jdbc工具类
public class JdbcUtils {
?
?public static BasicDataSource bs=null;
?
????????static{
?????????Properties p = new Properties();
?????????try {
p.load(JdbcUtils.class.getClassLoader().getResourceAsStream("properties/MysqlConfig.properties"));
bs= new BasicDataSource();
???bs.setUsername(p.getProperty("username"));
???bs.setPassword(p.getProperty("password"));
???bs.setUrl(p.getProperty("url"));
???bs.setDriverClassName(p.getProperty("className"));
???bs.setMaxActive(Integer.parseInt(p.getProperty("MaxActive")));
???bs.setInitialSize(Integer.parseInt(p.getProperty("initSize")));
???bs.setMaxWait(Long.parseLong(p.getProperty("maxWait")));
} catch (Exception e) {
e.printStackTrace();
System.out.println("文件加载失败");
}
????????
????????}
????????
??????public static DataSource ?getDataSource(){
???????????????
??????????return bs;
??????
??????}
????????
????????
}
数据库配置文件：
username=root
password=123456
MaxActive=5
url=jdbc:mysql:///city
className=com.mysql.jdbc.Driver
maxWait=5000
initSize=3
实体类
public class Os_district {
private int id;
private String name;
private int level;
private int upid;
public Os_district() {
super();
// TODO Auto-generated constructor stub
}
public Os_district(int id, String name, int level, int upid) {
super();
this.id = id;
this.name = name;
this.level = level;
this.upid = upid;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getLevel() {
return level;
}
public void setLevel(int level) {
this.level = level;
}
public int getUpid() {
return upid;
}
public void setUpid(int upid) {
this.upid = upid;
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + id;
result = prime * result + level;
result = prime * result + ((name == null) ? 0 : name.hashCode());
result = prime * result + upid;
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
Os_district other = (Os_district) obj;
if (id != other.id)
return false;
if (level != other.level)
return false;
if (name == null) {
if (other.name != null)
return false;
} else if (!name.equals(other.name))
return false;
if (upid != other.upid)
return false;
return true;
}
@Override
public String toString() {
return "Os_district [id=" + id + ", name=" + name + ", level=" + level
+ ", upid=" + upid + "]";
}
}
Servlet
public class DoServlet extends HttpServlet {
public void service(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
String path = request.getRequestURI();
path = path.substring(path.lastIndexOf("/"), path.lastIndexOf("."));
CityDaoImpl city = new CityDaoImpl();
PrintWriter out = response.getWriter();
if ("/Province".equals(path)) {
try {
JSONArray jsonProcince = JSONArray.fromObject(city
.findAllProvince());
out.println(jsonProcince);
} catch (Exception e) {
e.printStackTrace();
}
}
if ("/City".equals(path)) {
int id = Integer.parseInt(request.getParameter("id"));
try {
JSONArray jsonCity = JSONArray.fromObject(city.findAllByID(id));
out.println(jsonCity);
} catch (Exception e) {
e.printStackTrace();
}
}
if ("/Xian".equals(path)) {
int id = Integer.parseInt(request.getParameter("id"));
try {
JSONArray jsonXian = JSONArray.fromObject(city.findAllByID(id));
out.println(jsonXian);
} catch (Exception e) {
e.printStackTrace();
}
}
if ("/Xiang".equals(path)) {
int id = Integer.parseInt(request.getParameter("id"));
try {
JSONArray jsonXiang = JSONArray
.fromObject(city.findAllByID(id));
out.println(jsonXiang);
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
City.html
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<!--<script type="text/javascript" src="js/my.js"></script>-->
<script type="text/javascript" src="js/jquery-3.3.1.min.js"></script>
<script type="text/javascript">
???????/* function province(){
???????var xhr = getXhr();
???????//alert(xhr);
???????$(‘province‘).innerHTML=‘‘; ?????
???????xhr.open(‘get‘,‘Province.do‘,true);
???????xhr.onreadystatechange=function(){
???????if(xhr.readyState==4&&xhr.status==200){
???????var text=xhr.responseText;
???????var jsontext = JSON.parse(text);
???????for(var i=0;i<jsontext.length;i++){
???????var option = document.createElement("OPTION");
???????//alert(jsontext[i].name);
???????//option.text=jsontext[i].name;
???????option.text=jsontext[i].name;
???????option.value=jsontext[i].id;
???????//alert(jsontext[i].name); ???????
???????$("province").options.add(option);
???????} ???????
???????} ???????
???????};
???????xhr.send(null);
???????
???????}
???????function provinceChange(id){
???????
???????//alert(code);
???????var xhr = getXhr();
???????//alert(xhr);
???????$(‘city‘).innerHTML=‘‘; ??????
???????$(‘xian‘).innerHTML=‘‘;
???????$(‘xiang‘).innerHTML=‘‘;
???????xhr.open(‘get‘,‘City.do?id=‘+id,true);
???????xhr.onreadystatechange=function(){
???????if(xhr.readyState==4&&xhr.status==200){
???????var text=xhr.responseText;
???????var jsontext = JSON.parse(text);
???????for(var i=0;i<jsontext.length;i++){
???????var option = document.createElement("OPTION");
???????
???????option.text=jsontext[i].name;
???????option.value=jsontext[i].id;
???????//alert(jsontext[i].name); ???????
???????$("city").options.add(option);
???????} ???????
???????} ???????
???????};
???????xhr.send(null);
???????
???????}
???????
???????function cityChange(id){
???????
???????//alert(cityCode);
???????var xhr = getXhr();
???????//alert(xhr); ?????
???????$(‘xian‘).innerHTML=‘‘;
???????$(‘xiang‘).innerHTML=‘‘;
???????xhr.open(‘get‘,‘Xian.do?id=‘+id,true);
???????xhr.onreadystatechange=function(){
???????if(xhr.readyState==4&&xhr.status==200){
???????var text=xhr.responseText;
???????//alert(text);
???????var jsontext = JSON.parse(text);
???????//alert(jsontext);
???????for(var i=0;i<jsontext.length;i++){
???????var option = document.createElement("OPTION"); ???????
???????option.text=jsontext[i].name;
???????option.value=jsontext[i].id;
???????//alert(jsontext[i].name); ???????
???????$("xian").options.add(option);
???????} ???????
???????} ???????
???????};
???????xhr.send(null);
???????
???????}
???????
???????function xianChange(id){
???????
???????//alert(cityCode);
???????var xhr = getXhr();
???????//alert(xhr);
???????$(‘xiang‘).innerHTML=‘‘;
???????xhr.open(‘get‘,‘Xiang.do?id=‘+id,true);
???????xhr.onreadystatechange=function(){
???????if(xhr.readyState==4&&xhr.status==200){
???????var text=xhr.responseText;
???????//alert(text);
???????var jsontext = JSON.parse(text);
???????//alert(jsontext);
???????for(var i=0;i<jsontext.length;i++){
???????var option = document.createElement("OPTION"); ???????
???????option.text=jsontext[i].name;
???????option.value=jsontext[i].id;
???????//alert(jsontext[i].name); ???????
???????$("xiang").options.add(option);
???????} ???????
???????} ???????
???????};
???????xhr.send(null);
???????
???????} */
???????
???????$(function(){
????????
????????$.ajax({ ???????
???????‘url‘: ‘Province.do?‘,
??????????‘type‘:‘get‘, ??????
??????????‘dataType‘:‘json‘,
??????????‘success‘:function(data){
??????????
??????????????for(var i=0;i<data.length;i++){
??????????????$(‘#province‘).append("<option value="+data[i].id+">"+data[i].name+"</option>");
??????????????}
??????????},
??????????‘async‘:false
??????????})
??????????
?????????$(‘#province‘).change(function(){
????$(‘#city‘).html("<option>-----请选择城市-----</option>");
????$(‘#xian‘).html("<option>-----请选择县区-----</option>");
????$(‘#xiang‘).html("<option>-----请选择乡镇-----</option>");
????var $obj = $(this).val();
????//alert($obj)
????$.ajax({
????‘url‘:‘City.do‘,
????‘data‘:{‘id‘:$obj},
????‘dataType‘:‘json‘,
????‘success‘:function(data){
????for(var i=0;i<data.length;i++){
????$(‘#city‘).append("<option value="+data[i].id+">"+data[i].name+"</option>");
????}
????}
????})
????})
??????????
????$(‘#city‘).change(function(){
????
????$(‘#xian‘).html("<option>-----请选择县区-----</option>");
????$(‘#xiang‘).html("<option>-----请选择乡镇-----</option>");
????var $obj = $(this).val();
????//alert($obj)
????$.ajax({
????‘url‘:‘Xian.do‘,
????‘data‘:{‘id‘:$obj},
????‘dataType‘:‘json‘,
????‘success‘:function(data){
????for(var i=0;i<data.length;i++){
????$(‘#xian‘).append("<option value="+data[i].id+">"+data[i].name+"</option>");
????}
????}
????})
????})
????
????
????$(‘#xian‘).change(function(){
????
????$(‘#xiang‘).html("<option>-----请选择乡镇-----</option>");
????var $obj = $(this).val();
????//alert($obj)
????$.ajax({
????‘url‘:‘Xiang.do‘,
????‘data‘:{‘id‘:$obj},
????‘dataType‘:‘json‘,
????‘success‘:function(data){
????for(var i=0;i<data.length;i++){
????$(‘#xiang‘).append("<option value="+data[i].id+">"+data[i].name+"</option>");
????}
????}
????})
????})
???????
???????
???????})
???????
???????
???????
</script>
<body align=‘center‘ style=‘top:200px‘>
???<p><b>城市四级联动</b></p>
<select id="province" ?>
<option id="p1">==请选择省份==</option>
</select>
<select id="city" >
<option>==请选择城市==</option>
</select>
<select id="xian" >
<option>==请选择县区==</option>
</select>
<select id="xiang">
<option>==请选择乡镇==</option>
</select>
</body>
</html>
城市四级联动，js和jquery对ajax的支持结合html,json
原文地址：https://www.cnblogs.com/lingl/p/8799357.html