jsp 实现修改和删除功能

main.jsp   实现查询 在此界面快捷方式到修改界面   

点击修改  会把数据传递到exit.jsp

修改   edit.jsp

前面数据：

数据库：

/*
 Navicat Premium Data Transfer

 Source Server         : c10.87.12.251
 Source Server Type    : SQL Server
 Source Server Version : 11002100
 Source Host           : 10.87.12.251:1433
 Source Catalog        : userdb
 Source Schema         : dbo

 Target Server Type    : SQL Server
 Target Server Version : 11002100
 File Encoding         : 65001

 Date: 19/06/2019 22:19:40
*/


-- ----------------------------
-- Table structure for userinfo
-- ----------------------------
IF EXISTS (SELECT * FROM sys.all_objects WHERE object_id = OBJECT_ID(N'[dbo].[userinfo]') AND type IN ('U'))
    DROP TABLE [dbo].[userinfo]
GO

CREATE TABLE [dbo].[userinfo] (
  [id] int IDENTITY(1,1) NOT NULL,
  [username] varchar(50) COLLATE Chinese_PRC_CI_AS NULL,
  [userpwd] varchar(50) COLLATE Chinese_PRC_CI_AS NULL,
  [sex] varchar(50) COLLATE Chinese_PRC_CI_AS NULL,
  [age] int NULL,
  [address] varchar(50) COLLATE Chinese_PRC_CI_AS NULL
)
GO

ALTER TABLE [dbo].[userinfo] SET (LOCK_ESCALATION = TABLE)
GO


-- ----------------------------
-- Records of [userinfo]
-- ----------------------------
SET IDENTITY_INSERT [dbo].[userinfo] ON
GO

INSERT INTO [dbo].[userinfo] ([id], [username], [userpwd], [sex], [age], [address]) VALUES (N'1', N'root', N'123', N'1', N'1', N'1')
GO

SET IDENTITY_INSERT [dbo].[userinfo] OFF
GO

（1）db/DbConn.java

package db;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class DbConn {

    public  static Connection  getConn()
    {
        Connection con =null;
        try {
            //    Class.forName("com.mysql.jdbc.Driver"); // 加载驱动程序
                Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");

            } catch (ClassNotFoundException e) {
                System.out.println("加载驱动程序错误" + e.getMessage());
            }
            
            try {
                // 创建连接 testdb是数据库名称
                 con = DriverManager.getConnection("jdbc:sqlserver://localhost:1433;DatabaseName=userdb", "sa", "123456");

            } catch (SQLException e) {

                System.out.println("数据库连接操作出错" + e.getMessage());
            }
        return con;
    }
}

（2）  po/User.java

package po;

public class User {
    int id;
    String username;
    String password;
    int age;
    String sex;
    String address;
    
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    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 int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public String getSex() {
        return sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }
    public String getAddress() {
        return address;
    }
    public void setAddress(String address) {
        this.address = address;
    }

}

（3）  dao/UserDAO.java

    //根据id 查找字段 返回给edit表
    public  User  getUser(int id)
    {
        User u=new User();
        try {
            // 创建连接 testdb是数据库名称
            Connection con =DbConn.getConn();
                // 创建声明SQL对象
            Statement stm = con.createStatement();
            // 执行SQL语句，得到结果集，结果集放到ResultSet对象中
            ResultSet rs = stm.executeQuery("select * from userinfo where id="+id);
            // 通过循环，从结果集对象中取得数据
            while (rs.next()) {
                
                String username = rs.getString("username"); // 取得字符类型的字段username的值，
                String userpwd = rs.getString("userpwd");
                String sex=rs.getString("sex");
                int age=rs.getInt("age");
                String address=rs.getString("address");
                
                  u.setId(id);
                  u.setUsername(username);
                  u.setPassword(userpwd);
                  u.setSex(sex);
                  u.setAge(age);
                  u.setAddress(address);
                 
            }
        } catch (SQLException e) {

            System.out.println("数据库操作出错" + e.getMessage());
        }
        return u;
    }
//插入新数据  根据id
    public int edit(User u)
    {
        int n=0;
        try {
            // 创建连接 testdb是数据库名称
          Connection con = DbConn.getConn();
            
            // 创建声明SQL对象
            Statement stm = con.createStatement();
            // 执行SQL语句，得到结果集，结果集放到ResultSet对象中
            String sql="update userinfo set username='"+u.getUsername()+"',userpwd='"+u.getPassword()+"',sex='"+u.getSex()+"',age="+u.getAge()+",address='"+u.getAddress()+"' " +
                    "where id="+u.getId()+"";
            n=stm.executeUpdate(sql);
        } catch (SQLException e) {

            System.out.println("数据库操作出错" + e.getMessage());
        }
        return n;
    }

public  List<User> getUserList()
    {
        List<User> ls=new ArrayList<User>();
        try {
            // 创建连接 testdb是数据库名称
            Connection con =DbConn.getConn();
                // 创建声明SQL对象
            Statement stm = con.createStatement();
            // 执行SQL语句，得到结果集，结果集放到ResultSet对象中
            ResultSet rs = stm.executeQuery("select * from userinfo");
            // 通过循环，从结果集对象中取得数据
            while (rs.next()) {
                int id = rs.getInt("id"); // 取得int类型的字段id的值，
                String username = rs.getString("username"); // 取得字符类型的字段username的值，
                String userpwd = rs.getString("userpwd");
                String sex=rs.getString("sex");
                int age=rs.getInt("age");
                String address=rs.getString("address");
                User u=new User();
                  u.setId(id);
                  u.setUsername(username);
                  u.setPassword(userpwd);
                  u.setSex(sex);
                  u.setAge(age);
                  u.setAddress(address);
                  ls.add(u);
            }
        } catch (SQLException e) {

            System.out.println("数据库操作出错" + e.getMessage());
        }
        return ls;
    }

    public boolean login(String username,String userpwd)
    {
         boolean flag=false;
        try {
            // 创建连接 testdb是数据库名称
            Connection con = DbConn.getConn();
            // 创建声明SQL对象
            Statement stm = con.createStatement();
            // 执行SQL语句，得到结果集，结果集放到ResultSet对象中
            ResultSet rs = stm.executeQuery("select * from userinfo where username='"+username+"' and userpwd='"+userpwd+"' ");
            // 通过循环，从结果集对象中取得数据
            if(rs.next()) {
                flag=true;
            }
            else
            {
               flag=false;
            }

        } catch (SQLException e) {

            System.out.println("数据库操作出错" + e.getMessage());
        }
        return flag;
    }

（4）servlet

main里面的 <td><a href="servlet/GetUserServlet?userid=<%=u.getId()%>">修改</a></td>  调用  GetUserServlet   调用UserDAO. getUser(int id)  方法

GetUserServlet.java

package servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import po.User;
import dao.UserDAO;

public class GetUserServlet extends HttpServlet {

    /**
     * Constructor of the object.
     */
    public GetUserServlet() {
        super();
    }

    /**
     * Destruction of the servlet. <br>
     */
    public void destroy() {
        super.destroy(); // Just puts "destroy" string in log
        // Put your code here
    }

    /**
     * The doGet method of the servlet. <br>
     *
     * This method is called when a form has its tag value method equals to get.
     * 
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doPost(request,response);
    }

    /**
     * The doPost method of the servlet. <br>
     *
     * This method is called when a form has its tag value method equals to post.
     * 
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        out
                .println("<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">");
        out.println("<HTML>");
        out.println("  <HEAD><TITLE>A Servlet</TITLE></HEAD>");
        out.println("  <BODY>");
    
//根据id 查找到所有字段返回给exit.jsp

        HttpSession  session=request.getSession(true);
         String sid=request.getParameter("userid");
         int id=Integer.parseInt(sid);
         UserDAO udao=new UserDAO();
            User u= udao.getUser(id);
                 //传递给session 对象
             session.setAttribute("user", u);
            response.sendRedirect("../edit.jsp");
        
        out.println("  </BODY>");
        out.println("</HTML>");
        out.flush();
        out.close();
    }

    /**
     * Initialization of the servlet. <br>
     *
     * @throws ServletException if an error occurs
     */
    public void init() throws ServletException {
        // Put your code here
    }

}
                       

edit.jsp 修改好后的传递给

EditServlet.java

package servlet;

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 po.User;
import dao.UserDAO;

public class EditServlet extends HttpServlet {

    /**
     * Constructor of the object.
     */
    public EditServlet() {
        super();
    }

    /**
     * Destruction of the servlet. <br>
     */
    public void destroy() {
        super.destroy(); // Just puts "destroy" string in log
        // Put your code here
    }

    /**
     * The doGet method of the servlet. <br>
     *
     * This method is called when a form has its tag value method equals to get.
     * 
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        doPost(request,response);
    }

    /**
     * The doPost method of the servlet. <br>
     *
     * This method is called when a form has its tag value method equals to post.
     * 
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        out
                .println("<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">");
        out.println("<HTML>");
        out.println("  <HEAD><TITLE>A Servlet</TITLE></HEAD>");
        out.println("  <BODY>");
        //获取edit 传递的字段

           String userid=request.getParameter("userid");
           String username=request.getParameter("username");
            String userpwd=request.getParameter("userpwd");
            String sex=request.getParameter("sex");
            String age=request.getParameter("age");
            String address=request.getParameter("address");   

          User u=new User();
              u.setId(Integer.parseInt(userid));
              u.setUsername(username);
              u.setPassword(userpwd);
              u.setSex(sex);
              u.setAge(Integer.parseInt(age));
              u.setAddress(address);
              
          //调用方法
            UserDAO udao=new UserDAO();
               
              int n=udao.edit(u);
                if(n>0) {
//成功就调用查询方法  看修改完后的
                    response.sendRedirect("../servlet/GetUsersServlet");
                }
                else
                {
                 out.println("修改失败");
                }
        
        
        
        out.println("  </BODY>");
        out.println("</HTML>");
        out.flush();
        out.close();
    }

    /**
     * Initialization of the servlet. <br>
     *
     * @throws ServletException if an error occurs
     */
    public void init() throws ServletException {
        // Put your code here
    }

}

login.jsp 调用

package servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.*;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import dao.UserDAO;
import db.DbConn;

public class LoginServlet extends HttpServlet {

    /**
     * Constructor of the object.
     */
    public LoginServlet() {
        super();
    }

    /**
     * Destruction of the servlet. <br>
     */
    public void destroy() {
        super.destroy(); // Just puts "destroy" string in log
        // Put your code here
    }

    /**
     * The doGet method of the servlet. <br>
     *
     * This method is called when a form has its tag value method equals to get.
     * 
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
          doPost(request,response);
    }

    /**
     * The doPost method of the servlet. <br>
     *
     * This method is called when a form has its tag value method equals to post.
     * 
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        out
                .println("<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">");
        out.println("<HTML>");
        out.println("  <HEAD><TITLE>A Servlet</TITLE></HEAD>");
        out.println("  <BODY>");
        
        String username=(String)request.getParameter("username");
        String userpwd=(String)request.getParameter("password");
  
              UserDAO udao=new UserDAO();
           boolean flag= udao.login(username, userpwd);
    
        if(flag==true){
            out.print("success");
        
            response.sendRedirect("../servlet/GetUsersServlet");
            
        }
        else
            out.print("false");
        
        
        out.println("  </BODY>");
        out.println("</HTML>");
        out.flush();
        out.close();
    }

    /**
     * Initialization of the servlet. <br>
     *
     * @throws ServletException if an error occurs
     */
    public void init() throws ServletException {
        // Put your code here
    }

}

查询所有GetUsersServlet.java

package servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import po.User;

import dao.UserDAO;

public class GetUsersServlet extends HttpServlet {

    /**
     * Constructor of the object.
     */
    public GetUsersServlet() {
        super();
    }

    /**
     * Destruction of the servlet. <br>
     */
    public void destroy() {
        super.destroy(); // Just puts "destroy" string in log
        // Put your code here
    }

    /**
     * The doGet method of the servlet. <br>
     *
     * This method is called when a form has its tag value method equals to get.
     * 
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doPost(request,response);
    }

    /**
     * The doPost method of the servlet. <br>
     *
     * This method is called when a form has its tag value method equals to post.
     * 
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        out
                .println("<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">");
        out.println("<HTML>");
        out.println("  <HEAD><TITLE>A Servlet</TITLE></HEAD>");
        out.println("  <BODY>");
          HttpSession  session=request.getSession(true);
         
         UserDAO udao=new UserDAO();
          List<User> ls= udao.getUserList();
             session.setAttribute("userlist", ls);
            response.sendRedirect("../main.jsp");
            
        out.println("  </BODY>");
        out.println("</HTML>");
        out.flush();
        out.close();
    }

    /**
     * Initialization of the servlet. <br>
     *
     * @throws ServletException if an error occurs
     */
    public void init() throws ServletException {
        // Put your code here
    }

}

DelServlet.java

package servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.*;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import db.DbConn;

public class DelServlet extends HttpServlet {

    /**
     * Constructor of the object.
     */
    public DelServlet() {
        super();
    }

    /**
     * Destruction of the servlet. <br>
     */
    public void destroy() {
        super.destroy(); // Just puts "destroy" string in log
        // Put your code here
    }

    /**
     * The doGet method of the servlet. <br>
     *
     * This method is called when a form has its tag value method equals to get.
     * 
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */
    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doPost(request,response);
    }

    /**
     * The doPost method of the servlet. <br>
     *
     * This method is called when a form has its tag value method equals to post.
     * 
     * @param request the request send by the client to the server
     * @param response the response send by the server to the client
     * @throws ServletException if an error occurred
     * @throws IOException if an error occurred
     */
    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        out
                .println("<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">");
        out.println("<HTML>");
        out.println("  <HEAD><TITLE>A Servlet</TITLE></HEAD>");
        out.println("  <BODY>");
    
         String userid=request.getParameter("userid");
            out.println(userid);


            try {
                // 创建连接 testdb是数据库名称
                Connection con = DbConn.getConn();                
                // 创建声明SQL对象
                Statement stm = con.createStatement();
                // 执行SQL语句，得到结果集，结果集放到ResultSet对象中
                
                int n=stm.executeUpdate(sql);
                if(n>0) {
                    response.sendRedirect("../servlet/GetUsersServlet");    
                    
                }
                else
                {
                 out.println("删除失败");
                }

            } catch (SQLException e) {

                System.out.println("数据库操作出错" + e.getMessage());
            }

        
        
        
        out.println("  </BODY>");
        out.println("</HTML>");
        out.flush();
        out.close();
    }

    /**
     * Initialization of the servlet. <br>
     *
     * @throws ServletException if an error occurs
     */
    public void init() throws ServletException {
        // Put your code here
    }

}

1.main.jsp 

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ page import="po.*" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <title>My JSP 'main.jsp' starting page</title>
  </head>
  
  <body>
 <table width="502" border="1">
  <tr>
    <td width="37">序号</td>
    <td width="63">姓名</td>
    <td width="52">密码</td>
    <td width="52">年龄</td>
    <td width="61">性别</td>
    <td width="197">地址</td>
    <td width="80">删除</td>
    <td width="80">修改</td>
  </tr>
  <%
  
        List<User> ls=(List<User>)session.getAttribute("userlist");
        for(int i=0;i<ls.size();i++)
        {
            User u=ls.get(i);
            %>
         <tr>
            <td><%=u.getId()%></td>
            <td><%=u.getUsername()%></td>
            <td><%=u.getPassword()%></td>
            <td><%=u.getAge()%></td>
            <td><%=u.getSex()%></td>
            <td><%=u.getAddress()%></td>
            <td><a href="servlet/DelServlet?userid=<%=u.getId()%>">删除</a></td>
               <td><a href="servlet/GetUserServlet?userid=<%=u.getId()%>">修改</a></td>
        </tr>
       <% 
     }
   %>
   </table>
   <a href="add.jsp">添加</a>
  </body>
</html>

2.修改  edit.jsp

<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
 <%@ page import="po.*" %>
<!DOCTYPE html PUBLIC "-//W3C//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=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>


<% 
  User u=(User)session.getAttribute("user");
%>
<p>用户添加</p>
<form  name="frm1" action="servlet/EditServlet">
<p>姓名：
  <label for="textfield"></label>
  <input type="text" name="username" id="textfield" value="<%=u.getUsername() %>"/>
  <input type="hidden" name="userid" id="textfield" value="<%=u.getId() %>"/>
</p>
<p>密码：
  <input type="text" name="userpwd" id="textfield2"   value="<%= u.getPassword()%>"/>
</p>
<p>年龄：
  <input type="text" name="age" id="textfield3"   value="<%=u.getAge() %>"/>
</p>
<p>性别：
  <input type="text" name="sex" id="textfield4"  value="<%=u.getSex() %>"/>
</p>
<p>地址：
  <input type="text" name="address" id="textfield5"   value="<%=u.getAddress() %>"/>
</p>
<p>&nbsp;</p>
<input type="submit" value="确定"/>
</form>
</body>
</html>

3.Login

<%@ page language="java" import="java.util.*" pageEncoding="GB2312"%>
<%
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>
    <div align="center" >
       <form method="get" action="servlet/LoginServlet">
               用户名:<input type="text" name="username"><br>
            密码：<input type="password" name="password"><br>
            <input type="submit" name="button1" value="登录">
        </form>
    </div>
</body>
</html>

运行过程

修改的运行过程： Login.jsp--->LoginServlet-->main.jsp-->GetUserServlet->exit.jsp->EditServlet ->main.jsp