新人有人求问，百度了还是不明白，希望大佬解答下。

sinat_21364779 2022-04-08 01:20:30

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>首页</title>
    <script src="js/jquery-3.3.1.min.js"></script>
    <script>
        //入口函数
        $(function () {
            //获取province的id
            var province = $("#province");

            //json
            $.get("provinceServlet",{},function (data) {
                $(data).each(function () {
                    var option = "<option name='" + this.id + "'>"+ this.name +"</option>";
                    province.append(option);
                });
            });
        });
    </script>
</head>
<body>
    <select id="province">
        <option>---请选择省份---</option>
    </select>
</body>
</html>

package cn.max.web.servlet;

import cn.max.domain.Province;
import cn.max.service.ProvinceService;
import cn.max.service.impl.ProvinceServiceImpl;
import com.fasterxml.jackson.databind.ObjectMapper;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;

@WebServlet("/provinceServlet")
public class ProvinceServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        //1.调用service查询数据库
        ProvinceService service = new ProvinceServiceImpl();
        List<Province> list = service.findAll();

        //2.序列化list转为json
        ObjectMapper mapper = new ObjectMapper();
        String json = mapper.writeValueAsString(list);

        //System.out.println(json);
        ///[{"id":1,"name":"北京"},{"id":2,"name":"上海"},{"id":3,"name":"广州"},{"id":4,"name":"陕西"}]

        //3.响应结果
        response.setContentType("application/json;charset=utf-8");
        response.getWriter().write(json);
    }

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

$.get("provinceServlet",{},function (data) {
$(data).each(function () {
var option = "<option name='" + this.id + "'>"+ this.name +"</option>";
province.append(option);
});
});

为啥this.id 可以获取值，用data.id获取不到值，data不是接收了servlet的返回结果吗，this这里指向的又是哪里，还是我理解错。T.T

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