家庭记账本（十）

5.Web层Servlet层

Servlet创建方式：项目名右键new--Servlet,使用@WebServlet注解，省去配置web.xml的时间

1 package com.wang.web;
  2 
  3 import java.io.IOException;
  4 import java.math.BigDecimal;
  5 import java.util.List;
  6 
  7 import javax.servlet.ServletException;
  8 import javax.servlet.annotation.WebServlet;
  9 import javax.servlet.http.HttpServlet;
 10 import javax.servlet.http.HttpServletRequest;
 11 import javax.servlet.http.HttpServletResponse;
 12 
 13 import com.wang.pojo.HomeCost;
 14 import com.wang.service.HomeCostService;
 15 import com.wang.utils.WebUtils;
 16 
 17 /**
 18  * 访问地址url:localhost:8080/homeCost/manager/homeCostServlet
 19  * Servlet implementation class HomeCostServlet
 20  */
 21 @WebServlet("/manager/homeCostServlet")
 22 public class HomeCostServlet extends HttpServlet {
 23     private static final long serialVersionUID = 1L;
 24     private HomeCostService homeCostService = new HomeCostService();
 25     
 26     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 27         doPost(request, response);
 28     }
 29 
 30     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 31         String action = request.getParameter("action");
 32         if("add".equals(action)) {
 33             add(request, response);
 34         }else if("delete".equals(action)) {
 35             delete(request, response);
 36         }else if("update".equals(action)) {
 37             update(request, response);
 38         }else if("list".equals(action)) {
 39             list(request, response);
 40         }else if("getHomeCostById".equals(action)) {
 41             getHomeCostById(request, response);
 42         }else if("query".equals(action)) {
 43             query(request, response);
 44         }
 45     }
 46     
 47     //添加消费记录
 48     protected void add(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 49         //获取网页提交的参数
 50         String name = request.getParameter("name");
 51         BigDecimal money = WebUtils.bigdecimal(request.getParameter("money"), new BigDecimal(0.00));
 52         //封装成类对象
 53         HomeCost homeCost = new HomeCost(name,money);
 54         //执行添加操作，返回1,添加成功，反之失败
 55         if(homeCostService.add(homeCost) == 1) {
 56             //页面重定向
 57             response.sendRedirect(request.getContextPath()+"/manager/homeCostServlet?action=list");
 58         }else {
 59             //请求转发
 60             request.setAttribute("msg", "添加失败，联系管理员");
 61             request.setAttribute("homeCost", homeCost);
 62             request.getRequestDispatcher("/cost_edit.jsp").forward(request, response);
 63         }
 64     }
 65     //删除消费记录
 66     protected void delete(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 67         //获取id
 68         int id  = WebUtils.parseInt(request.getParameter("id"), 0);
 69         //执行删除操作，返回1,删除成功，反之失败
 70         if (homeCostService.delete(id) == 1) {
 71             //页面重定向
 72             response.sendRedirect(request.getContextPath()+"/manager/homeCostServlet?action=list");
 73         }else {
 74             //请求转发
 75             request.setAttribute("msg", "删除失败，联系管理员");
 76             request.getRequestDispatcher("/manager/homeCostServlet?action=list").forward(request, response);
 77         }
 78         
 79     }
 80     //修改消费记录
 81     protected void update(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 82         //获取参数
 83         int id  = WebUtils.parseInt(request.getParameter("id"), 0);
 84         String name = request.getParameter("name");
 85         BigDecimal money = WebUtils.bigdecimal(request.getParameter("money"), new BigDecimal(0.00));
 86         String date = request.getParameter("date");
 87         //封装
 88         HomeCost homeCost = new HomeCost(id,name,money,date);
 89         //执行删除操作，返回1,修改成功，反之失败
 90         if(homeCostService.update(homeCost) == 1) {
 91             response.sendRedirect(request.getContextPath()+"/manager/homeCostServlet?action=list");
 92         }else {
 93             request.setAttribute("msg", "修改失败，联系管理员");
 94             request.setAttribute("homeCost", homeCost);
 95             request.getRequestDispatcher("/cost_edit.jsp").forward(request, response);
 96         }
 97     }
 98     //查询全部消费记录
 99     protected void list(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
100         List<HomeCost> homeCost = homeCostService.list();
101         request.setAttribute("homeCost", homeCost);
102         request.getRequestDispatcher("/manager.jsp").forward(request, response);
103         
104     }
105     //通过id查询该条消费记录
106     private void getHomeCostById(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
107         int id  = WebUtils.parseInt(request.getParameter("id"), 0);
108         HomeCost homeCost = homeCostService.getHomeCostById(id);
109         request.setAttribute("homeCost", homeCost);
110         request.getRequestDispatcher("/cost_edit.jsp").forward(request, response);
111     }
112     //通过关键词查询
113     protected void query(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
114         String keyword=request.getParameter("keyword");
115         List<HomeCost> homeCost = homeCostService.query(keyword);
116         request.setAttribute("homeCost", homeCost);
117         request.getRequestDispatcher("/query.jsp").forward(request, response);
118         
119     }
120 
121 
122 }

HomeCostServlet.java

6.工具类

1 package com.wang.utils;
 2 
 3 import java.math.BigDecimal;
 4 
 5 public class WebUtils {
 6     
 7     //该类为工具类，封装常用的函数，catch类型转换异常，保障程序健壮性
 8     
 9     
10     /**
11      * String转BigDecimal发生异常返回默认值
12      * @param str  字符串
13      * @param defaultValue 默认值
14      * @return BigDecimal值
15      */
16     public static BigDecimal bigdecimal(String str,BigDecimal defaultValue) {
17         try {
18             return new BigDecimal(str);
19         } catch (Exception e) {
20             //e.printStackTrace();
21         }
22         return defaultValue;
23     }
24     
25     /**
26      * 字符串转int
27      * @param string 被转换的字符串
28      * @param defaultValue 默认值
29      * @return int
30      */
31     public static int parseInt(String string,int defaultValue){
32         try {
33             return Integer.parseInt(string);
34         } catch (NumberFormatException e) {
35             //e.printStackTrace();
36         }
37         return defaultValue;
38     }
39     
40 
41 }

WebUtils.java