jsp+servlet实现最简单的增删改查代码分享

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！