1、前端编辑页面加载水果库存信息逻辑edit.js

let queryString = window.location.search.substring(1)
if(queryString){var fid = queryString.split("=")[1]window.onload=function(){loadFruit(fid)}loadFruit = function(fid){axios({method:'get',url:'edit',params:{fid:fid}}).then(response=>{let fruit = response.data.data$("#fid").value=fruit.fid$("#fname").value=fruit.fname$("#price").value=fruit.price$("#fcount").value=fruit.fcount$("#remark").value=fruit.remark})}/*    update=function(){let fid = $("#fid").valuelet fname = $("#fname").valuelet price = $("#price").valuelet fcount = $("#fcount").valuelet remark = $("#remark").valueaxios({method:'post',url:"update",data:{fid:fid,fname:fname,price:price,fcount:fcount,remark:remark}}).then(response=>{if(response.data.flag){window.location.href="index.html"}})}*/
}

2、 在FruitDao接口中添加通过id查询数据的方法

package com.csdn.fruit.dao;
import com.csdn.fruit.pojo.Fruit;
import java.util.List;
//dao ：Data Access Object 数据访问对象
//接口设计
public interface FruitDao {void addFruit(Fruit fruit);void delFruit(String fname);void updateFruit(Fruit fruit);List<Fruit> getFruitList();Fruit getFruitByFname(String fname);Fruit getFruitByFid(Integer fid);
}

3、在FruitDaoImpl实现类中实现getFruitByFid()方法

package com.csdn.fruit.dao.impl;
import com.csdn.fruit.dao.FruitDao;
import com.csdn.fruit.pojo.Fruit;
import com.csdn.mymvc.dao.BaseDao;
import java.util.List;
public class FruitDaoImpl extends BaseDao<Fruit> implements FruitDao {@Overridepublic void addFruit(Fruit fruit) {String sql = "insert into t_fruit values (0,?,?,?,?)";super.executeUpdate(sql, fruit.getFname(), fruit.getPrice(), fruit.getFcount(), fruit.getRemark());}@Overridepublic void delFruit(String fname) {String sql = "delete from t_fruit where fname=?";super.executeUpdate(sql, fname);}@Overridepublic void updateFruit(Fruit fruit) {String sql = "update  t_fruit set fcount=? where fname = ?";super.executeUpdate(sql, fruit.getFcount(), fruit.getFname());}@Overridepublic List<Fruit> getFruitList() {return super.executeQuery("select * from t_fruit");}@Overridepublic Fruit getFruitByFname(String fname) {return load("select * from t_fruit where fname = ?", fname);}@Overridepublic Fruit getFruitByFid(Integer fid) {return load("select * from t_fruit where fid=?", fid);}
}

4、编写EditServlet类实现前后端数据交互

package com.csdn.fruit.servlet;
import com.csdn.fruit.dao.FruitDao;
import com.csdn.fruit.dao.impl.FruitDaoImpl;
import com.csdn.fruit.dto.Result;
import com.csdn.fruit.pojo.Fruit;
import com.csdn.fruit.util.ResponseUtil;
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import java.io.IOException;
@WebServlet("/edit")
public class EditServlet extends HttpServlet {FruitDao fruitDao = new FruitDaoImpl();@Overrideprotected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {Integer fid = Integer.parseInt(req.getParameter("fid"));Fruit fruit = fruitDao.getFruitByFid(fid);ResponseUtil.print(resp, Result.OK(fruit));}
}

5、用到的工具类

5.1、ResponseUtil工具类

package com.csdn.fruit.util;
import com.csdn.fruit.dto.Result;
import jakarta.servlet.ServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
public class ResponseUtil {public static void print(ServletResponse response, Result result) throws IOException {response.setCharacterEncoding("UTF-8");response.setContentType("application/json;charset=utf-8");PrintWriter out = response.getWriter();out.println(GsonUtil.toJson(result));out.flush();}
}

5.2、GsonUtil工具类

package com.csdn.fruit.util;
import com.google.gson.Gson;
public class GsonUtil {public static String toJson(Object obj) {//java object ->  java json stringGson gson = new Gson();return gson.toJson(obj);}
}