers(Users users)
      {
          boolean flag = false;
          String sql = "select * from user where userName=? and userpwd=?";
          String [] parameters = {users.getName(),users.getPassword()};
          ResultSet rs = SQLUtil.executeQuery(sql, parameters);
          try {
              if(rs.next())
              {
                  flag = true;
              }
          } catch (SQLException e) {
              // TODO Auto-generated catch block
              e.printStackTrace();
          }finally{
              SQLUtil.close(SQLUtil.getConn(), SQLUtil.getPs(), rs);
          }
          return flag;
      }
      
      //分页实现
      public ArrayList getUsersByPage(int pageNow,int pageSize)
      {
          ArrayList<Users> arrayList = new ArrayList<Users>();
          String sql = " SELECT * FROM  USER ORDER BY id LIMIT "+(pageNow-1)*pageSize+","+pageSize+"";
          ResultSet rs=SQLUtil.executeQuery(sql, null);
          try {
              while(rs.next())
              {
                  Users u = new Users();
                  u.setId(rs.getInt(1));
                  u.setName(rs.getString(2));
                  u.setPassword(rs.getString(3));
                  arrayList.add(u);
              }
              
          } catch (SQLException e) {
              // TODO Auto-generated catch block
              e.printStackTrace();
          }finally{
              SQLUtil.close(SQLUtil.getConn(), SQLUtil.getPs(), rs);
          }
          
          return arrayList;
      }
      
      //分页 得到PageCount
      public int getPageCount(int pageSize)
      {
          int rowCount = 0;
          
          String sql = "select count(*) from user";
          ResultSet rs = SQLUtil.executeQuery(sql, null);
          try {
              rs.next();
              rowCount= rs.getInt(1);
          } catch (SQLException e) {
              e.printStackTrace();
          }finally{
              SQLUtil.close(SQLUtil.getConn(), SQLUtil.getPs(), rs);
          }
          
          return (rowCount-1)/pageSize + 1;
      }
      
      //查找
      public Users selectUserById(String id)
      {
          Users user = new Users();
          
          String sql = "select * from user where id=?";
          String [] parameters ={id};
          ResultSet rs = SQLUtil.executeQuery(sql, parameters);
          try {
              while(rs.next())
              {
                  user.setId(rs.getInt(1));
                  user.setName(rs.getString(2));
                  user.setPassword(rs.getString(3));
              }
          } catch (SQLException e) {
              // TODO Auto-generated catch block
              e.printStackTrace();
          }finally{
              SQLUtil.close(SQLUtil.getConn(), SQLUtil.getPs(), rs);
          }
          
          return user;
      }
  }
  
  
  接下来是控制器   主要负责 验证、增删改查的任务
  代码如下：
          package com.mxf.controller;
  
  import java.io.IOException;
  import java.io.PrintWriter;
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServlet;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import com.mxf.domain.Users;
  import com.mxf.service.UsersService;
  public class UserClServlet extends HttpServlet {
      public void doGet(HttpServletRequest request, HttpServletResponse response)
              throws ServletException, IOException {
          response.setContentType("text/html;charset=utf-8");
          request.setCharacterEncoding("utf-8");
          PrintWriter out = response.getWriter();
          String type = request.getParameter("type");
          UsersService usersService=new UsersService();
          if(type.equals("del"))
          {
              String id = request.getParameter("id");
              if(usersService.delectUsers(id))
              {
                  request.setAttribute("info", "删除");
                  request.getRequestDispatcher("/Ok").forward(request, response);
              }else
              {
                  request.setAttribute("info", "删除");
                  request.getRequestDispatcher("/Err").forward(request, response);
              }
          }else if(type.equals("gotoUpdate"))
          {
              String id = request.getParameter("id");
              Users users = usersService.getUserById(id);
              request.setAttribute("userinfo", users);
              request.getRequestDispatcher("/Update").forward(request, response);
          }else if(type.equals("update"))
          {
              String username = request.getParameter("username");
              String password = request.getParameter("password");
              String id = request.getParameter("id");
              Users users = new Users();
              users.setId(Integer.parseInt(id));
              users.setName(username);
              users.setPassword(password);
              if(usersService.UpdateUsers(users))
              {
                  request.setAttribute("info", "修改");
                  request.getRequestDispatcher("/Ok").forward(request, response);
              }else
              {
                  request.setAttribute("info", "修改");
                  request.getRequestDispatcher("/Err").forward(request, response);
              }
          }else if(type.equals("gotoAdd"))
          {
              request.getRequestDispatcher("/AddServletView").forward(request, response);
          }else if(type.equals("Add"))
          {
              String id = request.getParameter("id");
              String username = request.getParameter("username");
              String password = request.getParameter("password");
              
              Users user = new Users();
              user.setId(Integer.parseInt(id));
              user.setName(username);
              user.setPassword(password);
              if(usersService.AddUser(user))
              {
                  request.setAttribute("info", "添加");
                  request.getRequestDispatcher("/Ok").forward(request, response);
              }else
              {
                  request.setAttribute("info", "添加");
                  request.getRequestDispatcher("/Err").forward(request, response);
              }
          }else if(type.equals("selectUser"))
          {
              String id = request.getParameter("id");
              Users user = usersService.selectUserById(id);
              request.setAttribute("userInfo", user);
              request.getRequestDispatcher("/ResultServlet").forward(request, response);
          }else if(type.equals("LoginCheck"))
          {
              String username = request.getParameter("username");
              String password = request.getParameter("password");
              
              Users user = new Users();
              user.setName(username);
              user.setPassword(password);
              
              if(usersService.checkUsers(user))
              {
                  request.getRequestDispatcher("/MainFrame").forward(request, response);
              }else
              {
                  request.setAttribute("error", "您的用户名或密码错误!");
                  request.getRequestDispatcher("/LoginServlet").forward(request, response);
              }
          }
          
      }
      public void doPost(HttpServletRequest request, HttpServletResponse response)
              throws ServletException, IOException {
          this.doGet(request, response);
      }
  }
  
  
  下面是工具类（数据库的操作）
  代码如下：
          /**
  
   * sql工具类
   */
  package com.mxf.util;
  import java.sql.*;
  public class SQLUtil {
      private static Connection conn= null;
      private static PreparedStatement ps = null;
      private static ResultSet rs = null;
      
      private static String driver = "com.mysql.jdbc.Driver";
      private static String url = "jdbc:mysql://localhost:3306/test";
      private static String pwd = "root";
      private static String user = "root";
      
      static
      {
          try {
              Class.forName(driver);
          } catch (ClassNotFoundException e) {
              // TODO Auto-generated catch block
              e.printStackTrace();
          }
      }
      
      public static Connection getConnection()
      {
          try {
              conn = DriverManager.getConnection(url,user,pwd);
          } catch (SQLException e) {
              // TODO Auto-generated catch block
              e.printStackTrace();
          }
          
          return conn;
      }
      
      //统一的查询select
      public static ResultSet executeQuery(String sql,String [] parameters)
      {
          try {
              conn = getConnection();
              ps = conn.prepareStatement(sql);
              if(null!=parameters&&!parameters.equals(""))
              {
                  for(int i=0;i<parameters.length;i++)
                  {
                      ps.setObject(i+1,parameters[i]);
                  }
              }
              rs = ps.executeQuery();
              
          } catch (SQLException e) {
              e.printStackTrace();
          }finally{
              //关闭资源 在调用的最后关闭  现在关闭了   调用者取不到资源
              //close(conn, ps, rs);
          }
          
          return rs;
      }
      
      //执行一次的增、删、改
      public static void executeUpdate(String sql,String []parameters)
      {
          conn = getConnection();
          try {
              ps = conn.prepareStatement(sql);
              if(null != parameters && !parameters.equals(""))
              {
                  for(int i=0;i<parameters.length;i++)
                  {
                      ps.setObject(i+1, parameters[i]);
                  }
              }
               ps.executeUpdate();
          } catch (SQLException e) {
              // TODO Auto-generated catch block
              e.printStackTrace();
              throw new RuntimeException(e.getMessage());
          }finally{
              close(conn, ps, rs);
          }
      }
      
      public static void close(Connection conn,PreparedStatement ps,ResultSet rs)
      {
          if(null != rs)
          {
              try {
                  rs.close();
              } catch (SQLException e) {
                  // TODO Auto-generated catch block
                  e.printStackTrace();
              }
              rs = null;
          }
          
          if(null != ps)
          {
              try {
                  ps.close();
              } catch (SQLException e) {
                  // TODO Auto-generated catch block
                  e.printStackTrace();
              }
              ps = null;
          }
          
          if(null != conn)
          {
              try {
                  conn.close();
              } catch (SQLException e) {
                  // TODO Auto-generated catch block
                  e.printStackTrace();
              }
              conn = null;
          }
      }
      
      public static Connection getConn()
      {
          return conn;
      }
      
      public static PreparedStatement getPs()
      {
          return ps;
      }
      
      public static ResultSet getRs()
      {
          return rs;
      }
  }
  
  
  下面是各种页面 即view层  MVC 中的V
  
  
  登录界面：
          package com.mxf.view;
  
  import java.io.IOException;
  import java.io.PrintWriter;
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServlet;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  public class LoginServlet extends HttpServlet {
      
      public void doGet(HttpServletRequest request, HttpServletResponse response)
              throws ServletException, IOException {
          response.setContentType("text/html;charset=utf-8");
          PrintWriter out = response.getWriter();
          request.setCharacterEncoding("utf-8");
          
          out.println("<img src='images/4.jpg'/><hr>");
          out.println("<h1>用户登录<h1><br>");
          out.println("<form action='/UserManager3/UserClServlet?type=LoginCheck' method='post' >");
          out.println("用户名<input type='text' name='username'><br>");
          out.println("密码<input type='password' name='password'><br>");
          out.println("<input type='submit' value='提交'>");
          out.println(" </form>");
          String errorInfo = (String) request.getAttribute("error");
          
          if(null!=errorInfo)
          {
              out.println(errorInfo);
          }
          out.println("<hr>");
          out.println("<img src='images/5.jpg'/>");
          
          
          
          
      }
      
      public void doPost(HttpServletRequest request, HttpServletResponse response)
              throws ServletException, IOException {
          this.doGet(request, response);
      }
  }
  
  
  主界面：
          package com.mxf.view;
  
  import java.io.IOException;
  import java.io.PrintWriter;
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServlet;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  public class MainFrame extends HttpServlet {
      public void doGet(HttpServletRequest request, HttpServletResponse response)
              throws ServletException, IOException {
          response.setContentType("text/html;charset=utf-8");
          PrintWriter out = response.getWriter();
          request.setCharacterEncoding("utf-8");
          String username = request.getParameter("username");
          out.println("<img src='images/4.jpg'/>  欢迎 " + username + " 登录   " +
                  "<a href='/UserManager3/LoginServlet'>重新登录</a>");
          
          out.println("<hr>");
          out.println("<h3>请选择您的操作</h3><br>");
          out.println("<a href='/UserManager3/ManageUsers?username="+username+"'>管理用户</a><br>");
          out.println("<a href='/UserManager3/UserClServlet?type=gotoAdd'>添加用户</a><br>");
          out.println("<a href='/UserManager3/SelectServlet'>查询用户</a><br>");
          out.println("<a href='/UserManager3/LoginServlet'>安全退出</a>");
          
          out.println("<hr>");
          out.println("<img src='images/5.jpg'/>");
      }
      public void doPost(HttpServletRequest request, HttpServletResponse response)
              throws ServletException, IOException {
          this.doGet(request, response);
      }
  }
  
  
  用户管理界面 （显示多有用户并分页）
          package com.mxf.view;
  
  import java.io.IOException;
  import java.io.PrintWriter;
  import java.sql.Connection;
  import java.sql.DriverManager;
  import java.sql.PreparedStatement;
  import java.sql.ResultSet;
  import java.util.ArrayList;
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServlet;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import com.mxf.domain.Users;
  import com.mxf.service.UsersService;
  public class ManageUsers extends HttpServlet {
      
      public void doGet(HttpServletRequest request, HttpServletResponse response)
              throws ServletException, IOException {
          response.setContentType("text/html;charset=utf-8");
          request.setCharacterEncoding("utf-8");
          PrintWriter out = response.getWriter();
          String username=request.getParameter("username");
          out.println("<img src='images/4.jpg'/> " +
                  "<a href='/UserManager3/MainFrame?username="+username+"'>返回主界面</a>" +"  "+
                  "<a href='/UserManager3/LoginServlet'>  安全退出</a><hr> ");
          out.println("<h3>管理用户</h3>");
          
          //分页
          int pageNow = 1;    //表示第几页
          int pageSize = 5;   //表示每页显示几行
          int pageCount = 0;   //表示共有多少页
          //接收超链接pageNow数据
          String spageNow = request.getParameter("pageNow");
          
          if(null!=spageNow)
          {
              pageNow = Integer.parseInt(spageNow);
          }
      
              UsersService usersService = new UsersService();
              pageCount = usersService.getPageCount(pageSize);
              ArrayList<Users> arrayList = usersService.getUsersByPage(pageNow, pageSize);
              out.println("<table border=1 width=500>");
              out.println("<tr><th>id</th><th>用户名</th><th>密码</th><th>删除用户</th><th>修改用户</th></tr>");
              for(Users users:arrayList)
              {
                  out.println("<tr><td>"+users.getId()+"</td><td>"+
                          users.getName()+"</td><td>"+users.getPassword()+"" +
                                  "</td><td><a href='/UserManager3/UserClServlet?type=del&id="+users.getId()+"'>删除用户</a></td><td>" +
                                  "<a href='/UserManager3/UserClServlet?type=gotoUpdate&id="+users.getId()+"'>修改用户</a></td></tr>");
              }
              out.println("</table>");
              
              out.print("<a href='/UserManager3/ManageUsers?pageNow="+(pageNow==1?pageNow:(pageNow-1))+"'>上一页</a>");
              
              for(int i=1;i<=pageCount;i++)
              {
                  out.print("<a href='/UserManager3/ManageUsers?pageNow="+i+"'><"+i+"></a>");
              }
              
              out.print("<a href='/UserManager3/ManageUsers?pageNow="+(pageNow==pageCount?pageNow:(pageNow+1))+"'>下一页</a>");
              
              out.println("   "+"当前页"+pageNow+"/"+"总页数"+pageCount);
              
          
          out.println("<hr><img src='images/5.jpg'/>");
          
      }
      
      public void doPost(HttpServletRequest request, HttpServletResponse response)
              throws ServletException, IOException {
          this.doGet(request, response);
      }
  }
  
  
  修改用户信息页面：
          package com.mxf.view;
  
  import java.io.IOException;
  import java.io.PrintWriter;
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServlet;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import com.mxf.domain.Users;
  public class Update extends HttpServlet {
      public void doGet(HttpServletRequest request, HttpServletResponse response)
              throws ServletException, IOException {
          response.setContentType("text/html;charset=utf-8");
          request.setCharacterEncoding("utf-8");
          PrintWriter out = response.getWriter();
          Users users = (Users) request.getAttribute("userinfo");
          out.println("<form action='/UserManager3/UserClServlet?type=update' method='post' >");
          out.println("<table border=1 width=500>");
          out.println("<tr><td>id</td><td><input type='text' readonly name='id' value='"+users.getId()+"'></td></tr>");
          out.println("<tr><td>用户名</td><td><input type='text' name='username' value='"+users.getName()+"'></td></tr>");
          out.println("<tr><td>密码</td><td><input type='text' name='password' value='"+users.getPassword()+"'></td></tr>");
          out.println("</table>");
          out.println("<input type='submit' value='修改' >");
          out.println("</form>");
      }
      public void doPost(HttpServletRequest request, HttpServletResponse response)
              throws ServletException, IOException {
          this.doGet(request, response);
      }
  }
  
  
  添加用户页面：
          package com.mxf.view;
  
  
  
  import java.io.IOException;
  import java.io.PrintWriter;
  
  
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServlet;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  
  public class AddServletView extends HttpServlet {
  
  
  public void doGet(HttpServletRequest request, HttpServletResponse response)
  throws ServletException, IOException {
  
  
  response.setContentType("text/html");
  PrintWriter out = response.getWriter();
  request.setCharacterEncoding("utf-8");
  out.println("<form action='/UserManager3/UserClServlet?type=Add' method='post' >");
  out.println("<table border=1 width=500>");
  out.println("<tr><td>id</td><td><input type='text'  name='id' ></td></tr>");
  out.println("<tr><td>用户名</td><td><input type='text' name='username' ></td></tr>");
  out.println("<tr><td>密码</td><td><input type='text' name='password' ></td></tr>");
  out.println("</table>");
  out.println("<input type='submit' value='添加' >");
  out.println("</form>");
  out.println("<a href='/UserManager3/MainFrame'>返回主界面 </a>" );
  }
  
  
  public void doPost(HttpServletRequest request, HttpServletResponse response)
  throws ServletException, IOException {
  
  
  this.doGet(request, response);
  }
  
  
  }
  
  
  查询用户页面：
          package com.mxf.view;
  
  import java.io.IOException;
  import java.io.PrintWriter;
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServlet;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  public class SelectServlet extends HttpServlet {
      
      public void doGet(HttpServletRequest request, HttpServletResponse response)
              throws ServletException, IOException {
          response.setContentType("text/html;charset=utf-8");
          PrintWriter out = response.getWriter();
          request.setCharacterEncoding("utf-8");
          out.println("<form action='/UserManager3/UserClServlet?type=selectUser' method='post' >");
          out.println("<tr><td>id</td><td><input type='text'  name='id' '></td></tr>");
          out.println("<input type='submit' value='查询' ><a href='/UserManager3/MainFrame'>返回主界面</a>" );
          out.println("</form>");
      }
      
      public void doPost(HttpServletRequest request, HttpServletResponse response)
              throws ServletException, IOException {
          this.doGet(request, response);
      }
  }
  
  
  查询后返回结果页面：
          package com.mxf.view;
  
  
  
  import java.io.IOException;
  import java.io.PrintWriter;
  
  
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServlet;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  
  import com.mxf.domain.Users;
  
  
  public class ResultServlet extends HttpServlet {
  
  
  public void doGet(HttpServletRequest request, HttpServletResponse response)
  throws ServletException, IOException {
  
  
  response.setContentType("text/html");
  PrintWriter out = response.getWriter();
  request.setCharacterEncoding("utf-8");
  Users users = (Users) request.getAttribute("userInfo");
  out.println("<table border=1 width=500>");
  out.println("<tr><td>id</td><td>"+users.getId()+"</td></tr>");
  out.println("<tr><td>用户名</td><td>"+users.getName()+"</td></tr>");
  out.println("<tr><td>密码</td><td>"+users.getPassword()+"</td></tr>");
  out.println("</table>");
  out.println("<a href='/UserManager3/MainFrame'>返回主界面 </a>");
  }
  
  
  public void doPost(HttpServletRequest request, HttpServletResponse response)
  throws ServletException, IOException {
  
  
  this.doGet(request, response);
  }
  
  
  }