jquery+ajax+后台级联

$(document).ready(function(){
		 getJsonServicecontent();
	});

	 function getJsonServicecontent(){
	 	$.post   
		(
			'<%=basePath%>/itemgrade/servicestandardAction!queryJsonServicecontent.action?s='+new Date(),
			{    
			  servicelevelid: function(){return $("#servicelevelid").val();}
		   	},    
		    function(data) //回调函数   
		  	{    
		  		$("#servicecontentid").empty();
		  	 	$("#servicecontentid").append($("<option/>").text("请选择").attr("value",""));
		  		$(data).each(function () {
		  			var nametemp=this.name;
		  			if(nametemp.length>4){
		  				nametemp=nametemp.substring(0,4)+"...";
		  			}
                    $("#servicecontentid").append($("<option title="+this.name+" />").text(nametemp).attr("value",this.id));
                    $("#servicecontentid").val('${servicecontentid}');
                });
		  	},   
		  	"json" //返回类型   
		);
	 }

 

<div class="lbsz_content_022" >
              <div class="bddh_content_01" style="padding-left:0px; font-size: 14px;">项目考评管理 &lt; <strong><span style="color:#fa7917;">服务标准管理</span></strong></div>
              <div class="tj_content_211">
                  <table width="744" border="0" cellspacing="0" cellpadding="0" height="50" align="left">
                    <tr>
                      <td width="123" style="color:#333" >　服务标准名称</td>
                      <td width="168">
                       <input name="queryname" value="${queryname}" type="text" class="chaxun_shurukuang" id="queryname" />
                      </td>
                      <td width="78">
                      	服务等级
                      </td>
                      <td width="103">
                      	<select id="servicelevelid" name="servicelevelid" onchange="getJsonServicecontent()">
							<option value="">请选择</option>
							<c:forEach items="${cachemap.servicelevel}" var="servicelevel">
								<option value="${servicelevel.key}" <c:if test='${servicelevel.key==servicelevelid}'>selected="selected"</c:if>>${servicelevel.value}</option>
							</c:forEach>
						</select>
                      </td>
                      <td width="78">
                      	服务内容
                      </td>
                      <td width="103">
                      	<select id="servicecontentid" name="servicecontentid" style="width: 90px;">
						</select>
                      </td>
                      <td width="73"><a href="javascript:void(0)" onclick="queryfun();"><img src="<%=basePath%>images/ny_chaxun.jpg" width="65" height="28" /></a>                      </td>
                      <td width="19"></td>
                      <td width="180" style="color:#333">&nbsp;</td>
                    </tr>
                  </table>
          </div>

 

/**
	 * 根据服务等级查询服务内容
	 * @return
	 */
	public String queryJsonServicecontent(){
		
		HttpServletRequest request = ServletActionContext.getRequest();
		HttpServletResponse response = ServletActionContext.getResponse();
		response.setCharacterEncoding("utf-8");
		String servicelevelid=null;
		if(request.getParameter("servicelevelid")!=null&&!request.getParameter("servicelevelid").equals("")){
			servicelevelid=request.getParameter("servicelevelid");
		}
		String jsonRoad=itemgradeService.queryJsonServicecontent(servicelevelid);
		try {
			PrintWriter out = response.getWriter();
			out.print(jsonRoad);
			out.flush();
			out.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return null;
	}

 

public String queryJsonServicecontent(String servicelevelid) {
		JSONArray jsonArray = new JSONArray();
		List<Servicecontent> servicecontentList=itemgradeDAO.queryJsonServicecontent(servicelevelid);
		for(Servicecontent s:servicecontentList){
			JSONObject jsonobject = new JSONObject();
			try {
				jsonobject.put("id",s.getCode());
				jsonobject.put("name", s.getName());
				jsonArray.put(jsonobject);
			} catch (JSONException e) {
				e.printStackTrace();
			}
		}
		return jsonArray.toString();
	}

 

public List<Servicecontent> queryJsonServicecontent(String servicelevelid){
		return getSqlSession().selectList("itemgrade.queryJsonServicecontent",servicelevelid);
	}

 

<select id="queryJsonServicecontent" resultType="net.hlj.procomplaints.bean.Servicecontent" parameterType="java.lang.String" >
	    select *
	    from TBDIC_SERVICECONTENT
	    where servicelevelid=#{servicelevelid,jdbcType=VARCHAR}
  	</select>