jsp_ajax示例

1jsp

<script type="text/javascript" src="jquery/jquery-1.4.js"></script>

function findFields() {
   var systemId=$("#systemId").val();
   $.get("superFind/ajaxFindFieldsListBySystemId.action?systemId="+systemId,null,callback);
  }
  function callback(data) {
   //取得集合
   var bm_id=document.getElementById("fieldsId");
   //清空原本下拉框中数据
   for(var i=0;i<bm_id.length;i++) {
    bm_id.options[i]=null;
    bm_id.remove(i);
   }
   //将集合添加到下拉框中
   var bmList=data.getElementsByTagName("field");
   for(var i=0;i<bmList.length;i++) {
    var bm=bmList[i];
    var id=bm.getElementsByTagName("fieldId")[0];
    var fieldId=id.firstChild.data;
    var name=bm.getElementsByTagName("fieldName")[0];
    var fieldName=name.firstChild.data;
    bm_id[i]=new Option(fieldName,fieldId);
   }
  }

 

 

html

<td width="550">
            按系统查找：
            <select name="systemId" id="systemId"
             onchange="findFields()">
             <option value="0">
              --请选择--
             </option>
             <c:forEach var="sysFlag" items="${systemList}">
              <option value="${sysFlag.sid}">
               ${sysFlag.name}
              </option>
             </c:forEach>
            </select>
           </td>

 

 

2struts.xml

 <!-- ajax 取系统ID下的栏目列表 -->
  <action name="ajaxFindFieldsListBySystemId"
   class="superFindAction"
   method="ajaxFindFieldsListBySystemIdMethod">
   <param name="systemId"></param>
   <result name="error">/admin/adminError.jsp</result>
  </action>

3.java class

/**
  * ajax 找到系统ID对下的栏目集合
  * @return
  */
 public String ajaxFindFieldsListBySystemIdMethod(){
  fieldsList = model.superFindFieldsBySystemId(systemId);
  HttpServletResponse response = ServletActionContext.getResponse();
  response.setContentType("text/xml;charset=utf-8");
  try {
   PrintWriter out = response.getWriter();
   out.print("<fieldsList>");
   out.print("<field>");
   out.print("<fieldId>"+"0"+"</fieldId>");
   out.print("<fieldName>"+"--请选择--"+"</fieldName>");
   out.print("</field>");
   if(fieldsList.size()!=0) {
    
    for(int i=0;i<fieldsList.size();i++) {
     Fieldsinfo field=(Fieldsinfo) fieldsList.get(i);
     out.print("<field>");
     out.print("<fieldId>"+field.getFieldId()+"</fieldId>");
     out.print("<fieldName>"+field.getFieldName()+"</fieldName>");
     out.print("</field>");
    }
   }
   out.print("</fieldsList>");
   fieldsList = null;
  } catch (IOException e) {
   System.out.println("向页面打印集合异常");
  }
  return null;
 }