文章目录
jsp页面（灵活运用传参的数据，通过method使servlet分辨出要执行的方法）servlet（即服务接口）状态码的枚举类省市县对象实体类
jsp页面（灵活运用传参的数据，通过method使servlet分辨出要执行的方法）
<html>
<head>
<title>省市三级级联
</title
>
<script type
="text/javascript" src
="<%=request.getContextPath()%>/js/jquery-3.4.1.min.js"></script
>
<script>
$
(function
() {
$
.post("/day6/area", {"method": "getProv"}, function
(data
) {
if (data
.returnCode
== 200) {
$
.each(data
.returnData
, function
(i
, d
) {
var p
= "<option value='" + d
.areaId
+ "'>" + d
.areaName
+ "</option>";
$
("#prov").append(p
);
});
}
}, "json");
$
("#prov").change(function
() {
$
("#city").html("<option>--------请选择--------</option>");
$
("#coun").html("<option>--------请选择--------</option>");
var provCode
= $
(this).val();
$
.post("/day6/area", {"method": "getCity", "provCode": provCode
}, function
(data
) {
if (data
.returnCode
== 200) {
$
.each(data
.returnData
, function
(i
, d
) {
var c
= "<option value='" + d
.areaId
+ "'>" + d
.areaName
+ "</option>";
$
("#city").append(c
);
});
}
}, "json");
});
$
("#city").change(function
() {
$
("#coun").html("<option>--------请选择--------</option>");
var cityCode
= $
(this).val();
console
.log(cityCode
);
$
.post("/day6/area", {"method": "getCoun", "cityCode": cityCode
}, function
(data
) {
if (data
.returnCode
== 200) {
$
.each(data
.returnData
, function
(i
, d
) {
var coun
= "<option value='" + d
.areaId
+ "'>" + d
.areaName
+ "</option>";
$
("#coun").append(coun
);
});
}
}, "json");
});
})
</script
>
</head
>
<body>
<h3>省市级联
</h3
>
<select id
="prov">
<option>--------请选择
--------</option
>
</select
>
<select id
="city">
<option>--------请选择
--------</option
>
</select
>
<select id
="coun">
<option>--------请选择
--------</option
>
</select
>
</body
>
</html
>
servlet（即服务接口）
public class AreaServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req
, HttpServletResponse resp
) throws ServletException
, IOException
{
doPost(req
, resp
);
}
@Override
protected void doPost(HttpServletRequest req
, HttpServletResponse resp
) throws ServletException
, IOException
{
req
.setCharacterEncoding("utf-8");
resp
.setContentType("text/html;charset=utf-8");
PrintWriter pw
= resp
.getWriter();
Map
<String, Object> map
= new HashMap<>();
List
<Area> areas
= null
;
String method
= req
.getParameter("method");
if ("getProv".equals(method
)) {
areas
= getProv(req
, resp
);
} else if ("getCity".equals(method
)) {
areas
= getCity(req
, resp
);
} else if ("getCoun".equals(method
)){
areas
= getCoun(req
, resp
);
}
if (areas
.size() == 0) {
map
.put("returnCode", ReturnCode
.ERROR
.getCode());
map
.put("returnMsg", ReturnCode
.ERROR
.getMsg());
} else {
map
.put("returnCode", ReturnCode
.SUCCESS
.getCode());
map
.put("returnMsg", ReturnCode
.SUCCESS
.getMsg());
}
map
.put("returnData", areas
);
String prov
= JSON
.toJSONString(map
);
pw
.print(prov
);
pw
.flush();
pw
.close();
}
private List
<Area> getProv(HttpServletRequest req
, HttpServletResponse resp
) throws ServletException
, IOException
{
try {
return new AreaServiceImpl().queryProv();
} catch (SQLException e
) {
e
.printStackTrace();
}
return null
;
}
private List
<Area> getCity(HttpServletRequest req
, HttpServletResponse resp
) throws ServletException
, IOException
{
String provCode
= req
.getParameter("provCode");
try {
return new AreaServiceImpl().queryCity(provCode
);
} catch (SQLException e
) {
e
.printStackTrace();
}
return null
;
}
private List
<Area> getCoun(HttpServletRequest req
, HttpServletResponse resp
) throws ServletException
, IOException
{
String cityCode
= req
.getParameter("cityCode");
try {
return new AreaServiceImpl().queryCoun(cityCode
);
} catch (SQLException e
) {
e
.printStackTrace();
}
return null
;
}
}
状态码的枚举类
public enum ReturnCode
{
SUCCESS("200", "成功"),
ERROR("404", "失败");
private String code
;
private String msg
;
private ReturnCode(String code
, String msg
) {
this.code
= code
;
this.msg
= msg
;
}
public String
getCode() {
return code
;
}
public String
getMsg() {
return msg
;
}
}
省市县对象实体类
public class Area {
private String areaId
;
private String areaName
;
@Override
public String
toString() {
return "Area{" +
"areaId='" + areaId
+ '\'' +
", areaName='" + areaName
+ '\'' +
'}';
}
public String
getAreaId() {
return areaId
;
}
public void setAreaId(String areaId
) {
this.areaId
= areaId
;
}
public String
getAreaName() {
return areaName
;
}
public void setAreaName(String areaName
) {
this.areaName
= areaName
;
}
public Area(String areaId
, String areaName
) {
this.areaId
= areaId
;
this.areaName
= areaName
;
}
}
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