前后台交互

<form id="sb" action="${pageContext.request.contextPath }/admin/loanContract/addOrUpdate.do" method="post">

　　各种输入框各种值

　　<button class="tjbtn" id="sbm">提 交</button></form>

@RequestMapping("updateSelfdomNeed")
@ResponseBody
    public void updateSelfdomNeed(HttpServletRequest request,HttpServletResponse response){
        String textArea = request.getParameter("textArea");
        String wishId = request.getParameter("wishId");
        int count = selfdomNeedService.updateSelfNeed(wishId,textArea);
        response.setContentType("text/html;charset=utf-8");
        PrintWriter out = null;
        try {
            out = response.getWriter();
            if(count>0){
                out.print("<script>alert(‘处理成功!‘);"
                        + "location.href=‘/CarExchange/admin/selfdomNeed/selfdomNeedList.do‘;</script>  ");
            }
            else{
                out.print("<script>alert(‘处理失败!‘);location.href=‘/CarExchange/admin/selfdomNeed/selfdomNeedList.do‘;</script>  ");
            out.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

$("#sbm").click(function(){
        var sp = $("#sp").html(); 
        
        if(sp!=‘交易订单已存在！‘){
            $("#sb").submit();
            return;
        }
        
        alert(‘交易订单已存在或为空!‘);
        return;
    });
    
    $("#tradeCode").blur(function(){
        
        var tradeCode = $("#tradeCode").val();
        
        $.ajax({
            url:"checkTradeCode.do",
            data:{tradeCode:tradeCode},
            dataType:"json",
            success:function(data){
                var arr = eval(data);
                $("#sp").html(arr.code);
            }
        });
        
    });