话不多说，请看代码

package ceet.ac.cn.dao;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import java.util.ArrayList;import java.util.List;import ceet.ac.cn.model.Admin;public class AdminDao { public List<Admin> getAllAdmin(){ //查询所有信息 List<Admin> list = new ArrayList<Admin>(); //创建集合 Connection conn = DbHelper.getConnection(); String sql = "select * from admin"; //SQL查询语句 try { PreparedStatement pst = conn.prepareStatement(sql); ResultSet rst = pst.executeQuery(); while (rst.next()) { Admin admin = new Admin(); admin.setId(rst.getInt("id")); //得到ID admin.setUsername(rst.getString("username")); admin.setUserpwd(rst.getString("userpwd")); list.add(admin); } rst.close(); //关闭 pst.close(); //关闭 } catch (SQLException e) { e.printStackTrace(); //抛出异常 } return list; //返回一个集合 } public boolean addAdmin(Admin admin){ //添加信息 String sql = "INSERT INTO `admin`(`id`,`username`,`userpwd`) VALUES (?,?,?)"; //添加的SQL语句 Connection conn = DbHelper.getConnection(); try { PreparedStatement pst = conn.prepareStatement(sql); pst.setInt(1, admin.getId()); pst.setString(2, admin.getUsername()); pst.setString(3, admin.getUserpwd()); int count = pst.executeUpdate(); pst.close(); return count>0?true:false; //是否添加的判断 } catch (SQLException e) { e.printStackTrace(); } return false; } public boolean updateAdmin(Admin admin){ //修改 String sql = "UPDATE `admin` SET `username`=?,`userpwd`=? WHERE `id` = ?"; //修改的SQL语句，根据ID修改 Connection conn = DbHelper.getConnection(); try { PreparedStatement pst = conn.prepareStatement(sql); pst.setString(1, admin.getUsername()); pst.setString(2, admin.getUserpwd()); pst.setInt(3, admin.getId()); //根据的ID int count = pst.executeUpdate(); pst.close(); //关闭 return count>0?true:false; //是否修改的判断 } catch (SQLException e) { e.printStackTrace(); } return false; } public boolean deleteAdmin(int id){ //删除 String sql = "delete from admin where id = ?"; //删除的SQL语句，根据ID删除 Connection conn = DbHelper.getConnection(); try { PreparedStatement pst = conn.prepareStatement(sql); pst.setInt(1, id); int count = pst.executeUpdate(); pst.close(); return count>0?true:false; //是否删除的判断 } catch (SQLException e) { e.printStackTrace(); } return false; } public Admin selectAdminById(int id){ //根据ID进行查询 Connection conn = DbHelper.getConnection(); String sql = "select * from admin where id = "+id; Admin admin = null; try { PreparedStatement pst = conn.prepareStatement(sql); ResultSet rst = pst.executeQuery(); while (rst.next()) { admin = new Admin(); admin.setId(rst.getInt("id")); admin.setUsername(rst.getString("username")); admin.setUserpwd(rst.getString("userpwd")); } rst.close(); pst.close(); } catch (SQLException e) { e.printStackTrace(); } return admin; //返回 }}package ceet.ac.cn.dao;import java.sql.Connection;import java.sql.DriverManager;/** * 连接数据库 * @author 画船听雨眠 * */public class DbHelper { private static String url = "jdbc:mysql://localhost:3306/admin"; //数据库地址 private static String userName = "root"; //数据库用户名 private static String passWord = "359129127"; //数据库密码 private static Connection conn = null; private DbHelper(){ } public static Connection getConnection(){ if(null == conn){ try { Class.forName("com.mysql.jdbc.Driver"); conn = DriverManager.getConnection(url, userName, passWord); } catch (Exception e) { e.printStackTrace(); } } return conn; } public static void main(String[] args) { //测试数据库是否连通 System.err.println(getConnection()); }}package ceet.ac.cn.model;import java.io.Serializable;public class Admin implements Serializable{ //数据封装类 private static final long serialVersionUID = 1L; private int id; private String username; private String userpwd; 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 getUserpwd() { return userpwd; } public void setUserpwd(String userpwd) { this.userpwd = userpwd; }}package ceet.ac.cn.servlet;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import ceet.ac.cn.dao.AdminDao;import ceet.ac.cn.model.Admin;public class AddServlet extends HttpServlet{ //添加数据 private static final long serialVersionUID = 1L; protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { this.doPost(req, resp); } protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String username = req.getParameter("username"); String userpwd = req.getParameter("userpwd"); Admin admin = new Admin(); admin.setUsername(new String(username.getBytes("ISO-8859-1"),"UTF-8")); //转值，中文需要转换为utf-8 admin.setUserpwd(new String(userpwd.getBytes("ISO-8859-1"),"UTF-8")); AdminDao dao = new AdminDao(); dao.addAdmin(admin); req.getRequestDispatcher("ShowServlet").forward(req, resp); } }package ceet.ac.cn.servlet;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import ceet.ac.cn.dao.AdminDao;public class DeleteServlet extends HttpServlet{ //删除数据 private static final long serialVersionUID = 1L; protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { this.doPost(req, resp); } protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String idStr = req.getParameter("id"); //删除数据的ID，根据ID删除 if(idStr != null && !idStr.equals("")){ int id = Integer.valueOf(idStr); AdminDao dao = new AdminDao(); dao.deleteAdmin(id); } req.getRequestDispatcher("ShowServlet").forward(req, resp); }}package ceet.ac.cn.servlet;import java.io.IOException;import java.util.List;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import ceet.ac.cn.dao.AdminDao;import ceet.ac.cn.model.Admin;public class ShowServlet extends HttpServlet{ //显示全部数据 private static final long serialVersionUID = 1L; protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { this.doPost(req, resp); } protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { AdminDao dao = new AdminDao(); List<Admin> list = dao.getAllAdmin(); req.setAttribute("list", list); req.getRequestDispatcher("index.jsp").forward(req, resp); } }package ceet.ac.cn.servlet;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import ceet.ac.cn.dao.AdminDao;import ceet.ac.cn.model.Admin;public class UpdateServlet extends HttpServlet{ //修改 private static final long serialVersionUID = 1L; protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { //查询到选中ID的值所对应的数据 String idStr = req.getParameter("id"); if(idStr != null && !idStr.equals("")){ int id = Integer.valueOf(idStr); AdminDao dao = new AdminDao(); Admin admin = dao.selectAdminById(id); req.setAttribute("admin", admin); } req.getRequestDispatcher("update.jsp").forward(req, resp); } protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { //根据此ID对数据的值进行修改 String username = req.getParameter("username"); String userpwd = req.getParameter("userpwd"); String idStr = req.getParameter("id"); Admin admin = new Admin(); admin.setId(Integer.valueOf(idStr)); admin.setUsername(new String(username.getBytes("ISO-8859-1"),"UTF-8")); admin.setUserpwd(new String(userpwd.getBytes("ISO-8859-1"),"UTF-8")); AdminDao dao = new AdminDao(); dao.updateAdmin(admin); req.getRequestDispatcher("ShowServlet").forward(req, resp); }}<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html> <head> <title>添加</title> <link rel="stylesheet" href="css/index.css" type="text/css" /> </head> <body> <form action="AddServlet" method="post"> <table border="1" class="t1"> <tr> <td colspan="2"><h1>添加管理员</h1></td> </tr> <tr> <td>管理员帐号:</td> <td><input type="text" name="username"/></td> </tr> <tr> <td>管理员密码:</td> <td><input type="password" name="userpwd"/></td> </tr> <tr> <td colspan="2"> <input type="submit" value="提交"/> <input type="reset" value="清空"/> </td> </tr> </table> </form> </body></html><%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%><%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %><!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=utf-8"><title>显示</title> <style type="text/css"> table { border: 1px solid pink; margin: 0 auto; } td{ width: 150px; border: 1px solid pink; text-align: center; } </style></head><body> <table> <tr> <td>编号</td> <td>帐号</td> <td>密码</td> <td>操作</td> </tr> <c:forEach items="${list}" var="item"> <tr> <td>${item.id }</td> <td>${item.username }</td> <td>${item.userpwd }</td> <td><a href="DeleteServlet?id=${item.id }">删除</a>|<a href="UpdateServlet?id=${item.id }">修改</a></td> </tr> </c:forEach> <tr> <td colspan="6" style="text-align: left;"><a href="add.jsp">添加管理员</a></td> </tr> </table></body></html><%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html> <head> <title>修改</title> <link rel="stylesheet" href="css/index.css" type="text/css" /> </head> <body> <form action="UpdateServlet" method="post"> <table border="1" class="t1"> <tr> <td colspan="2"><h1>修改管理员信息</h1></td> </tr> <tr> <td>编号:</td> <td><input type="text" name="id" value="${admin.id}" readonly="readonly"/></td> </tr> <tr> <td>管理员帐号:</td> <td><input type="text" name="username" value="${admin.username}"/></td> </tr> <tr> <td>管理员密码:</td> <td><input type="text" name="userpwd" value="${admin.userpwd}"/></td> </tr> <tr> <td colspan="2"> <input type="submit" value="提交"/> <input type="button" value="返回" onclick="history.go(-1)"/> </td> </tr> </table> </form> </body></html>@CHARSET "UTF-8"; table.t1 { margin-top:10px; margin-left:20px; margin-right:20px; margin-bottom:5px; #background-color: #FFF; #background:#EEF4F9; #border: none; border: 1; #color:#003755; border-collapse:collapse; font: 14px "宋体"; text-align: center; } table.t1 th{ background:#7CB8E2; color:#fff; padding:6px 4px; text-align:center; } table.t1 td{ background:#C7DDEE none repeat-x scroll center left; color:#000; padding:4px 2px; } table.t1 a{ text-decoration:none; height:1em; } table.t1 a:link, table.t1 a:visited{ color:#3366CC; } table.t1 a:hover{ color:#B50000; text-decoration:underline; }

最简单的jsp+servlet的增删改查代码。写的很清楚，就这样了。

实现原理：

每行数据后面加一个编辑和删除按钮，按钮提交到后台并且带有此行数据的主要参数。

点击编辑按钮，通过servlet操作jsp将此行的每一列替换为一个文本框并把已有的值带进去，后面一个提交按钮通过submit提交数据并将文本框重新变为表格的单元格。

新增，就像编辑一样，添加一行，全部是文本框。。。

以上就是本文的全部内容，希望本文的内容对大家的学习或者工作能带来一定的帮助，同时也希望多多支持！