var param = {};
param.username = username;
$.ajax({
    headers : {
        "content-Type":"application/json;charset=UTF-8"
    },
    url : jsDataPath+‘user/save‘,
    type : ‘POST‘,
    data: JSON.stringify(params),
    success : function (res) {
        if(res.code==200){
            layer.msg(‘添加成功!‘);
            layer.close(index);
            loadUserData();
        }else{
            layer.msg(res.message);
        }
    }
})

后台:

@RequestMapping("/save")
@ResponseBody
public Object save2(@RequestBody SUsers model) {

jquery请求json数据，后台用@RequestBody接收