JavaWeb项目----实现用户登录、注册、对商品信息进行的添加、删除、修改功能-Toy模板网

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MySQL部分

#创建数据库
create database mydb;
 
 
#创建表
create table t_user
(
	uid int primary key auto_increment,
	username varchar(20),
	password varchar(20),
	phone varchar(11),
	address varchar(50)
);
 
#插入数据
insert into t_user(username,password,phone,address) values('张三','666','18965423548','南阳');
insert into t_user(username,password,phone,address) values('李四','333','18754263548','许昌');
insert into t_user(username,password,phone,address) values('小美','123','18565234759','信阳');
 
 
 
create table t_goods
(
	gid int primary key auto_increment,
	gname varchar(20),
	price double,
	mark varchar(100)
);
 
insert into t_goods(gname,price,mark) values('泡面',4.5,'够香够辣就是这个味！');
insert into t_goods(gname,price,mark) values('火腿',8.5,'肉质细腻Q弹！');
insert into t_goods(gname,price,mark) values('雪碧',3.5,'清爽冰凉随心爽！');

Java部分

在idea中创建有关类

JavaWeb项目----实现用户登录、注册、对商品信息进行的添加、删除、修改功能

web中写jsp页面，index.jsp是首页布局

<html>
<head>
  <title>这是JavaWeb项目</title>
</head>
<body>
<h2>开始学习JavaWeb吧！</h2>
<a href="login.jsp">登录</a>
<a href="zhuce.jsp">注册</a>
</body>
</html>

运行效果如下：

JavaWeb项目----实现用户登录、注册、对商品信息进行的添加、删除、修改功能

登录页面

<html>
<head>
  <title>登录</title>
</head>
<body>
<h2>登录</h2>
<form action="login" method="post">
  账号：<input type="text" name="username" value=""/><br/>
  密码：<input type="password" name="password" value=""/><br/>
  <input type="submit" value="登录">&nbsp;&nbsp;&nbsp;
  <a href="zhuce.jsp">没有账号？请注册</a>
</form>
</body>
</html>

运行效果如下：

JavaWeb项目----实现用户登录、注册、对商品信息进行的添加、删除、修改功能

注册页面

<html>
<head>
    <title>注册</title>
</head>
<body>
<form action="zhuce" method="post">
    账号:<input type="text" name="username" value=""><br>
    密码:<input type="password" name="password" value=""><br>
    电话:<input type="text" name="phone"><br>
    地址:<input type="text" name="address">
    <input type="submit" value="注册">
    <a href="login.jsp">已有帐号？请登录</a>
</form>
</body>
</html>

运行效果如下：

JavaWeb项目----实现用户登录、注册、对商品信息进行的添加、删除、修改功能

登陆正确时跳转到zhuye.jsp主页页面（使用Java脚本获取集合中对象的元素，放html标签中）

<%@ page import="java.util.List" %>
<%@ page import="com.shi.bean.Goods" %><%--
  Created by IntelliJ IDEA.

--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>登录</title>
</head>
<body>
<h2>登陆成功！</h2>
<h3>欢迎来到项目主页</h3>
<table>
    <thead>
    <tr>
        <th>商品编号</th>
        <th>商品名称</th>
        <th>商品价格</th>
        <th>商品说明</th>
    </tr>
    </thead>
    <tbody id="list">
    <%
        //获取session
        HttpSession session1 = request.getSession();
        //从session中取出数据
        List<Goods> goodsList = (List<Goods>) session1.getAttribute("goodsList");
        //遍历集合元素
        for (Goods goods : goodsList) {
    %>
    <!--使用Java脚本获取集合中对象的元素，放html标签中-->
    <tr>
        <td><%=goods.getGid()%>
        </td>
        <td><%=goods.getGname()%>
        </td>
        <td><%=goods.getPrice()%>
        </td>
        <td><%=goods.getMark()%>
        </td>
    </tr>
    <%

        }

    %>

    </tbody>

</table>
</body>
</html>

运行效果如下：

JavaWeb项目----实现用户登录、注册、对商品信息进行的添加、删除、修改功能

在登陆页面，密码或用户名输入错误时跳转到error.jsp再返回login.jsp登陆页面

<html>
<head>
    <title>错误页</title>
</head>
<body>
<h2>出错啦！</h2>
<a href="login.jsp">返回登陆</a>
 
</body>
</html>

效果如图所示：

JavaWeb项目----实现用户登录、注册、对商品信息进行的添加、删除、修改功能

用户实体类代码如下：

package com.shi.bean;
 
public class User {
    private int uid;
    private String username;
    private String password;
    private String phone;
    private String address;
 
    public int getUid() {
        return uid;
    }
 
    public String getUsername() {
        return username;
    }
 
    public String getPassword() {
        return password;
    }
 
    public String getPhone() {
        return phone;
    }
 
    public String getAddress() {
        return address;
    }
 
    public void setUid(int uid) {
        this.uid = uid;
    }
 
    public void setUsername(String username) {
        this.username = username;
    }
 
    public void setPassword(String password) {
        this.password = password;
    }
 
    public void setPhone(String phone) {
        this.phone = phone;
    }
 
    public void setAddress(String address) {
        this.address = address;
    }
 
    @Override
    public String toString() {
        return "User{" +
                "uid=" + uid +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                ", phone='" + phone + '\'' +
                ", address='" + address + '\'' +
                '}';
    }
}

package com.shi.bean;

public class Goods {
    private int gid;
    private String gname;
    private Double price;
    private String mark;

    public int getGid() {
        return gid;
    }

    public void setGid(int gid) {
        this.gid = gid;
    }

    public String getGname() {
        return gname;
    }

    public void setGname(String gname) {
        this.gname = gname;
    }

    public Double getPrice() {
        return price;
    }

    public void setPrice(Double price) {
        this.price = price;
    }

    public String getMark() {
        return mark;
    }

    public void setMark(String mark) {
        this.mark = mark;
    }

    @Override
    public String toString() {
        return "Goods{" +
                "gid=" + gid +
                ", gname='" + gname + '\'' +
                ", price=" + price +
                ", mark='" + mark + '\'' +
                '}';
    }
}

功能逻辑类UserDao

package com.shi.dao;

import com.shi.bean.User;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;


public class UserDao {
    private static String jdbcDriver = "com.mysql.jdbc.Driver";
    private static String jdbcUrl = "jdbc:mysql://localhost:3306/mydb";
    private static String jdbcUser = "root";
    private static String jdbcPwd = "root";

    private Connection con = null; //数据库连接对象
    private PreparedStatement pstm = null; //预处理对象
    private ResultSet rs = null; //结果集对象
    private int row = 0; //增删改受影响的行数

    public User login(String username, String password) {
        User login = null;
        try {
            Class.forName(jdbcDriver);
            con = DriverManager.getConnection(jdbcUrl, jdbcUser, jdbcPwd);
            String sql = "select * from t_user where username=? and password=?";
            pstm = con.prepareStatement(sql);
            pstm.setObject(1, username);
            pstm.setObject(2, password);
            rs = pstm.executeQuery();

            if (rs.next()) {
                //从结果集中取出数据，封装到User对象中
                login = new User();
                login.setUid(rs.getInt("uid"));
                login.setUsername(rs.getString("username"));
                login.setPassword(rs.getString("password"));
                login.setPhone(rs.getString("phone"));
                login.setAddress(rs.getString("Address"));
            }

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (rs != null) {
                    rs.close();
                }
                if (pstm != null) {
                    rs.close();
                }
                if (con != null) {
                    rs.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return login;
    }

    public int add(User user) {
        try {
            Class.forName(jdbcDriver);
            con = DriverManager.getConnection(jdbcUrl, jdbcUser, jdbcPwd);
            String sql = "insert into t_user(username,password,phone,address) values(?,?,?,?)";
            pstm = con.prepareStatement(sql);
            pstm.setObject(1, user.getUsername());
            pstm.setObject(2, user.getPassword());
            pstm.setObject(3, user.getPhone());
            pstm.setObject(4, user.getAddress());

            row = pstm.executeUpdate();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (rs != null) {
                    rs.close();
                }
                if (pstm != null) {
                    rs.close();
                }
                if (con != null) {
                    rs.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return row;

    }
}

功能逻辑类GoodsDao

package com.shi.dao;

import com.shi.bean.Goods;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;


public class GoodsDao {
    //连接数据库的四大参数
    private static String jdbcDriver = "com.mysql.jdbc.Driver";
    private static String jdbcUrl = "jdbc:mysql://localhost:3306/mydb";
    private static String jdbcUser = "root";
    private static String jdbcPwd = "root";

    private Connection con = null; //数据库连接对象
    private PreparedStatement pstm = null; //预处理对象
    private ResultSet rs = null; //结果集对象


    public List<Goods> selectAll() {
        List<Goods> goodsList = new ArrayList<>();
        try {
            Class.forName(jdbcDriver);
            con = DriverManager.getConnection(jdbcUrl, jdbcUser, jdbcPwd);
            String sql = "select*from t_goods";
            pstm = con.prepareStatement(sql);
            rs = pstm.executeQuery();
            while (rs.next()) {
                Goods goods = new Goods();
                //从结果集中获取数据，封装到Goods对象中
                goods.setGid(rs.getInt("gid"));
                goods.setGname(rs.getString("gname"));
                goods.setPrice(rs.getDouble("price"));
                goods.setMark(rs.getString("mark"));

                //把当前行对应的对象存储到集合中
                goodsList.add(goods);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (rs != null) {
                    rs.close();
                }
                if (pstm != null) {
                    rs.close();
                }
                if (con != null) {
                    rs.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return goodsList;
    }
}

Login逻辑代码

package com.shi.dao;

import com.shi.bean.Goods;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

/**
 * @author 史佳宁  2023/2/20  16:36
 * @version 1.0
 */
public class GoodsDao {
    //连接数据库的四大参数
    private static String jdbcDriver = "com.mysql.jdbc.Driver";
    private static String jdbcUrl = "jdbc:mysql://localhost:3306/mydb";
    private static String jdbcUser = "root";
    private static String jdbcPwd = "root";

    private Connection con = null; //数据库连接对象
    private PreparedStatement pstm = null; //预处理对象
    private ResultSet rs = null; //结果集对象


    public List<Goods> selectAll() {
        List<Goods> goodsList = new ArrayList<>();
        try {
            Class.forName(jdbcDriver);
            con = DriverManager.getConnection(jdbcUrl, jdbcUser, jdbcPwd);
            String sql = "select*from t_goods";
            pstm = con.prepareStatement(sql);
            rs = pstm.executeQuery();
            while (rs.next()) {
                Goods goods = new Goods();
                //从结果集中获取数据，封装到Goods对象中
                goods.setGid(rs.getInt("gid"));
                goods.setGname(rs.getString("gname"));
                goods.setPrice(rs.getDouble("price"));
                goods.setMark(rs.getString("mark"));

                //把当前行对应的对象存储到集合中
                goodsList.add(goods);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (rs != null) {
                    rs.close();
                }
                if (pstm != null) {
                    rs.close();
                }
                if (con != null) {
                    rs.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return goodsList;
    }
}

Zhuce逻辑代码

package com.shi.servlet;

import com.shi.bean.User;
import com.shi.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;


//设置当前类用来处理/register的请求
@WebServlet("/zhuce")
public class Zhuce extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
      doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
       //1.设置编码
        req.setCharacterEncoding("utf-8");
        resp.setCharacterEncoding("utf-8");
        resp.setContentType("text/html;charset=UTF-8");
        //2.获取请求参数
        String username=req.getParameter("username");
        String password=req.getParameter("password");
        String phone=req.getParameter("phone");
        String address=req.getParameter("address");
        //封装：把上面所有的变量装载到User对象中
        User user=new User();
        user.setUsername(username);
        user.setPassword(password);
        user.setPhone(phone);
        user.setAddress(address);


        //3:执行业务处理---jdbc的操作
        UserDao userDao=new UserDao();
        int row = userDao.add(user);

        if(row>0){

            resp.sendRedirect("login.jsp");//指定跳转的页面
        }else {

            resp.sendRedirect("error.jsp");
        }


    }
}

SelectAllGoods逻辑代码

package com.shi.servlet;

import com.shi.bean.Goods;
import com.shi.dao.GoodsDao;

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 javax.servlet.http.HttpSession;
import java.io.IOException;
import java.util.List;


@WebServlet("/selectAllGoods")
public class SelectAllGoods extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        //查询所有商品信息
        GoodsDao goodsDao=new GoodsDao();
        List<Goods> goodsList=goodsDao.selectAll();
        System.out.println(goodsList);

        //把数据传递到前端页面
        //通过request获取session对象，该对象可以向前端传输数据内容
        HttpSession session = req.getSession();
        //向session中存入商品信息集合

        session.setAttribute("goodsList",goodsList);

        //登陆成功，跳转到主页
        resp.sendRedirect("zhuye.jsp");//跳转到指定页面
    }
}

登录成功后跳转到主页并展示数据库的商品信息效果如下：

JavaWeb项目----实现用户登录、注册、对商品信息进行的添加、删除、修改功能

重新查看展示数据，请求转发给SelectAllGoods

package com.shi.servlet;

import com.shi.bean.Goods;
import com.shi.dao.GoodsDao;

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 javax.servlet.http.HttpSession;
import java.io.IOException;
import java.util.List;


@WebServlet("/selectAllGoods")
public class SelectAllGoods extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        //查询所有商品信息
        GoodsDao goodsDao=new GoodsDao();
        List<Goods> goodsList=goodsDao.selectAll();
        System.out.println(goodsList);

        //把数据传递到前端页面
        //通过request获取session对象，该对象可以向前端传输数据内容
        HttpSession session = req.getSession();
        //向session中存入商品信息集合

        session.setAttribute("goodsList",goodsList);

        //登陆成功，跳转到主页
        resp.sendRedirect("zhuye.jsp");//跳转到指定页面
    }
}

主页代码

<%@ page import="java.util.List" %>
<%@ page import="com.shi.bean.Goods" %><%--
  Created by IntelliJ IDEA.
  User: ss
  Date: 2023/2/20
  Time: 14:46
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!--导入JSTL的核心类库-->
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <title>主页</title>
</head>
<body>
<h2>欢迎来自${user.address}的${user.username}访问项目主页</h2>
<a href="addGoods.jsp">添加商品</a>
<table>
    <thead>
    <tr>
        <th>商品编号</th>
        <th>商品名称</th>
        <th>商品价格</th>
        <th>商品说明</th>
    </tr>
    </thead>
    <tbody id="list">
    <!--items:要遍历的集合对象（写EL表达式）-->
    <c:forEach items="${goodsList}" var="goods">
        <tr>
            <td>${goods.gid}</td>
            <td>${goods.gname}</td>
            <td>${goods.price}</td>
            <td>${goods.mark}</td>
            <td>
                <a href="findById?gid=${goods.gid}">修改</a>
                <a href="dell?gid=${goods.gid}">删除</a>
            </td>
        </tr>
    </c:forEach>


    </tbody>

</table>
</body>
</html>

返回到登录页面登录商品页面

JavaWeb项目----实现用户登录、注册、对商品信息进行的添加、删除、修改功能

商品添加

添加时跳转的页面，代码如下

<%--
  Created by IntelliJ IDEA.
  User: ss
  Date: 2023/2/24
  Time: 11:52
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>商品信息添加</title>
</head>
<body>
<h2>商品信息录入</h2>
<form action="addGoods" method="post">
    商品名称：<input type="text"name="gname" value="" placeholder="商品名称"><br/>
    商品价格：<input type="number" step="0.01" name="price" value="" placeholder="商品价格"><br/>
    商品说明：<input type="textr" name="mark" value="" placeholder="商品说明"><br/>
    <input type="submit" value="添加">
</form>

</body>
</html>

效果如图

JavaWeb项目----实现用户登录、注册、对商品信息进行的添加、删除、修改功能

功能代码

package com.shi.servlet;

import com.shi.bean.Goods;
import com.shi.dao.GoodsDao;

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("/addGoods")
public class AddGoods extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
     req.setCharacterEncoding("UTF-8");
     resp.setCharacterEncoding("UTF-8");

        Goods goods=new Goods();
        goods.setGname(req.getParameter("gname"));
        goods.setPrice(Double.parseDouble(req.getParameter("price"))); //获取字符串数字转化为double数据
        goods.setMark(req.getParameter("mark"));

        GoodsDao goodsDao=new GoodsDao();
        int row=goodsDao.add(goods);

        if (row>0){
            req.getRequestDispatcher("selectAllGoods").forward(req,resp);
        }else {
            req.setAttribute("error_msg","添加商品信息失败！");
            req.getRequestDispatcher("error.jsp").forward(req,resp);
        }
    }
}

商品修改

页面代码如下

<%--
  Created by IntelliJ IDEA.
  User: \ss
  Date: 2023/2/25
  Time: 15:14
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>商品信息修改</title>
</head>
<body>
<h2>商品信息录入</h2>
<form action="updateGoods" method="post">
    商品编号：<input type="text"name="gid" value="${goods.gid}" placeholder="商品编号" readonly="readonly"><br/>
    商品名称：<input type="text"name="gname" value="${goods.gname}" placeholder="商品名称"><br/>
    商品价格：<input type="number" step="0.01" name="price" value="${goods.price}" placeholder="商品价格"><br/>
    商品说明：<input type="textr" name="mark" value="${goods.mark}" placeholder="商品说明"><br/>
    <input type="submit" value="修改">
</form>

</body>
</html>

获取当前点击修改商品信息的id，向页面传输id

package com.shi.servlet; 

import com.shi.bean.Goods;
import com.shi.dao.GoodsDao;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;

@WebServlet("/findById")
public class FindGoodsById extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);

    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        int gid=Integer.parseInt(request.getParameter("gid"));
        //根据gid查询商品信息
        GoodsDao goodsDao=new GoodsDao();
        Goods goods = goodsDao.selectById(gid);

        if (goods!=null){
            //把数据存储到request域对象中，然后请求转发到页面
            request.setAttribute("goods",goods);
            request.getRequestDispatcher("showGoods.jsp").forward(request,response);
        }else {
            //登陆失败，跳转到错误页面
            request.setAttribute("error_msg","修改页面出现异常！");
            request.getRequestDispatcher("error.jsp").forward(request,response);
        }

    }
}

实现代码如下

package com.shi.servlet;

import com.shi.bean.Goods;

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("/updateGoods")
public class UpdateGoods extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf-8");
        resp.setCharacterEncoding("utf-8");
        //获取表单去哦那个球的数据，封装到goods对象中
        Goods goods=new Goods();
        goods.setGid(Integer.parseInt(req.getParameter("gid")));
        goods.setGname(req.getParameter("gname"));
        goods.setPrice(Double.parseDouble(req.getParameter("price")));
        goods.setMark(req.getParameter("mark"));

        System.out.println(goods);
    }
}

逻辑代码

  public int add(Goods goods) {
        try {
            Class.forName(jdbcDriver);
            con = DriverManager.getConnection(jdbcUrl, jdbcUser, jdbcPwd);
            String sql = "insert into t_goods(gname,price,mark) values(?,?,?)";
            pstm = con.prepareStatement(sql);
            pstm.setObject(1, goods.getGname());
            pstm.setObject(2, goods.getPrice());
            pstm.setObject(3, goods.getMark());
            row = pstm.executeUpdate();

        } catch (Exception e) {
            e.printStackTrace();
        }
        try {
            if (rs != null) {
                rs.close();
            }
            if (pstm != null) {
                rs.close();
            }
            if (con != null) {
                rs.close();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return row;

    }

商品删除

也是获取当前商品id，根据id进行修改操作

GoodsDao逻辑代码

 public int deleteById(int gid) {
        try {
            Class.forName(jdbcDriver);
            con = DriverManager.getConnection(jdbcUrl, jdbcUser, jdbcPwd);
            String sql = "delete from t_goods where gid=?";
            pstm = con.prepareStatement(sql);
            pstm.setObject(1, gid);
            row=pstm.executeUpdate();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {

            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return row;
    }

select实现功能代码文章来源地址https://www.toymoban.com/news/detail-502556.html

package com.shi.servlet;

import com.shi.dao.GoodsDao;

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("/dell")
public class DellGoods extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        int gid=Integer.parseInt(req.getParameter("gid"));
        //根据id执行数据库的删除
        GoodsDao goodsDao=new GoodsDao();
        int row=goodsDao.deleteById(gid);
        if (row>0){
            req.getRequestDispatcher("selectAllGoods").forward(req,resp);
        }else {
            //请求转发，查询所有商品信息（刷新）
            req.setAttribute("error_msg","删除出现了问题！");
            req.getRequestDispatcher("error.jsp").forward(req,resp);
        }
    }
}

到了这里，关于JavaWeb项目----实现用户登录、注册、对商品信息进行的添加、删除、修改功能的文章就介绍完了。如果您还想了解更多内容，请在右上角搜索TOY模板网以前的文章或继续浏览下面的相关文章，希望大家以后多多支持TOY模板网！