jquery ajax struts2用户名验证(get)

jquery ajax struts2用户名验证(get)
页面：
 $(document).ready(function(){
  checkConfirm();
 });
//验证用户名是否存在
function checkConfirm(){
$("#userName").blur(function(){
var gradename = $(this).val();
var changeUrl = "<%=path%>/system/SysOperator/checkUserNameAction.action?inputName="+gradename;
$.get(changeUrl,function(str){
if(str == '1'){
$("#gradeInfo").html("<font color=\"red\">您输入的用户名存在！请重新输入！</font>");
}else{
$("#gradeInfo").html("");
}
})
return false;
})
}

 <s:textfield  id="userName" label="1" name="userName" maxlength="16" size="16"/>
            <font color="red">*</font>
            <span id="gradeInfo"></span>
struts2配置文件：
 <!-- 用户名称验证 -->
   <action name="checkUserNameAction" class="qxUserAction" method="checkUserName">
        <result type="stream">
         <param name="contentType">text/html</param>
          <param name="inputName">inputStream</param>
       </result>
         </action>
struts2Action:
    private InputStream inputStream;
  private String inputName;
      public InputStream getInputStream() {
        return inputStream;
    }

    public void setInputStream(InputStream inputStream) {
        this.inputStream = inputStream;
    }

 public String getInputName() {
  return inputName;
 }

 public void setInputName(String inputName) {
  this.inputName = inputName;
 }
 
  public String checkUserName(){
  // 操作员名称不为空时
  if (!StringUtil.isBlank(this.inputName)) {
   // 操作员名称不能重复
   Long operatorNameCount = this.qxUserService
     .checkUserNameExist(this.inputName.trim());
  
   if (operatorNameCount > 0) {
    inputStream=new StringBufferInputStream("1");  
      }else {
       inputStream=new StringBufferInputStream("0");
   }
  }
  return SUCCESS;
 }