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;   //idprivate 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-providerListpublic List<Provider> getProviderList(Connection connection, String proName, String proCode)throws Exception;//通过proId删除Providerpublic int deleteProviderById(Connection connection, String delId)throws Exception;//通过proId获取Providerpublic 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 stubPreparedStatement 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 stubPreparedStatement 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 stubPreparedStatement 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 stubProvider 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 stubint 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>