Java provinces and cities cascading drop-down Menu Instance Code _java

This example for you to share the Java provinces and cities of the specific code for your reference, the specific content as follows

1.loadareaservlet.java

Package com.scce.servlet;
Import java.io.IOException;
Import Java.io.PrintWriter;
 
Import java.util.ArrayList;
Import javax.servlet.ServletException;
Import Javax.servlet.http.HttpServlet;
Import Javax.servlet.http.HttpServletRequest;
 
Import Javax.servlet.http.HttpServletResponse;
 
Import Net.sf.json.JSONArray;
Import com.scce.pojo.City;
 
Import Com.scce.pojo.Prov;
 
  public class Loadareaservlet extends HttpServlet {private static final long serialversionuid = 1L;
      public void doget (HttpServletRequest request, httpservletresponse response) throws Servletexception, IOException {
  This.dopost (request, response); public void DoPost (HttpServletRequest request, httpservletresponse response) throws Servletexception, Ioex
    ception {response.setcontenttype ("text/html;charset=utf-8");
    Request.setcharacterencoding ("Utf-8");
    PrintWriter out = Response.getwriter ();
    arraylist<prov> Provs = new arraylist<prov> (); StrinG Provinceid = Request.getparameter ("Provinceid");
    if (provinceid== "" | | | provinceid==null) {System.out.println ("Loading prefecture-level information");
    Prov Pro1 = new Prov ();
    Pro1.setid (0);
    Pro1.setprovincename ("Hubei");
    Prov Pro2 = new Prov ();
    Pro2.setid (1);
    Pro2.setprovincename ("Hunan");
    Prov Pro3 = new Prov ();
    Pro3.setid (2);
    Pro3.setprovincename ("Guangdong");
    Prov Pro4 = new Prov ();
    Pro4.setid (3);
    Pro4.setprovincename ("Guangxi");
    Provs.add (Pro1);
    Provs.add (PRO2);
    Provs.add (PRO3);
    Provs.add (Pro4); System.out.println (Jsonarray.fromobject (Provs). toString ());
    [{"id": 0, "provincename": "Hubei"},{}] Out.print (Jsonarray.fromobject (Provs). toString ());
      }else{arraylist<city> citys = new arraylist<city> ();
        if (Provinceid.equals ("0")) {City city1 = new City ();
        City1.setid (0);
        City1.setcityname ("Wuhan City");
        City City2 = new City ();
        City2.setid (1);
        City2.setcityname ("Huangshi"); City City3 = new City ();
        City3.setid (2);
        City3.setcityname ("Shiyan");
        Citys.add (city1);
        Citys.add (City2);
      Citys.add (CITY3);
        } if (Provinceid.equals ("1")) {City city1 = new City ();
        City1.setid (0);
        City1.setcityname ("Changsha");
        City City2 = new City ();
        City2.setid (1);
        City2.setcityname ("Yueyang");
        City City3 = new City ();
        City3.setid (2);
        City3.setcityname ("Xiangtan");
        Citys.add (city1);
        Citys.add (City2);
      Citys.add (CITY3);
      } System.out.println (Jsonarray.fromobject (citys). toString ());
    Out.print (Jsonarray.fromobject (citys). toString ()); }  
  }
   
 
}

2.test1.html

<! DOCTYPE html>  

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