项目学习---Javaweb（超市订单管理系统）

知识点

MVC模型:
实现步骤:分为3级
1.M(Model) 持久层代码与数据库进行交互的代码(Mybatis-dao层)
2.C(Control) 控制层完成某项业务的具体操作过程(Controller层----Service层)
3.V(View) 视图层一般指用户看到的内容(页面)

项目目录

.filter //过滤器解决中文字符集乱码√
.util //数据库连接工具类√
.pojo //实体类√
.dao //数据操作类√-------M数据访问层
.servlet //servlet类√
service层：服务层√

1.数据库

2.filter下新建一个EncodingFilter用来解决中文字符集乱码

3.web.xml下进行对EncodingFilter相应的配置

4.在util下新建一个类用来处理对数据库的连接操作

5.在pojo下新建一个Provider实体类

pojo---provider

package com.baidou.pojo;

import java.util.Date;

/**
 * 供应商实体类
 */
public class Provider {
	
	private Integer id;   //id
	private String proCode; //供应商编码
	private String proName; //供应商名称
	private String proDesc; //供应商描述
	private String proContact; //供应商联系人
	private String proPhone; //供应商电话
	private String proAddress; //供应商地址
	private String proFax; //供应商传真
	private Integer createdBy; //创建者
	private Date creationDate; //创建时间
	private Integer modifyBy; //更新者
	private Date modifyDate;//更新时间
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public String getProCode() {
		return proCode;
	}
	public void setProCode(String proCode) {
		this.proCode = proCode;
	}
	public String getProName() {
		return proName;
	}
	public void setProName(String proName) {
		this.proName = proName;
	}
	public String getProDesc() {
		return proDesc;
	}
	public void setProDesc(String proDesc) {
		this.proDesc = proDesc;
	}
	public String getProContact() {
		return proContact;
	}
	public void setProContact(String proContact) {
		this.proContact = proContact;
	}
	public String getProPhone() {
		return proPhone;
	}
	public void setProPhone(String proPhone) {
		this.proPhone = proPhone;
	}
	public String getProAddress() {
		return proAddress;
	}
	public void setProAddress(String proAddress) {
		this.proAddress = proAddress;
	}
	public String getProFax() {
		return proFax;
	}
	public void setProFax(String proFax) {
		this.proFax = proFax;
	}
	public Integer getCreatedBy() {
		return createdBy;
	}
	public void setCreatedBy(Integer createdBy) {
		this.createdBy = createdBy;
	}
	public Date getCreationDate() {
		return creationDate;
	}
	public void setCreationDate(Date creationDate) {
		this.creationDate = creationDate;
	}
	public Integer getModifyBy() {
		return modifyBy;
	}
	public void setModifyBy(Integer modifyBy) {
		this.modifyBy = modifyBy;
	}
	public Date getModifyDate() {
		return modifyDate;
	}
	public void setModifyDate(Date modifyDate) {
		this.modifyDate = modifyDate;
	}
	
	
}

5.在dao下新建一个ProviderDao接口以及对应的方法实现类（使用接口类是为了规范开发）

dao---provider---ProviderDao

package com.baidou.dao.provider;

import com.baidou.pojo.Provider;

import java.sql.Connection;
import java.util.List;

public interface ProviderDao {

	//增加供应商
	public int add(Connection connection, Provider provider)throws Exception;

	// 通过供应商名称、编码获取供应商列表-模糊查询-providerList
	public List<Provider> getProviderList(Connection connection, String proName, String proCode)throws Exception;
	
	//通过proId删除Provider

	public int deleteProviderById(Connection connection, String delId)throws Exception;

	//通过proId获取Provider
	public Provider getProviderById(Connection connection, String id)throws Exception;
	
	//修改用户信息
	public int modify(Connection connection, Provider provider)throws Exception;
	
	
}

6.新建ProviderDaoImpl.java 实现ProviderDao接口，及未实现的方法

dao---provider---ProviderDaoimpl

package com.baidou.dao.provider;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

import com.baidou.dao.BaseDao;
import com.baidou.pojo.Provider;
import com.mysql.jdbc.StringUtils;

/**
 * Provider数据持久层
 */
public class ProviderDaoImpl implements ProviderDao {

	//添加供应商
	public int add(Connection connection, Provider provider)
			throws Exception {
		// TODO Auto-generated method stub
		PreparedStatement pstm = null;
		int flag = 0;
		if(null != connection){
			String sql = "insert into smbms_provider (proCode,proName,proDesc," +
					"proContact,proPhone,proAddress,proFax,createdBy,creationDate) " +
					"values(?,?,?,?,?,?,?,?,?)";
			Object[] params = {provider.getProCode(),provider.getProName(),provider.getProDesc(),
								provider.getProContact(),provider.getProPhone(),provider.getProAddress(),
								provider.getProFax(),provider.getCreatedBy(),provider.getCreationDate()};
			flag = BaseDao.execute(connection, pstm, sql, params);
			BaseDao.closeResource(null, pstm, null);
		}
		return flag;
	}

	//通过条件查询获取供应商列表
	public List<Provider> getProviderList(Connection connection, String proName,String proCode)
			throws Exception {
		// TODO Auto-generated method stub
		PreparedStatement pstm = null;
		ResultSet rs = null;
		List<Provider> providerList = new ArrayList<Provider>();
		if(connection != null){
			StringBuffer sql = new StringBuffer();
			sql.append("select * from smbms_provider where 1=1 ");
			List<Object> list = new ArrayList<Object>();
			if(!StringUtils.isNullOrEmpty(proName)){
				sql.append(" and proName like ?");
				list.add("%"+proName+"%");
			}
			if(!StringUtils.isNullOrEmpty(proCode)){
				sql.append(" and proCode like ?");
				list.add("%"+proCode+"%");
			}
			Object[] params = list.toArray();
			System.out.println("sql ----> " + sql.toString());
			rs = BaseDao.execute(connection, pstm, rs, sql.toString(), params);
			while(rs.next()){
				Provider _provider = new Provider();
				_provider.setId(rs.getInt("id"));
				_provider.setProCode(rs.getString("proCode"));
				_provider.setProName(rs.getString("proName"));
				_provider.setProDesc(rs.getString("proDesc"));
				_provider.setProContact(rs.getString("proContact"));
				_provider.setProPhone(rs.getString("proPhone"));
				_provider.setProAddress(rs.getString("proAddress"));
				_provider.setProFax(rs.getString("proFax"));
				_provider.setCreationDate(rs.getTimestamp("creationDate"));
				providerList.add(_provider);
			}
			BaseDao.closeResource(null, pstm, rs);
		}
		return providerList;
	}

	//删除供应商信息
	public int deleteProviderById(Connection connection, String delId)
			throws Exception {
		// TODO Auto-generated method stub
		PreparedStatement pstm = null;
		int flag = 0;
		if(null != connection){
			String sql = "delete from smbms_provider where id=?";
			Object[] params = {delId};
			flag = BaseDao.execute(connection, pstm, sql, params);
			BaseDao.closeResource(null, pstm, null);
		}
		return flag;
	}

	//通过id获取供应商
	public Provider getProviderById(Connection connection, String id)
			throws Exception {
		// TODO Auto-generated method stub
		Provider provider = null;
		PreparedStatement pstm = null;
		ResultSet rs = null;
		if(null != connection){
			String sql = "select * from smbms_provider where id=?";
			Object[] params = {id};
			rs = BaseDao.execute(connection, pstm, rs, sql, params);
			if(rs.next()){
				provider = new Provider();
				provider.setId(rs.getInt("id"));
				provider.setProCode(rs.getString("proCode"));
				provider.setProName(rs.getString("proName"));
				provider.setProDesc(rs.getString("proDesc"));
				provider.setProContact(rs.getString("proContact"));
				provider.setProPhone(rs.getString("proPhone"));
				provider.setProAddress(rs.getString("proAddress"));
				provider.setProFax(rs.getString("proFax"));
				provider.setCreatedBy(rs.getInt("createdBy"));
				provider.setCreationDate(rs.getTimestamp("creationDate"));
				provider.setModifyBy(rs.getInt("modifyBy"));
				provider.setModifyDate(rs.getTimestamp("modifyDate"));
			}
			BaseDao.closeResource(null, pstm, rs);
		}
		return provider;
	}

	//修改供应商信息
	public int modify(Connection connection, Provider provider)
			throws Exception {
		// TODO Auto-generated method stub
		int flag = 0;
		PreparedStatement pstm = null;
		if(null != connection){
			String sql = "update smbms_provider set proName=?,proDesc=?,proContact=?," +
					"proPhone=?,proAddress=?,proFax=?,modifyBy=?,modifyDate=? where id = ? ";
			Object[] params = {provider.getProName(),provider.getProDesc(),provider.getProContact(),provider.getProPhone(),provider.getProAddress(),
					provider.getProFax(),provider.getModifyBy(),provider.getModifyDate(),provider.getId()};
			flag = BaseDao.execute(connection, pstm, sql, params);
			BaseDao.closeResource(null, pstm, null);
		}
		return flag;
	}

}

7.在servlet下创建ProviderServlet用来实现对供应商登录的操作

package com.baidou.servlet.provider;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.alibaba.fastjson.JSONArray;
import com.baidou.pojo.Provider;
import com.baidou.pojo.User;
import com.baidou.service.provider.ProviderService;
import com.baidou.service.provider.ProviderServiceImpl;
import com.baidou.util.Constants;
import com.mysql.jdbc.StringUtils;

/**
 * 供应商Controller,实现servlet复用
 */
public class ProviderServlet extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        //通过路由调用相应的业务
        String method = request.getParameter("method");
        System.out.println("method--->" + method);

        if (method != null && method.equals("query")) {
            this.query(request, response);
        } else if (method != null && method.equals("add")) {
            this.add(request, response);
        } else if (method != null && method.equals("view")) {
            this.getProviderById(request, response, "providerview.jsp");
        } else if (method != null && method.equals("modify")) {
            this.getProviderById(request, response, "providermodify.jsp");
        } else if (method != null && method.equals("modifysave")) {
            this.modify(request, response);
        } else if (method != null && method.equals("delprovider")) {
            this.delProvider(request, response);
        }
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        this.doGet(request, response);
    }

    /**
     * 删除供应商信息
     *
     * @param request
     * @param response
     * @throws ServletException
     * @throws IOException
     */
    private void delProvider(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String id = request.getParameter("proid");
        HashMap<String, String> resultMap = new HashMap<String, String>();
        if (!StringUtils.isNullOrEmpty(id)) {
            ProviderService providerService = new ProviderServiceImpl();
            int flag = providerService.deleteProviderById(id);
            if (flag == 0) {//删除成功
                resultMap.put("delResult", "true");
            } else if (flag == -1) {//删除失败
                resultMap.put("delResult", "false");
            } else if (flag > 0) {//该供应商下有订单，不能删除，返回订单数
                resultMap.put("delResult", String.valueOf(flag));
            }
        } else {
            resultMap.put("delResult", "notexit");
        }
        //把resultMap转换成json对象输出
        response.setContentType("application/json");
        PrintWriter outPrintWriter = response.getWriter();
        outPrintWriter.write(JSONArray.toJSONString(resultMap));
        outPrintWriter.flush();
        outPrintWriter.close();
    }

    /**
     * 修改供应商信息
     *
     * @param request
     * @param response
     * @throws ServletException
     * @throws IOException
     */
    private void modify(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String proContact = request.getParameter("proContact");
        String proPhone = request.getParameter("proPhone");
        String proAddress = request.getParameter("proAddress");
        String proFax = request.getParameter("proFax");
        String proDesc = request.getParameter("proDesc");
        String id = request.getParameter("id");
        Provider provider = new Provider();
        provider.setId(Integer.valueOf(id));
        provider.setProContact(proContact);
        provider.setProPhone(proPhone);
        provider.setProFax(proFax);
        provider.setProAddress(proAddress);
        provider.setProDesc(proDesc);
        provider.setModifyBy(((User) request.getSession().getAttribute(Constants.USER_SESSION)).getId());
        provider.setModifyDate(new Date());
        boolean flag = false;
        ProviderService providerService = new ProviderServiceImpl();
        flag = providerService.modify(provider);
        if (flag) {
            response.sendRedirect(request.getContextPath() + "/jsp/provider.do?method=query");
        } else {
            request.getRequestDispatcher("providermodify.jsp").forward(request, response);
        }
    }

    /**
     * 通过id获取供应商
     *
     * @param request
     * @param response
     * @param url
     * @throws ServletException
     * @throws IOException
     */
    private void getProviderById(HttpServletRequest request, HttpServletResponse response, String url)
            throws ServletException, IOException {
        String id = request.getParameter("proid");
        System.out.println("id-->" + id);
        Provider provider = null;
        if (!StringUtils.isNullOrEmpty(id)) {
            ProviderService providerService = new ProviderServiceImpl();
            provider = providerService.getProviderById(id);
            request.setAttribute("provider", provider);
            request.getRequestDispatcher(url).forward(request, response);
        }
    }

    /**
     * 添加供应商
     *
     * @param request
     * @param response
     * @throws ServletException
     * @throws IOException
     */
    private void add(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        boolean flag = false;
        String proCode = request.getParameter("proCode");
        String proName = request.getParameter("proName");
        String proContact = request.getParameter("proContact");
        String proPhone = request.getParameter("proPhone");
        String proAddress = request.getParameter("proAddress");
        String proFax = request.getParameter("proFax");
        String proDesc = request.getParameter("proDesc");

        Provider provider = new Provider();
        provider.setProCode(proCode);
        provider.setProName(proName);
        provider.setProContact(proContact);
        provider.setProPhone(proPhone);
        provider.setProFax(proFax);
        provider.setProAddress(proAddress);
        provider.setProDesc(proDesc);
        provider.setCreatedBy(((User) request.getSession().getAttribute(Constants.USER_SESSION)).getId());
        provider.setCreationDate(new Date());

        ProviderService providerService = new ProviderServiceImpl();
        flag = providerService.add(provider);
        if (flag) {
            response.sendRedirect(request.getContextPath() + "/jsp/provider.do?method=query");
        } else {
            request.getRequestDispatcher("provideradd.jsp").forward(request, response);
        }
    }

    /**
     * 获取供应商列表
     *
     * @param request
     * @param response
     * @throws ServletException
     * @throws IOException
     */
    private void query(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String queryProName = request.getParameter("queryProName");
        String queryProCode = request.getParameter("queryProCode");
        if (StringUtils.isNullOrEmpty(queryProName)) {
            queryProName = "";
        }
        if (StringUtils.isNullOrEmpty(queryProCode)) {
            queryProCode = "";
        }
        List<Provider> providerList = new ArrayList<Provider>();
        ProviderService providerService = new ProviderServiceImpl();
        providerList = providerService.getProviderList(queryProName, queryProCode);
        request.setAttribute("providerList", providerList);
        request.setAttribute("queryProName", queryProName);
        request.setAttribute("queryProCode", queryProCode);
        request.getRequestDispatcher("providerlist.jsp").forward(request, response);
    }

}

有两点要注意的地方：

一：getParameter与getAttribute两者的区别

request.setAttribute("xiaoxi", "欢迎用户"+name);//向request域中放置信息（键值对的形式）名字为xiaoxi 内容为"欢迎用户"+name

request.getAttribute("xiaoxi");//得到request域中放置名字为xiaoxi的信息

request.getParameter("name");//得到request域的参数信息（得到jsp页面传过来的参数）

getAttribute表示从request范围取得设置的属性，必须要先setAttribute设置属性，才能通过getAttribute来取得，设置与取得的为Object对象类型。

getParameter表示接收参数，参数为页面提交的参数，包括：表单提交的参数、URL重写（就是xxx?id=1中的id）传的参数等，因此这个并没有设置参数的方法（没有setParameter），而且接收参数返回的不是Object，而是String类型

二：转发与重定向的区别

（1）.重定向的执行过程：Web服务器向浏览器发送一个http响应--》浏览器接受此响应后再发送一个新的http请求到服务器--》服务器根据此请求寻找资源并发送给浏览器。它可以重定向到任意URL，不能共享request范围内的数据。
（2）.重定向是在客户端发挥作用，通过新的地址实现页面转向。
（3）.重定向是通过浏览器重新请求地址，在地址栏中可以显示转向后的地址。
（4）.转发过程：Web服务器调用内部方法在容器内部完成请求和转发动作--》将目标资源发送给浏览器，它只能在同一个Web应用中使用，可以共享request范围内的数据。
（5）.转发是在服务器端发挥作用，通过forward()方法将提交信息在多个页面间进行传递。
（6）.转发是在服务器内部控制权的转移，客户端浏览器的地址栏不会显示出转向后的地址。
————————————————

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原文链接：https://blog.csdn.net/qq_23994787/article/details/73612870

8.配置servlet在web.xml

9.新建jsp页面

webapp---jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@include file="/jsp/common/head.jsp"%>

<div class="right">
        <div class="location">
            <strong>你现在所在的位置是:</strong>
            <span>供应商管理页面 >> 供应商添加页面</span>
        </div>
        <div class="providerAdd">
           <form id="providerForm" name="providerForm" method="post" action="${pageContext.request.contextPath }/jsp/provider.do">
			<input type="hidden" name="method" value="add">
                <!--div的class 为error是验证错误，ok是验证成功-->
                <div class="">
                    <label for="proCode">供应商编码：</label>
                    <input type="text" name="proCode" id="proCode" value=""> 
					<!-- 放置提示信息 -->
					<font color="red"></font>
                </div>
                <div>
                    <label for="proName">供应商名称：</label>
                   <input type="text" name="proName" id="proName" value=""> 
					<font color="red"></font>
                </div>
                <div>
                    <label for="proContact">联系人：</label>
                    <input type="text" name="proContact" id="proContact" value=""> 
					<font color="red"></font>

                </div>
                <div>
                    <label for="proPhone">联系电话：</label>
                    <input type="text" name="proPhone" id="proPhone" value=""> 
					<font color="red"></font>
                </div>
                <div>
                    <label for="proAddress">联系地址：</label>
                    <input type="text" name="proAddress" id="proAddress" value=""> 
                </div>
                <div>
                    <label for="proFax">传真：</label>
                    <input type="text" name="proFax" id="proFax" value=""> 
                </div>
                <div>
                    <label for="proDesc">描述：</label>
                    <input type="text" name="proDesc" id="proDesc" value=""> 
                </div>
                <div class="providerAddBtn">
                    <input type="button" name="add" id="add" value="保存">
					<input type="button" id="back" name="back" value="返回" >
                </div>
            </form>
     </div>
</div>
</section>
<%@include file="/jsp/common/foot.jsp" %>
<script type="text/javascript" src="${pageContext.request.contextPath }/js/provideradd.js"></script>