12-13 库存信息管理系统

1.首先是建立 商品类 与上一周的课程管理体统类似 

package com.hjf.entity;

public class Course {

    private int id;
    private String name;
    private String shengc;
    private String xingh;
    private String guig;
    private String shul;
    private String riq;
    private String shij;
    private String ruk;
    private String songh;
    public String getsongh() {
        return songh;
    }
    public void setsongh(String songh) {
        this.songh = songh;
    }
    public String getruk() {
        return ruk;
    }
    public void setruk(String ruk) {
        this.ruk = ruk;
    }
    public String getshij() {
        return shij;
    }
    public void setshij(String shij) {
        this.shij = shij;
    }
    public String getriq() {
        return riq;
    }
    public void setriq(String riq) {
        this.riq = riq;
    }
    public String getshul() {
        return shul;
    }
    public void setshul(String shul) {
        this.shul = shul;
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getshengc() {
        return shengc;
    }
    public void setshengc(String shengch) {
        this.shengc = shengch;
    }
    public String getxingh() {
        return xingh;
    }
    public void setxingh(String xingh) {
        this.xingh = xingh;
    }
    public String getguig() {
        return guig;
    }
    public void setguig(String guig) {
        this.guig = guig;
    }
    
    public Course() {
        // TODO 自动生成的构造函数存根
    }

    public Course(int id, String name, String shengc, String xingh,String guig,String shul,String riq,String shij,String ruk,String songh) {
        this.id = id;
        this.name = name;
        this.shengc = shengc;
        this.xingh = xingh;
        this.guig = guig;
        this.shul = shul;
        this.riq = riq;
        this.shij = shij;
        this.ruk = ruk;
        this.songh = songh;
    }
    
    public Course(String name, String shengc, String xingh,String guig,String shul,String riq,String shij,String ruk,String songh) {
        this.name = name;
        this.shengc = shengc;
        this.xingh = xingh;
        this.guig = guig;
        this.shul = shul;
        this.riq = riq;
        this.shij = shij;
        this.ruk = ruk;
        this.songh = songh;
    }
}

2.然后是dao层的增删改查

package com.hjf.dao;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

import com.hjf.entity.Course;
import com.hjf.util.DBUtil;

/**
 * 课程Dao
 * Dao层操作数据
 * @author xie
 * 
 *
 */
public class CourseDao {

    /**
     * 添加
     * @param course
     * @return
     */
    public boolean add(Course course) {
        String sql = "insert into course(name, shengc, xingh,guig,shul,riq,shij,ruk,songh) values('" + course.getName() + "','" + course.getshengc() + "','" + course.getxingh() + "','" + course.getguig()+ "','" + course.getshul() + "','" + course.getriq()+ "','" + course.getshij()+ "','" + course.getruk()+ "','" + course.getsongh() + "')";
        Connection conn = DBUtil.getConn();
        Statement state = null;
        boolean f = false;
        int a = 0;
        
        try {
            state = conn.createStatement();
            state.executeUpdate(sql);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(state, conn);
        }
        
        if (a > 0) {
            f = true;
        }
        return f;
    }

    /**
     * 删除
     * 
     * @param id
     * @return
     */
    public boolean delete (int id) {
        boolean f = false;
        String sql = "delete from course where id='" + id + "'";
        Connection conn = DBUtil.getConn();
        Statement state = null;
        int a = 0;
        
        try {
            state = conn.createStatement();
            a = state.executeUpdate(sql);
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(state, conn);
        }
        
        if (a > 0) {
            f = true;
        }
        return f;
    }

    /**
     * 修改
     * @param name
     * @param pass
     */
    public boolean update(Course course) {
        String sql = "update course set name='" + course.getName() + "', shengc='" + course.getshengc() + "', xingh='" + course.getxingh()+"',guig='" + course.getguig()+"',shul='" + course.getshul()+"',riq='" + course.getriq()
        +"',shij='" + course.getshij()+"',ruk='" + course.getruk()+"',songh='" + course.getsongh()            + "' where id='" + course.getId() + "'";
        Connection conn = DBUtil.getConn();
        Statement state = null;
        boolean f = false;
        int a = 0;

        try {
            state = conn.createStatement();
            a = state.executeUpdate(sql);
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(state, conn);
        }
        
        if (a > 0) {
            f = true;
        }
        return f;
    }
    
    /**
    
     * @param name
     * @return
     */
    public boolean name(String name) {
        boolean flag = false;
        String sql = "select name from course where name = '" + name + "'";
        Connection conn = DBUtil.getConn();
        Statement state = null;
        ResultSet rs = null;
        
        try {
            state = conn.createStatement();
            rs = state.executeQuery(sql);
            while (rs.next()) {
                flag = true;
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(rs, state, conn);
        }
        return flag;
    }
    
    /**
     * 通过ID得到类
     * @param id
     * @return
     */
    public Course getCourseById(int id) {
        String sql = "select * from course where id ='" + id + "'";
        Connection conn = DBUtil.getConn();
        Statement state = null;
        ResultSet rs = null;
        Course course = null;
        
        try {
            state = conn.createStatement();
            rs = state.executeQuery(sql);
            while (rs.next()) {
                String name = rs.getString("name");
                String shengc = rs.getString("shengc");
                String xingh = rs.getString("xingh");
                String guig = rs.getString("guig");
                String shul = rs.getString("shul");
                String riq = rs.getString("riq");
                String shij = rs.getString("shij");
                String ruk = rs.getString("ruk");
                String songh = rs.getString("songh");
                course = new Course(id, name, shengc,xingh,guig,shul,riq,shij,ruk,songh);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(rs, state, conn);
        }
        
        return course;
    }
    
    /**
     * 通过name得到Course
     * @param name
     * @return
     */
    public Course getCourseByName(String name) {
        String sql = "select * from course where name ='" + name + "'";
        Connection conn = DBUtil.getConn();
        Statement state = null;
        ResultSet rs = null;
        Course course = null;
        
        try {
            state = conn.createStatement();
            rs = state.executeQuery(sql);
            while (rs.next()) {
                int id = rs.getInt("id");
                
                String shengc = rs.getString("shengc");
                String xingh = rs.getString("xingh");
                String guig = rs.getString("guig");
                String shul = rs.getString("shul");
                String riq = rs.getString("riq");
                String shij = rs.getString("shij");
                String ruk = rs.getString("ruk");
                String songh = rs.getString("songh");
                course = new Course(id, name, shengc,xingh,guig,shul,riq,shij,ruk,songh);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(rs, state, conn);
        }
        
        return course;
    }
    
    /**
     * 查找
     
     */
    public List<Course> search(String name, String riq,String songh) {
        String sql = "select * from course where 1=1 ";
        if (name != "") {
            sql += "and name like '%" + name + "%'";
        }
        if (riq != "") {
            sql += "and riq like '%" + riq+ "%'";
        }
        if (songh != "") {
            sql += "and songh like '%" + songh+ "%'";
        }
        List<Course> list = new ArrayList<>();
        Connection conn = DBUtil.getConn();
        Statement state = null;
        ResultSet rs = null;

        try {
            state = conn.createStatement();
            rs = state.executeQuery(sql);
            Course bean = null;
            while (rs.next()) {
                int id = rs.getInt("id");
                String name2 = rs.getString("name");
                String shengc2 = rs.getString("shengc");
                String xingh2 = rs.getString("xingh");
                String guig2 = rs.getString("guig");
                String shul2 = rs.getString("shul");
                String riq2 = rs.getString("riq");
                String shij2 = rs.getString("shij");
                String ruk2 = rs.getString("ruk");
                String songh2 = rs.getString("songh");
                
                bean = new Course(id, name2, shengc2,xingh2,guig2,shul2,riq2,shij2,ruk2,songh2);
                list.add(bean);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(rs, state, conn);
        }
        
        return list;
    }
    
    /**
     * 全部数据
    
     */
    public List<Course> list() {
        String sql = "select * from course";
        List<Course> list = new ArrayList<>();
        Connection conn = DBUtil.getConn();
        Statement state = null;
        ResultSet rs = null;

        try {
            state = conn.createStatement();
            rs = state.executeQuery(sql);
            Course bean = null;
            while (rs.next()) {
                int id = rs.getInt("id");
                String name2 = rs.getString("name");
                String shengc2 = rs.getString("shengc");
                String xingh2 = rs.getString("xingh");
                String guig2 = rs.getString("guig");
                String shul2 = rs.getString("shul");
                String riq2 = rs.getString("riq");
                String shij2 = rs.getString("shij");
                String ruk2 = rs.getString("ruk");
                String songh2 = rs.getString("songh");
                
                bean = new Course(id, name2, shengc2,xingh2,guig2,shul2,riq2,shij2,ruk2,songh2);
                list.add(bean);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(rs, state, conn);
        }
        
        return list;
    }

}

3.service接口

package com.hjf.service;

import java.util.List;

import com.hjf.dao.CourseDao;
import com.hjf.entity.Course;

/**
 * CourseService
 * 服务层
 * @author Hu
 *
 */
public class CourseService {

    CourseDao cDao = new CourseDao();
    
    /**
     * 添加
     * @param course
     * @return
     */
    public boolean add(Course course) {
        boolean f = false;
        if(!cDao.name(course.getName())) {
            cDao.add(course);
            f = true;
        }
        return f;
    }
    
    /**
     * 删除
     */
    public void del(int id) {
        cDao.delete(id);
    }
    
    /**
     * 修改
     * @return 
     */
    public void update(Course course) {
        cDao.update(course);
    }
    
    /**
     * 通过ID得到一个Course
     * @return 
     */
    public Course getCourseById(int id) {
        return cDao.getCourseById(id);
    }

    /**
     * 通过Name得到一个Course
     * @return 
     */
    public Course getCourseByName(String name) {
        return cDao.getCourseByName(name);
    }
    
    /**
     * 查找
     * @return 
     */
    public List<Course> search(String name,String riq,String songh) {
        return cDao.search( name,riq,songh);
    }
    
    /**
     * 全部数据
     * @return 
     */
    public List<Course> list() {
        return cDao.list();
    }
}

4.severlet 层 不用更改

package com.hjf.servlet;

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.hjf.entity.Course;
import com.hjf.service.CourseService;

@WebServlet("/CourseServlet")
public class CourseServlet extends HttpServlet {
    
    private static final long serialVersionUID = 1L;

    CourseService service = new CourseService();
    
    /**
     * 方法选择
     */
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf-8");
        String method = req.getParameter("method");
        if ("add".equals(method)) {
            add(req, resp);
        } else if ("del".equals(method)) {
            del(req, resp);
        } else if ("update".equals(method)) {
            update(req, resp);
        } else if ("search".equals(method)) {
            search(req, resp);
        } else if ("getcoursebyid".equals(method)) {
            getCourseById(req, resp);
        } else if ("getcoursebyname".equals(method)) {
            getCourseByName(req, resp);
        } else if ("list".equals(method)) {
            list(req, resp);
        }
    }

    /**
     * 添加
     * @param req
     * @param resp
     * @throws IOException 
     * @throws ServletException 
     */
    private void add(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException {
        req.setCharacterEncoding("utf-8");
        String name = req.getParameter("name");
        String shengc = req.getParameter("shengc");
        String xingh = req.getParameter("xingh");
        String guig = req.getParameter("guig");
        String shul = req.getParameter("shul");
        String riq = req.getParameter("riq");
        String shij = req.getParameter("shij");
        String ruk = req.getParameter("ruk");
        String songh = req.getParameter("songh");
        
        Course course = new Course( name, shengc,xingh,guig,shul,riq,shij,ruk,songh);
        
        //添加后消息显示
        if(service.add(course)) {
            req.setAttribute("message", "添加成功");
            req.getRequestDispatcher("add.jsp").forward(req,resp);
        } else {
            req.setAttribute("message", "商品名称重复，请重新录入");
            req.getRequestDispatcher("add.jsp").forward(req,resp);
        }
    }
    
    /**
     * 全部
     * @param req
     * @param resp
     * @throws ServletException 
     */
    private void list(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
        req.setCharacterEncoding("utf-8");
        List<Course> courses = service.list();
        req.setAttribute("courses", courses);
        req.getRequestDispatcher("list.jsp").forward(req,resp);
    }

    /**
     * 通过ID得到Course
     * @param req
     * @param resp
     * @throws ServletException 
     */
    private void getCourseById(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
        req.setCharacterEncoding("utf-8");
        int id = Integer.parseInt(req.getParameter("id"));
        Course course = service.getCourseById(id);
        req.setAttribute("course", course);
        req.getRequestDispatcher("detail2.jsp").forward(req,resp);
    }

    /**
     * 通过名字查找
     * 跳转至删除
     * @param req
     * @param resp
     * @throws IOException
     * @throws ServletException 
     */
    private void getCourseByName(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
        req.setCharacterEncoding("utf-8");
        String name = req.getParameter("name");
        Course course = service.getCourseByName(name);
        if(course == null) {
            req.setAttribute("message", "查无此商品！");
            req.getRequestDispatcher("del.jsp").forward(req,resp);
        } else {
            req.setAttribute("course", course);
            req.getRequestDispatcher("detail.jsp").forward(req,resp);
        }
    }
    
    /**
     * 删除
     * @param req
     * @param resp
     * @throws IOException
     * @throws ServletException 
     */
    private void del(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
        req.setCharacterEncoding("utf-8");
        int id = Integer.parseInt(req.getParameter("id"));
        service.del(id);
        req.setAttribute("message", "删除成功！");
        req.getRequestDispatcher("del.jsp").forward(req,resp);
    }
    
    /**
     * 修改
     * @param req
     * @param resp
     * @throws IOException
     * @throws ServletException 
     */
    private void update(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
        req.setCharacterEncoding("utf-8");
        int id = Integer.parseInt(req.getParameter("id"));
        String name = req.getParameter("name");
        String shengc = req.getParameter("shengc");
        String xingh = req.getParameter("xingh");
        String guig = req.getParameter("guig");
        String shul = req.getParameter("shul");
        String riq = req.getParameter("riq");
        String shij = req.getParameter("shij");
        String ruk = req.getParameter("ruk");
        String songh = req.getParameter("songh");
        Course course = new Course(id, name, shengc,xingh,guig,shul,riq,shij,ruk,songh);
        
        service.update(course);
        req.setAttribute("message", "修改成功");
        req.getRequestDispatcher("CourseServlet?method=list").forward(req,resp);
    }
    
    /**
     * 查找
     * @param req
     * @param resp
     * @throws ServletException 
     */
    private void search(HttpServletRequest req, HttpServletResponse resp) throws IOException, ServletException{
        req.setCharacterEncoding("utf-8");
        String name = req.getParameter("name");
        String riq = req.getParameter("riq");
        String songh = req.getParameter("songh");
        List<Course> courses = service.search( name, riq,songh);
        req.setAttribute("courses", courses);
        req.getRequestDispatcher("searchlist.jsp").forward(req,resp);
    }
}

5.数据可的连接

package com.hjf.util;
//数据库连接
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

/**
 * 数据库连接工具
 * @author Zheng
 *
 */
public class DBUtil {
    
    public static String db_url = "jdbc:mysql://localhost:3306/course?useSSL=false";
    public static String db_user = "root";
    public static String db_pass = "root";
    
    public static Connection getConn () {
        Connection conn = null;
        
        try {
            Class.forName("com.mysql.jdbc.Driver");//加载驱动
            conn = DriverManager.getConnection(db_url, db_user, db_pass);
        } catch (Exception e) {
            e.printStackTrace();
        }
        
        return conn;
    }
    
    /**
     * 关闭连接
     * @param state
     * @param conn
     */
    public static void close (Statement state, Connection conn) {
        if (state != null) {
            try {
                state.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        
        if (conn != null) {
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
    
    public static void close (ResultSet rs, Statement state, Connection conn) {
        if (rs != null) {
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        
        if (state != null) {
            try {
                state.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        
        if (conn != null) {
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

}

数据库的建立

到这里 Java的代码就完成了

下面是网页界面 的代码 

1首先是主界面

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>首页</title>
<style>
    .a{
        font-size: 26px;
        margin-top: 20px;
    }
</style>
</head>
<body>
    <div align="center">
        <h1 style="color: red;">库存信息管理系统</h1>
        <div class="a">
            <a href="add.jsp">商品信息录入</a>
        </div>
        <div class="a">
            <a href="CourseServlet?method=list">商品信息修改</a>
        </div>
        <div class="a">
            <a href="del.jsp">商品信息删除</a>
        </div>
        <div class="a">
            <a href="search.jsp">商品信息查询</a>
        </div>
    </div>
</body>
</html>

2.增加界面 

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<style>
    .a{
        margin-top: 20px;
    }
    .b{
        font-size: 20px;
         160px;
        color: white;
        background-color: greenyellow;
    }
</style>
</head>
<body>
    <%
         Object message = request.getAttribute("message");
         if(message!=null && !"".equals(message)){
     
    %>
         <script type="text/javascript">
              alert("<%=request.getAttribute("message")%>");
         </script>
    <%} %>
    <div align="center">
        <h1 style="color: red;">商品入库</h1>
        <a href="index.jsp">返回主页</a>
        <form action="CourseServlet?method=add" method="post" onsubmit="return check()">
            <div class="a">
                商品名称<input type="text" id="name" name="name"/>
            </div>
            <div class="a">
                生产厂家<input type="text" id="shengc" name="shengc" />
            </div>
            <div class="a">
                型号<input type="text" id="xingh" name="xingh" />
            </div>
            <div class="a">
                规格<input type="text" id="guig" name="guig" />
            </div>
            <div class="a">
                数量<input type="text" id="shul" name="shul" />
            </div>
            <div class="a">
                日期<input type="text" id="riq" name="riq" />
            </div>
            <div class="a">
                时间<input type="text" id="shij" name="shij" />
            </div>
            <div class="a">
                入库单位<input type="text" id="ruk" name="ruk" />
            </div>
            <div class="a">
                送货人<input type="text" id="songh" name="songh" />
            </div>
            <div class="a">
                <button type="submit" class="b">保&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;存</button>
            </div>
        </form>
    </div>
    <script type="text/javascript">
        function check() {
            var name = document.getElementById("name");;
            var shengc = document.getElementById("shengc");
            var xingh = document.getElementById("xingh");
            var guig=document.getElementById("guig");
            var shul=document.getElementById("shul");
            var riq=document.getElementById("riq");
            var ruk=document.getElementById("ruk");
            var songh=document.getElementById("songh")
            //非空
            if(name.value == '') {
                alert('商品名称为空');
                name.focus();
                return false;
            }
            if(shengc.value == '') {
                alert('生产场地为空');
                shengc.focus();
                return false;
            }
            if(xingh.value == '') {
                alert('型号为空');
                xingh.focus();
                return false;
            }
            if(guig.value == '') {
                alert('规格为空');
                guig.focus();
                return false;
            }
            if(shul.value == '') {
                alert('shul为空');
                shul.focus();
                return false;
            }
            if(riq.value == '') {
                alert('上课地点为空');
                riq.focus();
                return false;
            }
            if(shij.value == '') {
                alert('课程名称为空');
                shij.focus();
                return false;
            }
            if(ruk.value == '') {
                alert('教师为空');
                ruk.focus();
                return false;
            }
            if(songh.value == '') {
                alert('上课地点为空');
                songh.focus();
                return false;
            }
        }
        </script>    
            </body>
            </html>
        

3.删除界面

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<style>
    .a{
        margin-top: 20px;
    }
    .b{
        font-size: 20px;
         160px;
        color: white;
        background-color: greenyellow;
    }
</style>
</head>
<body>
    <%
         Object message = request.getAttribute("message");
         if(message!=null && !"".equals(message)){
     
    %>
         <script type="text/javascript">
              alert("<%=request.getAttribute("message")%>");
         </script>
    <%} %>
    <div align="center">
        <h1 style="color: red;">商品信息删除</h1>
        <a href="index.jsp">返回主页</a>
        <form action="CourseServlet?method=getcoursebyname" method="post" onsubmit="return check()">
            <div class="a">
                商品名称<input type="text" id="name" name="name"/>
            </div>
            <div class="a">
                <button type="submit" class="b">查&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;找</button>
            </div>
        </form>
    </div>
    <script type="text/javascript">
        function check() {
            var name = document.getElementById("name");;
            
            //非空
            if(name.value == '') {
                alert('商品名称为空');
                name.focus();
                return false;
            }
        }
    </script>
</body>
</html>

删除前的显示界面

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<style>
    .a{
        margin-top: 20px;
    }
    .b{
        font-size: 20px;
         160px;
        color: white;
        background-color: greenyellow;
    }
</style>
</head>
<body>
    <%
         Object message = request.getAttribute("message");
         if(message!=null && !"".equals(message)){
     
    %>
         <script type="text/javascript">
              alert("<%=request.getAttribute("message")%>");
         </script>
    <%} %>
    <div align="center">
        <h1 style="color: red;">商品信息删除</h1>
        <a href="index.jsp">返回主页</a>
        <form action="CourseServlet?method=getcoursebyname" method="post" onsubmit="return check()">
            <div class="a">
                商品名称<input type="text" id="name" name="name"/>
            </div>
            <div class="a">
                <button type="submit" class="b">查&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;找</button>
            </div>
        </form>
    </div>
    <script type="text/javascript">
        function check() {
            var name = document.getElementById("name");;
            
            //非空
            if(name.value == '') {
                alert('商品名称为空');
                name.focus();
                return false;
            }
        }
    </script>
</body>
</html>

修改界面

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<style>
    .a{
        margin-top: 20px;
    }
    .b{
        font-size: 20px;
         160px;
        color: white;
        background-color: greenyellow;
    }
</style>
</head>
<body>
    <%
         Object message = request.getAttribute("message");
         if(message!=null && !"".equals(message)){
     
    %>
         <script type="text/javascript">
              alert("<%=request.getAttribute("message")%>");
         </script>
    <%} %>
    <div align="center">
        <h1 style="color: red;">商品信息修改</h1>
        <a href="index.jsp">返回主页</a>
        <form action="CourseServlet?method=update" method="post" onsubmit="return check()">
            <div class="a">
                商品名称<input type="text" id="name" name="name" value="${course.name}"/>
            </div>
            <div class="a">
                生产商家<input type="text" id="shengc" name="shengc" value="${course.shengc}"/>
            </div>
            <div class="a">
                 型号<input type="text" id="xingh" name="xingh" value="${course.xingh}"/>
            </div>
            <div class="a">
                 规格<input type="text" id="guig" name="guig" value="${course.guig}"/>
            </div>
            <div class="a">
                数量<input type="text" id="shul" name="shul" value="${course.shul}"/>
            </div>
            <div class="a">
                 日期<input type="text" id="riq" name="riq" value="${course.riq}"/>
            </div>
            <div class="a">
                 时间<input type="text" id="shij" name="shij" value="${course.shij}"/>
            </div>
            <div class="a">
                 入库单为<input type="text" id="ruk" name="ruk" value="${course.ruk}"/>
            </div>
            <div class="a">
                送货人<input type="text" id="songh" name="songh" value="${course.songh}"/>
            </div>
            <input type="hidden" id="id" name="id" value="${course.id}"/>
            <div class="a">
                <button type="submit" class="b">修&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;改</button>
            </div>
        </form>
    </div>
    <script type="text/javascript">
        function check() {
            var name = document.getElementById("name");;
            var shengc = document.getElementById("shengc");
            var xingh = document.getElementById("xingh");
            var guig=document.getElementById("guig");
            var shul=document.getElementById("shul");
            var riq=document.getElementById("riq");
            var ruk=document.getElementById("ruk");
            var songh=document.getElementById("songh")
            
        }
    </script>
</body>
</html>

显示界面

<%@ 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>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<style>
    .a{
        margin-top: 20px;
    }
    .b{
        font-size: 20px;
         160px;
        color: white;
        background-color: greenyellow;
    }
    .tb, td {
        border: 1px solid black;
        font-size: 22px;
    }
</style>
</head>
<body>
    <%
         Object message = request.getAttribute("message");
         if(message!=null && !"".equals(message)){
     
    %>
         <script type="text/javascript">
              alert("<%=request.getAttribute("message")%>");
         </script>
    <%} %>
    <div align="center">
        <h1 style="color: red;">商品信息列表</h1>
        <a href="index.jsp">返回主页</a>
        <table class="tb">
            <tr>
                <td>id</td>
                <td>商品名称</td>
                <td>型号</td>
                <td>规格</td>
                <td>数量</td>
                <td>日期</td>
                <td>时间</td>
                <td>入库单位</td>
                <td>送货人</td>
                <td align="center" colspan="2">操作</td>
            </tr>
            <c:forEach items="${courses}" var="item">
                <tr>
                    <td>${item.id}</td>
                    <td>${item.name}</td>
                    <td>${item.xingh}</td>
                    <td>${item.guig}</td>
                    <td>${item.riq}</td>
                    <td>${item.shij}</td>
                    <td>${item.ruk}</td>
                    <td>${item.songh}</td>
                    
                    <td><a href="CourseServlet?method=getcoursebyid&id=${item.id}">修改</a></td>
                </tr>
            </c:forEach>
        </table>
    </div>
</body>
</html>

搜索 检索 模糊搜索加二面

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<style>
    .a{
        margin-top: 20px;
    }
    .b{
        font-size: 20px;
         160px;
        color: white;
        background-color: greenyellow;
    }
</style>
</head>
<body>
    <div align="center">
        <h1 style="color: red;">商品信息查询</h1>
        <a href="index.jsp">返回主页</a>
        <form action="CourseServlet?method=search" method="post" onsubmit="return check()">
            <div class="a">
                商品名称<input type="text" id="name" name="name"/>
            </div>
            <div class="a">
                日期<input type="text" id="riq" name="riq" />
            </div>
            <div class="a">
                送货人<input type="text" id="songh" name="songh" />
            </div>
            <div class="a">
                <button type="submit" class="b">查&nbsp;&nbsp;&nbsp;询</button>
            </div>
        </form>
    </div>
    <script type="text/javascript">
        function check() {
            var name = document.getElementById("name");;
            var riq = document.getElementById("riq");
            var songh = document.getElementById("songh");
            
            //非空
            if(name.value == '' && riq.value == '' && songh.value == '') {
                alert('请填写一个条件');
                return false;
            }
        }
    </script>
</body>
</html>

检索成功界面

<%@ 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>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<style>
    .a{
        margin-top: 20px;
    }
    .b{
        font-size: 20px;
         160px;
        color: white;
        background-color: greenyellow;
    }
    .tb, td {
        border: 1px solid black;
        font-size: 22px;
    }
</style>
</head>
<body>
    <div align="center">
        <h1 style="color: red;">课程信息列表</h1>
        <a href="index.jsp">返回主页</a>
        <table class="tb">
            <tr>
                <td>id</td>
                <td>商品名称</td>
                <td>生产厂家</td>
                <td>型号</td>
                <td>规格</td>
                <td>数量</td>
                <td>日期</td>
                <td>时间</td>
                <td>入库单位</td>
                <td>送货人</td>
            </tr>
            <!-- forEach遍历出adminBeans -->
            <c:forEach items="${courses}" var="item" varStatus="status">
                <tr>
                    <td>${item.id}</td>
                    <td><a>${item.name}</a></td>
                    <td>${item.shengc}</td>
                    <td>${item.xingh}</td>
                    <td>${item.guig}</td>
                    <td>${item.shul}</td>
                    <td><a>${item.riq}</a></td>
                    <td>${item.shij}</td>
                    <td>${item.ruk}</td>
                    <td><a>${item.songh}</a></td>
                </tr>
            </c:forEach>
        </table>
    </div>
</body>
</html>

数据库的增删该查要每个方法都连接上数据库

连接上数据库 每次的 类中的变量 都要准确同一 错一处就很难找出来 还会报错 ；