• 项目实战：修改水果库存系统特定库存记录

    1、在edit.html修改库存页面添加点击事件

    1. html>
    2. <html lang="en">
    3. <head>
    4.     <meta charset="UTF-8">
    5.     <title>Titletitle>
    6.     <link rel="stylesheet" href="style/index.css">
    7.     <script src="script/axios.min.js">script>
    8.     <script src="script/edit.js">script>
    9.     <script src="script/common.js">script>
    10. head>
    11. <body>
    12. <div id="div0">
    13.     <div id="div_title">
    14.         <p>编辑水果库存信息p>
    15.     div>
    16.     <div id="div_fruit_table">
    17.         <input type="hidden" id="fid" value="0"/>
    18.         <table id="fruit_tbl">
    19.             <tr>
    20.                 <th class="w25">名称:th>
    21.                 <td><input type="text" id="fname"/>td>
    22.             tr>
    23.             <tr>
    24.                 <th class="w25">单价:th>
    25.                 <td><input type="text" name="price" id="price"/> td>
    26.             tr>
    27.             <tr>
    28.                 <th class="w25">库存:th>
    29.                 <td><input type="text" name="fcount" id="fcount"/> td>
    30.             tr>
    31.             <tr>
    32.                 <th class="w25">备注:th>
    33.                 <td><input type="text" name="remark" id="remark"/> td>
    34.             tr>
    35.             <tr>
    36.                 <th colspan="2">
    37.                     <input type="button" value="修改" onclick="update()"/>
    38.                     <input type="button" value="取消"/>
    39.                 th>
    40.             tr>
    41.         table>
    42.     div>
    43. div>
    44. body>
    45. html>

    2、在edit.js中添加update = function ( ) { } 功能

    2.1、common.js

    1. function $(key){
    2.     if(key){
    3.         if(key.startsWith("#")){
    4.             key = key.substring(1)
    5.             return document.getElementById(key)
    6.         }else{
    7.             let nodeList = document.getElementsByName(key)
    8.             return Array.from(nodeList)
    9.         }
    10.     }
    11. }

    2.2、edit.js 

    1. let queryString = window.location.search.substring(1)
    2. if(queryString){
    3.     var fid = queryString.split("=")[1]
    4.  
    5.     window.onload=function(){
    6.         loadFruit(fid)
    7.     }
    8.  
    9.     loadFruit = function(fid){
    10.         axios({
    11.             method:'get',
    12.             url:'edit',
    13.             params:{
    14.                 fid:fid
    15.             }
    16.         }).then(response=>{
    17.             debugger
    18.             let fruit = response.data.data
    19.             $("#fid").value=fruit.fid
    20.             $("#fname").value=fruit.fname
    21.             $("#price").value=fruit.price
    22.             $("#fcount").value=fruit.fcount
    23.             $("#remark").value=fruit.remark
    24.         })
    25.     }
    26.  
    27.     update=function(){
    28.         let fid = $("#fid").value
    29.         let fname = $("#fname").value
    30.         let price = $("#price").value
    31.         let fcount = $("#fcount").value
    32.         let remark = $("#remark").value
    33.         axios({
    34.             method:'post',
    35.             url:"update",
    36.             data:{
    37.                 fid:fid,
    38.                 fname:fname,
    39.                 price:price,
    40.                 fcount:fcount,
    41.                 remark:remark
    42.             }
    43.         }).then(response=>{
    44.             if(response.data.flag){
    45.                 window.location.href="index.html"
    46.             }
    47.         })
    48.     }
    49. }

    3、封装读取json字符串方法创建RequestUtil工具类

    1. package com.csdn.fruit.util;
    2. import jakarta.servlet.ServletRequest;
    3. import java.io.BufferedReader;
    4. import java.io.IOException;
    5. public class RequestUtil {
    6.     public static Object readObject(ServletRequest request, Class clazz) throws IOException {
    7.         BufferedReader br = request.getReader();
    8.         StringBuilder stringBuilder = new StringBuilder();
    9.         String str = null;
    10.         while ((str = br.readLine()) != null) {
    11.             stringBuilder.append(str);
    12.         }
    13.         str = stringBuilder.toString();
    14.         return GsonUtil.fromJson(str, clazz);
    15.     }
    16. }

    4、修改FruitDaoImpl类中的updateFruit方法中sql语句

    • 因为之前写的是只能通过 fname 修改 fcount
    • 现在想要通过 fid 可以修改所有的属性值，所以需要修改sql语句
    1. package com.csdn.fruit.dao.impl;
    2. import com.csdn.fruit.dao.FruitDao;
    3. import com.csdn.fruit.pojo.Fruit;
    4. import com.csdn.mymvc.dao.BaseDao;
    5. import java.util.List;
    6. public class FruitDaoImpl extends BaseDao implements FruitDao {
    7.     @Override
    8.     public void addFruit(Fruit fruit) {
    9.         String sql = "insert into t_fruit values (0,?,?,?,?)";
    10.         super.executeUpdate(sql, fruit.getFname(), fruit.getPrice(), fruit.getFcount(), fruit.getRemark());
    11.     }
    12.     @Override
    13.     public void delFruit(String fname) {
    14.         String sql = "delete from t_fruit where fname=?";
    15.         super.executeUpdate(sql, fname);
    16.     }
    17.     //通过 fid 可以修改所有的属性值
    18.     @Override
    19.     public void updateFruit(Fruit fruit) {
    20.         String sql = "update  t_fruit set fname=?,price=?,fcount=?,remark=? where fid = ?";
    21.         super.executeUpdate(sql, fruit.getFname(), fruit.getPrice(), fruit.getFcount(), fruit.getRemark(), fruit.getFid());
    22.     }
    23.     @Override
    24.     public List getFruitList() {
    25.         return super.executeQuery("select * from t_fruit");
    26.     }
    27.     @Override
    28.     public Fruit getFruitByFname(String fname) {
    29.         return load("select * from t_fruit where fname = ?", fname);
    30.     }
    31.     @Override
    32.     public Fruit getFruitByFid(Integer fid) {
    33.         return load("select * from t_fruit where fid=?", fid);
    34.     }
    35. }

    5、编写Controller层UpdateServlet

    1. package com.csdn.fruit.servlet;
    2. import com.csdn.fruit.dao.FruitDao;
    3. import com.csdn.fruit.dao.impl.FruitDaoImpl;
    4. import com.csdn.fruit.dto.Result;
    5. import com.csdn.fruit.pojo.Fruit;
    6. import com.csdn.fruit.util.RequestUtil;
    7. import com.csdn.fruit.util.ResponseUtil;
    8. import jakarta.servlet.ServletException;
    9. import jakarta.servlet.annotation.WebServlet;
    10. import jakarta.servlet.http.HttpServlet;
    11. import jakarta.servlet.http.HttpServletRequest;
    12. import jakarta.servlet.http.HttpServletResponse;
    13. import java.io.IOException;
    14. @WebServlet("/update")
    15. public class UpdateServlet extends HttpServlet {
    16.     private FruitDao fruitDao = new FruitDaoImpl();
    17.     @Override
    18.     protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    19.         Fruit fruit = (Fruit) RequestUtil.readObject(req, Fruit.class);
    20.         fruitDao.updateFruit(fruit);
    21.         ResponseUtil.print(resp, Result.OK());
    22.     }
    23. }

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  • 原文地址：https://blog.csdn.net/m0_65152767/article/details/134207337