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Devmax。