JSP + Servlet + JDBC + Mysql 简单实现增删改查
源码下载：https://download.csdn.net/download/johnfht/12201202
一，准备
1，工具
IDE：IntelliJ IDEA
数据库：mysql
数据库操作工具：Navicat for MySQL
2，数据表
3，项目结构
二，后端代码
1，数据库工具 DBUtil.java
package com.util;
import java.sql.*;
/**
* 数据库工具
*/
public class DBUtil {
private static String dbUrl = "jdbc:mysql://localhost:3306/javawebdemo"; //数据库地址
private static String dbUser = "root"; //数据库用户
private static String dbPwd = "123456"; //数据库密码
private static String dbDriver = "com.mysql.jdbc.Driver"; //数据库驱动
private static Connection conn = null;
//获取连接
public static Connection getConn(){
if(null == conn){
try {
Class.forName(dbDriver);
conn = DriverManager.getConnection(dbUrl, dbUser, dbPwd);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
}
return conn;
}
/*//测试
@Test
public void test(){
if(getConn() != null){
System.out.println("数据库连接成功");
}else{
System.out.println("数据库连接失败");
}
}*/
}2，实体类 User.java
package com.domain;
/**
* 用户实体类
*/
public class User {
private int id;
private String username;
private String password;
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;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", username='" + username + '\'' +
", password='" + password + '\'' +
'}';
}
}3，数据库交互 dao层 UserDao.java
package com.dao;
import com.domain.User;
import com.util.DBUtil;
import org.junit.Test;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
/**
* 数据库交互 dao层
*/
public class UserDao {
public List getAllUser(){
List list = new ArrayList<>();
Connection conn = DBUtil.getConn();
String sql = "select * from user";
try {
PreparedStatement pst = conn.prepareStatement(sql);
ResultSet rs = pst.executeQuery();
while(rs.next()){
User user = new User();
user.setId(rs.getInt("id"));
user.setUsername(rs.getString("username"));
user.setPassword(rs.getString("password"));
list.add(user);
}
rs.close();
pst.close();
} catch (SQLException e) {
e.printStackTrace();
}
return list;
}
public boolean addUser(User user){
String sql = "insert into user(username, password) values(?,?)";
Connection conn = DBUtil.getConn();
try {
PreparedStatement pst = conn.prepareStatement(sql);
pst.setString(1, user.getUsername());
pst.setString(2, user.getPassword());
int count = pst.executeUpdate();
pst.close();
return count>0 ? true:false;
} catch (SQLException e) {
e.printStackTrace();
}
return false;
}
public boolean deleteUser(int id){
String sql = "delete from user where id = ?";
Connection conn = DBUtil.getConn();
try {
PreparedStatement pst = conn.prepareStatement(sql);
pst.setInt(1, id);
int count = 0;
count = pst.executeUpdate();
pst.close();
return count>0 ? true:false;
} catch (SQLException e) {
e.printStackTrace();
}
return false;
}
public boolean updateUser(User user){
String sql = "update user set username=?,password=? where id=?";
Connection conn = DBUtil.getConn();
try {
PreparedStatement pst = conn.prepareStatement(sql);
pst.setString(1,user.getUsername());
pst.setString(2, user.getPassword());
pst.setInt(3, user.getId());
int count = pst.executeUpdate();
pst.close();
return count>0 ? true:false;
} catch (SQLException e) {
e.printStackTrace();
}
return false;
}
public User findUserById(int id){
String sql = "select * from user where id = " + id;
Connection conn = DBUtil.getConn();
User user = null;
try {
PreparedStatement pst = conn.prepareStatement(sql);
ResultSet rs = pst.executeQuery();
while (rs.next()){
user = new User();
user.setId(rs.getInt("id"));
user.setUsername(rs.getString("username"));
user.setPassword(rs.getString("password"));
}
rs.close();
pst.close();
} catch (SQLException e) {
e.printStackTrace();
}
return user;
}
@Test
public void test(){
User user = new User();
user.setUsername("admin1");
user.setPassword("123456");
UserDao ud = new UserDao();
boolean b = ud.addUser(user);
if(b){
System.out.println("添加数据成功");
}
}
} 4，web控制添加数据 AddServlet.java
package com.servlet;
import com.dao.UserDao;
import com.domain.User;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@WebServlet("/addServlet")
public class AddServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setContentType("utf-8");
String username = request.getParameter("username");
String password = request.getParameter("password");
User u = new User();
u.setUsername(username);
u.setPassword(password);
/*u.setUsername(new String(username.getBytes("ISO-8859-1"),"UTF-8"));
u.setPassword(new String(password.getBytes("ISO-8859-1"),"UTF-8"));*/
UserDao ud = new UserDao();
ud.addUser(u);
request.getRequestDispatcher("showServlet").forward(request,response);
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request,response);
}
}5，web控制删除数据 DeleteServlet.java
package com.servlet;
import com.dao.UserDao;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@WebServlet("/deleteServlet")
public class DeleteServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setContentType("utf-8");
String idStr = request.getParameter("id");
int id = Integer.valueOf(idStr);
UserDao ud = new UserDao();
if(ud.deleteUser(id)){
request.setAttribute("deleted", "删除成功！");
request.getRequestDispatcher("showServlet").forward(request,response);
}else{
response.sendRedirect("showServlet");
}
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request,response);
}
}6，web控制修改数据 UpdateServlet.java
package com.servlet;
import com.dao.UserDao;
import com.domain.User;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@WebServlet("/updateServlet")
public class UpdateServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setContentType("utf-8");
String idStr = request.getParameter("id");
if (idStr != null && !idStr.equals("")) {
int id = Integer.valueOf(idStr);
UserDao dao = new UserDao();
User user = dao.findUserById(id);
request.setAttribute("user", user);
}
request.getRequestDispatcher("update.jsp").forward(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String username = request.getParameter("username");
String password = request.getParameter("password");
String idStr = request.getParameter("id");
User u = new User();
u.setId(Integer.valueOf(idStr));
u.setUsername(username);
u.setPassword(password);
UserDao ud = new UserDao();
ud.updateUser(u);
request.getRequestDispatcher("showServlet").forward(request, response);
}
}6，web控制显示数据 ShowServlet.java
package com.servlet;
import com.dao.UserDao;
import com.domain.User;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;
@WebServlet("/showServlet")
public class ShowServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setContentType("utf-8");
UserDao ud = new UserDao();
List list = ud.getAllUser();
request.setAttribute("list", list);
request.getRequestDispatcher("index.jsp").forward(request,response);
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request,response);
}
} 三，jsp前端页面
1，添加数据 add.jsp
<%--
Created by IntelliJ IDEA.
User: Administrator
Date: 2/28/2020
Time: 9:13 PM
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
用户添加
2，显示数据 index.jsp
<%--
Created by IntelliJ IDEA.
User: Administrator
Date: 2/28/2020
Time: 9:13 PM
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
用户展示
用户展示
${deleted}
编号
用户名
密码
操作
${item.id}
${item.username}
${item.password}
删除-----编辑
用户添加
3，修改数据 update.jsp
<%--
Created by IntelliJ IDEA.
User: Administrator
Date: 2/28/2020
Time: 9:14 PM
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
用户编辑
四，页面效果
