求救！关于ajax传递内容到action，数据不完整

function addComment() {

	//以下是获取fckeditor的值

	var fck=FCKeditorAPI.GetInstance("u_comment_a.commentContent").GetXHTML(true); 

	var userId=document.getElementById("userId").value;

	var articleId=document.getElementById("articleId").value;

	

	//fck=encodeURI(encodeURI(fck));//转码

	

	alert("用户Id:"+userId);

	alert("文章Id:"+articleId);

	alert("评论内容："+fck);

	

	var xhr=new createXmlHttpRequest();//第一步，获取XHR对象

	xhr.onreadystatechange=function (){//第二部，写监听函数

		if (xhr.readyState == 4) {//条件判定

			if (xhr.status == 200||xhr.status == 304) {

				alert("评论成功！");

				location.reload() ;

			}

		}

	}

	

	xhr.open("post","UserComment!addUsercommentarticle",true);//链接请求

	xhr.setRequestHeader("Content-Type","application/x-www-form-urlencoded")//设置一下请求头

	xhr.send("u_comment_a.commentContent="+fck+"&users.userId="+userId+"&article.articleId="+articleId);//发送

	//return false;

}

/**

	 * 添加一条评论的方法

	 * @return

	 */

	public void addUsercommentarticle() {

		System.out.println(article.getArticleId()+"--------------------articleId--------------------");

		System.out.println(users.getUserId()+"--------------------userId--------------------");

		//解码

		try {

			u_comment_a.setCommentContent(java.net.URLDecoder.decode(u_comment_a.getCommentContent(), "UTF-8"));

		} catch (UnsupportedEncodingException e1) {

			e1.printStackTrace();

		}

		System.out.println(u_comment_a.getCommentContent()+"--------------------u_comment_a------------------------");

		

		try {

			users = UserManagerBean.getUserById(users.getUserId());

			article = ArticleManagerBean.getArticleById(article.getArticleId());

			//每当评论一次就添加一次被评论的次数

			article.setCommentCount(article.getCommentCount()+1);

			//提交更新

			ArticleManagerBean.updateArticle(article);

			//再获取一次

//			article = ArticleManagerBean.getArticleById(article.getArticleId());

			System.out.println(article.getCommentCount()+"====================================");//打印评论次数看看

			//设置评论所属文章及评论者

			u_comment_a.setArticle(article);

			u_comment_a.setUsers(users);

		} catch (Exception e) {

			e.printStackTrace();

		}

		UserCommentArticleManagerBean.addU_A(u_comment_a);

		//return "commentSuccess";

	}

98--------------------articleId--------------------

9--------------------userId--------------------

<p>--------------------u_comment_a------------------------