Ajax实现三级联动效果_Ajax

本文实例为大家分享了ajax实现三级联动效果的具体代码，供大家参考，具体内容如下

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>

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持代码网。