JavaWeb案例(MVC+MySQL+分页功能)+前后端分离

具备的测试工具：Eclipse，MySQL数据库，HBuilder，jstl1.2jar，mysql.connector.java.8.0.jar

jstl1.2jar下载地址：https://pan.baidu.com/s/1T23zxoEg3jlZHFikrbWtHw

mysql.connector.java.8.0.jar包下载地址：https://pan.baidu.com/s/1kqfOuxo3nOT--CTrlp1BmA

首先打开Eclipse创建一个动态Web项目(Dynamic Web Project)，在Src下分别创建以下包

其中web其实就是对应action层，这就是典型的MVC模型，这是属于后端

首先创建与你数据库的表结构对应的实体类

1、我的数据库结构如下

建立数据库
create database LoveDB;

建立数据表LoveInHeart
use LoveDB;
create table LoveInHeart(
lid int auto_increment primary key,
lname varchar(50) not null,
lsex varchar(50) not null,
ltime date not null,
lmoney float
);

然后可以向里面添加一些测试数据

insert into LoveInHeart(lname,lsex,ltime,lmoney)
values ('廖远平','男','1999-02-15',1000000);

insert into LoveInHeart(lname,lsex,ltime,lmoney)
values ('彭桂妮','女','1998-8-19',1000);

insert into LoveInHeart(lname,lsex,ltime,lmoney)
values ('科比','男','2008-05-05',100);

然后实体类的属性参数要和数据库的表结构保持一致，注：实体类是放在entity包下

声明变量以后进行封装，右键选择 source --> Getter and Setter ，然后select All 点击完成

接下来创建与数据库链接的DatabaseConnection类来完成与数据库的交互，在dao包下新建一个类，名字为：BaseDB

package com.nf.dao;import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;public class BaseDao {private static final String DRIVER_CLASS = "com.mysql.cj.jdbc.Driver";private static final String SERVER_IP = "localhost";// 服务器IP地址private static final String DATABASE_NAME = "lovedb";// 连接到哪一个数据库private static final String USER_NAME = "root";// 用户名private static final String PASSWORD = "123456";// 密码public Connection getConnection() {Connection conn = null;String jdbcUrl = "jdbc:mysql://" + SERVER_IP + ":3306/" + DATABASE_NAME+ "?serverTimezone=Asia/Shanghai&useSSL=true";try {Class.forName(DRIVER_CLASS);conn = DriverManager.getConnection(jdbcUrl, USER_NAME, PASSWORD);} catch (Exception e) {System.out.println("获取连接时，异常" + e.getMessage());conn = null;}return conn;}public void closeAll(Connection conn, PreparedStatement pst, ResultSet rs) {try {if (rs != null) {rs.close();}if (pst != null) {pst.close();}if (conn != null) {conn.close();}} catch (SQLException e) {// TODO Auto-generated catch block
            e.printStackTrace();}}}

在dao层下面创建一个Interface类，声明三个方法(查询、添加、删除)，名字：LoveInHeartDao

package com.nf.dao;import java.util.List;
import com.nf.entity.LoveInHeart;
import com.nf.util.MyPage;public interface LoveInHeartDao{public List<LoveInHeart> getAll(MyPage myPage);public boolean add(LoveInHeart love);public boolean delete(int id);}

然后创建一个实现接口class类(Implments)，名字：LoveInHeart_Impl

package com.nf.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 com.nf.entity.LoveInHeart;
import com.nf.util.MyPage;public class LoveInHeartDaoImpl extends BaseDao implements LoveInHeartDao {@Override  //查询public List<LoveInHeart> getAll(MyPage myPage) {// 操作数据库，需要一个连接ConnectionConnection connection = getConnection();PreparedStatement prepareStatement = null;ResultSet resultSet = null;List<LoveInHeart> loveInHeartList = new ArrayList();String sql_data = "select * from loveinheart order by lid desc ";String sql_recodeCount = "select count(1) as mycount from loveinheart";sql_data += "limit ";sql_data += (myPage.getCurrentPage()-1)*myPage.getPerPageSize();sql_data += ",";sql_data += myPage.getPerPageSize();System.out.println("分页的SQL:"+sql_data);try {prepareStatement = connection.prepareStatement(sql_data);resultSet = prepareStatement.executeQuery();while (resultSet.next()) {LoveInHeart l = new LoveInHeart();l.setLid(resultSet.getInt("lid"));l.setLname(resultSet.getString("lname"));l.setLsex(resultSet.getString("lsex"));l.setLtime(resultSet.getDate("ltime"));l.setLmoney(resultSet.getFloat("lmoney"));loveInHeartList.add(l);}} catch (SQLException e) {e.printStackTrace();}try {prepareStatement = connection.prepareStatement(sql_recodeCount);resultSet = prepareStatement.executeQuery();resultSet.next();myPage.setRecodeCount( resultSet.getInt("mycount") );} catch (SQLException e) {e.printStackTrace();}closeAll(connection, prepareStatement, resultSet);// System.out.println(connection);return loveInHeartList;}@Override   //添加public boolean add(LoveInHeart love) {// 操作数据库，需要一个连接ConnectionConnection connection = getConnection();PreparedStatement prepareStatement = null;try {prepareStatement = connection.prepareStatement("insert into LoveInHeart(lname,lsex,ltime,lmoney) values (?,?,?,?)");prepareStatement.setString(1, love.getLname());prepareStatement.setString(2, love.getLsex());prepareStatement.setDate(3, love.getLtime());prepareStatement.setFloat(4, love.getLmoney());prepareStatement.executeUpdate();closeAll(connection, prepareStatement, null);return true;} catch (SQLException e) {e.printStackTrace();return false;}}@Override    //删除public boolean delete(int id) {// 操作数据库，需要一个连接ConnectionConnection connection = getConnection();PreparedStatement prepareStatement = null;try {prepareStatement = connection.prepareStatement("delete from LoveInHeart where lid=?");prepareStatement.setInt(1, id);prepareStatement.executeUpdate();closeAll(connection, prepareStatement, null);return true;} catch (SQLException e) {e.printStackTrace();return false;}}}

接下来在Service层再创建一个interface类，名字：LoveInHeartService

package com.nf.service;import java.util.List;
import com.nf.entity.LoveInHeart;
import com.nf.entity.MyData;public interface LoveInHeartService {public MyData getAll(int currentPage);public boolean add(LoveInHeart love);public boolean delete(int id);
}

随机在同Service层下实现该接口，实现类名：LoveInHeartServiceImpl，在这里实现类的方式直接调用dao层的方法就可以了

package com.nf.service;import java.util.List;import com.nf.dao.LoveInHeartDao;
import com.nf.dao.LoveInHeartDaoImpl;
import com.nf.entity.LoveInHeart;
import com.nf.entity.MyData;
import com.nf.util.MyPage;public class LoveInHeartServiceImpl implements LoveInHeartService {private LoveInHeartDao loveDao = new LoveInHeartDaoImpl();@Overridepublic MyData getAll(int currentPage) {MyPage myPage = new MyPage();myPage.setCurrentPage(currentPage);//myPage.setRecodeCount( 0  );//让Dao层来计算myPage.setPerPageSize( 10 );//设置每页10条
        List<LoveInHeart> loveList = loveDao.getAll( myPage  );MyData myData = new MyData();myData.setLoveInHeartList(loveList);myData.setMyPage(myPage);return myData;}@Overridepublic boolean add(LoveInHeart love) {return loveDao.add(love);}@Overridepublic boolean delete(int id) {// TODO Auto-generated method stubreturn loveDao.delete(id);}}

接下来就是存放Servlet的action层，Servlet名：LoveInHeartActionGetAll(获取全部信息的Servlet)

package com.nf.web;import java.io.IOException;
import java.util.List;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 com.nf.entity.LoveInHeart;
import com.nf.entity.MyData;
import com.nf.service.LoveInHeartService;
import com.nf.service.LoveInHeartServiceImpl;@WebServlet("/LoveInHeartActionGetAll")
public class LoveInHeartActionGetAll extends HttpServlet {protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//第一步：先获得客户端的参数String currentPage_str = request.getParameter("currentPage");if (currentPage_str==null){currentPage_str = "1";}int currentPage = Integer.parseInt(currentPage_str);//第二步：调用Model（service层）的方法，来获取数据LoveInHeartService loveService = new LoveInHeartServiceImpl();MyData myData = loveService.getAll(currentPage);//第三步：把数据存放到request的属性中，然后把请求转发到jsprequest.setAttribute("myData", myData);request.getRequestDispatcher("showList.jsp").forward(request, response);}protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doGet(request, response);}}

再在同一层下创建添加的Servlet，Servlet名：LoveInHeartActionAdd

package com.nf.web;import java.io.IOException;
import java.text.ParseException;
import java.text.SimpleDateFormat;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 com.nf.entity.LoveInHeart;
import com.nf.service.LoveInHeartService;
import com.nf.service.LoveInHeartServiceImpl;@WebServlet("/LoveInHeartActionAdd")
public class LoveInHeartActionAdd extends HttpServlet {protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//获取参数//?lname=123&lsex=男&ltime=111&lmoney=222String lname = request.getParameter("lname");String lsex = request.getParameter("lsex");String ltime = request.getParameter("ltime");String lmoney = request.getParameter("lmoney");//把参数构造成一个实体类LoveInHeart love = new LoveInHeart();love.setLname(lname);love.setLsex(lsex);SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");try {love.setLtime( new java.sql.Date( sdf.parse(ltime).getTime() ) );} catch (ParseException e) {System.out.println("日期格式转换错误");e.printStackTrace();}love.setLmoney( Float.parseFloat(lmoney) );//调用Model，保存数据LoveInHeartService loveService = new LoveInHeartServiceImpl();boolean flag = loveService.add(love);//跳转if (flag){//response.sendRedirect("showList.jsp");response.sendRedirect("LoveInHeartActionGetAll");}else{response.sendRedirect("error.jsp");}}protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doGet(request, response);}}

删除的Servlet，Servlet名：LoveInHeartActionDelete

package com.nf.web;import java.io.IOException;
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 com.nf.service.LoveInHeartService;
import com.nf.service.LoveInHeartServiceImpl;@WebServlet("/LoveInHeartActionDelete")
public class LoveInHeartActionDelete extends HttpServlet {protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//获取参数String id_str = request.getParameter("id");int id = Integer.parseInt(id_str);//调用model的apiLoveInHeartService loveService = new LoveInHeartServiceImpl();boolean flag = loveService.delete(id);if (flag){response.sendRedirect("LoveInHeartActionGetAll");}else{response.sendRedirect("error.jsp");}}protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doGet(request, response);}}

添加JSP代码，此网页只有主体，无其它程序文件之类的引用，JSP名：add.jsp

<form action="LoveInHeartActionAdd">
<table border="1" width="80%" align="center"><tr><td colspan="2" align="center">中华慈善捐款等级</td></tr><tr><td width="180px">姓名：</td><td><input type="text" name="lname"></td></tr><tr><td width="180px">性别：</td><td><input type="radio" name="lsex" value="男" checked="checked">男</input><input type="radio" name="lsex" value="女">女</input></td></tr><tr><td width="180px">捐款日期：</td><td><input type="text" name="ltime">(yyyy年MM月dd日)</td></tr><tr><td width="180px">捐款金额：</td><td><input type="text" name="lmoney">(元)</td></tr><tr><td colspan="2" align="center"><input type="submit" value="提交"><input type="reset" value="重置"></td></tr>
</table>
</form>

首页的全部代码，这里只是用来做一个中转站，并不实现什么功能，所以可以只保留这一点东西，JSP名：index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%><%response.sendRedirect("LoveInHeartActionGetAll");%>

最重要的展示信息界面，包括了删除功能，JSP名：showList.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!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>展示所有信息</title>
</head>
<script type="text/javascript">
function mydelete(id){alert(id);//ajax();
}</script>
<body>总纪录条数：${myData.myPage.recodeCount}，
每页大小:${myData.myPage.perPageSize }，
一共${myData.myPage.pageCount}页
<br><br>
<c:forEach begin="${myData.myPage.pageBegin}" end="${myData.myPage.pageEnd}" varStatus="sta"><a href="LoveInHeartActionGetAll?currentPage=${sta.index}">第${sta.index}页</a>
</c:forEach><table align="center" border="1" ><tr><td colspan="6" align="right">---中华爱心捐款查询系统<a href="add.jsp">添加新捐款</a></span></td></tr><tr><td>编号</td><td>姓名</td><td>性别</td><td>捐款金额</td><td>捐款时间</td><td>操作</td></tr><c:forEach items="${myData.loveInHeartList}" var="love"><tr><td>${love.lid}</td><td>${love.lname}</td><td>${love.lsex}</td><td>${love.lmoney}</td><td>${love.ltime}</td><td><a href="LoveInHeartActionDelete?id=${love.lid}">删除</a>&nbsp;<a href="javascript:mydelete(${love.lid})">无刷新删除1</a>&nbsp;<button onclick="mydelete(${love.lid})">无刷新删除2</button></td></tr>
</c:forEach></table><c:forEach begin="${myData.myPage.pageBegin}" end="${myData.myPage.pageEnd}" varStatus="sta"><a href="LoveInHeartActionGetAll?currentPage=${sta.index}">第${sta.index}页</a>
</c:forEach></body>
</html>

最终结果图如下：

有许多不足还请各位大佬指教，谢谢

转载于:https://www.cnblogs.com/liaoyuanping-24/p/9296545.html