<div>  
        
          省份：<select id="province">  
               <option value="">请选择省份</option>  
            </select>  
          城市：<select id="city">  
            <option value="">请选择城市</option>  
            </select>  
    </div>  

    $(document).ready(function(){   
    var province=$("#province");   
    var city=$("#city");   
    var provinceurl="/Struts2/base/selectProvince.action";   
    $.post(provinceurl,{code:"province"},function(data){   
        var dataObj=eval("("+data+")");   
        $.each(dataObj,function(index,item){   
        var tempOption = document.createElement("option");   
        tempOption.value = item.provinceId;   
        tempOption.innerHTML  = item.provinceName;   
        province.append(tempOption);   
        });   
    },"json");   
      
    province.change(function(){   
      city.empty();   
      var params={provinceCode:$('#province option:selected').val()};   
      $.post("/Struts2/base/selectCity.action",params,function(data){   
      alert(data);   
      var dataObj=eval("("+data+")"); //转换为json对象  
        $.each(dataObj,function(index,item){   
        var tempOption = document.createElement("option");   
        tempOption.value = item.cityId;   
        tempOption.innerHTML  = item.cityName;   
        city.append(tempOption);   
        });   
      },"json");   
    });   
    });  

    ackage com.hyts.business.action;  
    import java.util.List;  
    import javax.servlet.http.HttpServletRequest;  
    import net.sf.json.JSONArray;  
    import com.hyts.dao.ProvinceDAO;  
    import com.hyts.model.City;  
    import com.hyts.model.Province;  
    import com.opensymphony.xwork2.ActionSupport;  
    public class ChainSelectAction extends ActionSupport {  
     private static final long serialVersionUID = 1383189653446960523L;  
     private HttpServletRequest request;  
     private String result;//前台接收数据  
     private String provinceCode;  
     public String selectProvince()  {  
      ProvinceDAO provinceDAO=new ProvinceDAO();  
      List<Province> list=provinceDAO.getAllProvince();  
      JSONArray jsonArray2 = JSONArray.fromObject( list );                
      this.result=jsonArray2.toString();  
      return SUCCESS;  
     }  
     public String selectCity() throws Exception{  
      ProvinceDAO provinceDAO=new ProvinceDAO();  
      System.out.println(this.provinceCode);  
      int provinceId=Integer.parseInt(this.provinceCode);  
      List<City> list=provinceDAO.getCityByProvince(provinceId);  
      for(int i=0;i<list.size();i++)  
      {  
       City city=list.get(i);  
       System.out.println(city.getCityName());  
      }  
      JSONArray jsonArray = JSONArray.fromObject( list );  
      this.result=jsonArray.toString();  
      return SUCCESS;  
     }  
     public String getResult() {  
      return result;  
     }  
     public void setResult(String result) {  
      this.result = result;  
     }  
       
     public String getProvinceCode() {  
      return provinceCode;  
     }  
     public void setProvinceCode(String provinceCode) {  
      this.provinceCode = provinceCode;  
     }  
     public void setServletRequest(HttpServletRequest request) {  
      this.request=request;  
     }  
    }  
      
      
    Struts.xml  
    <pre name="code" class="xml"><?xml version="1.0" encoding="UTF-8" ?>  
    <!DOCTYPE struts PUBLIC  
        "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"  
        "http://struts.apache.org/dtds/struts-2.0.dtd">  
    <struts>  
      <include file="struts-default.xml"/>