Ajax三级联动效果 Ajax实现三级联动效果

时间:2021-10-04 想到的名字都被人用了人气:0

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一、导入数据表和gson.jar

该表包括了中国所有的省、市、县、区，它们之间通过parentid关联。

二、后端代码

由于每一级的数据都是根据上一级的id查询而来，逻辑十分相似，故我们只需要一个接口就可以完成三级甚至更多级的联动，在这个案例中我们的核心查询就是select * from area where parentid=#{pid}

entity

package com.codeXie.entity;

import java.io.Serializable;

public class Area implements Serializable {
    private String areaid;
    private String areaname;
    private String parentid;
    private Integer arealevel;
    private Integer status;

    public Area() {
    }

    public Area(String areaid, String areaname, String parentid, Integer arealevel, Integer status) {
        this.areaid = areaid;
        this.areaname = areaname;
        this.parentid = parentid;
        this.arealevel = arealevel;
        this.status = status;
    }
    .......省略了对各属性的set、get
}

mapper

public interface AreaMapper {
    @Select("select * from area where parentid=#{pid}")
    List<Area> selectMore(Integer pid);
}

service

public interface AreaService {
    List<Area> findCity(int pid);
}

servlet

@WebServlet("/AreaServlet")
public class AreaServlet extends HttpServlet {
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setCharacterEncoding("utf-8");
        resp.setContentType("text/html;charset=utf-8");
        String pid = req.getParameter("pid");
        AreaServiceImpl service = new AreaServiceImpl();
        List<Area> areas = service.findCity(Integer.parseInt(pid));
        String json = new Gson().toJson(areas);
        resp.getWriter().print(json);
    }
}

三、前端代码

 <script src="js/jquery.js"></script>
    <script>
        function produceOption(id,list){
            console.log(list)
            $(id).empty()
            $(list).each((index,item)=>{
                $(id).append("<option value="+item.areaid+">"+item.areaname+"</option>")
            })
            
        }
        $(()=>{
            $.ajax({
                url:"AreaServlet",
                method:"post",
                data:{pid:0},
                dataType:"json",
                success: function(res) {
                   produceOption("#proviance",res)
                   $("#proviance").prepend("<option selected='selected'>请选择省份</option>")
                }
            })
            $("#proviance").change(function(){
                var pid = $(this).prop("value")
                $.ajax({
                url:"AreaServlet",
                method:"post",
                data:{pid:pid},
                dataType:"json",
                success: function(res) {
                   produceOption("#city",res)
                   $("#city").prepend("<option selected='selected'>请选择城市</option>")
                }
            })
        })
        $("#city").on("change",function(){
            var pid = $(this).prop("value")
                $.ajax({
                url:"AreaServlet",
                method:"post",
                data:{pid:pid},
                dataType:"json",
                success: function(res) {
                   produceOption("#country",res)
                   
                }
            })
        })
    })
    </script>
</head>
<body>
    <h2>三级联动</h2>
    <hr/>
    <select name="pro" id="proviance">
        <option>选择省份</option>
    </select>
    <select name="city" id="city">
        <option>选择城市</option>
    </select>
    <select name="country" id="country">
        <option>请选择区域</option>
    </select>
</body>
</html>

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