Ajax和SpringMVC之间JSON交互

Ajax和SpringMVC之间的json数据传输有两种方式：

1.直接传输Json对象

2.将Json序列化成json字符串

1.直接传输Json对象

前端Ajax

$(document).ready(function(){
    $("#btn_login").click(function(){
        var dataJson = {
            username:$("#username").val(),
            password:$("#password").val()
        };
        $.ajax({
            url:"/login/",
            type:"post",
            data:dataJson,
            contentType:"application/x-www-form-urlencoded",//如不设置此项，默认也为此，设置发送给后端的类型
            dataType:"json",//设置接收后端的数据的类型
            async:true,//设置异步，不然可能接收不到后端返回的json
            success:function(data){//data为后端返回的json
                if(data.code==0){
                    window.location.reload();
                }
                else {                }
            }
        });
    });
});

后端使用

@RequestMapping(path = {"/login/"}, method = {RequestMethod.GET, RequestMethod.POST})
    @ResponseBody
    public String login(@RequestParam("username") String username,
                        @RequestParam("password") String password,
                        HttpServletResponse response) {
        try {
            Map<String, Object> map = userService.login(username, password);
            if (map.containsKey("ticket")) {
                Cookie cookie = new Cookie("ticket", map.get("ticket").toString());
                cookie.setPath("/");
                response.addCookie(cookie);
                //return "redirect:/";
              return CommonUtil.getJSONString(0, "成功");
            } else {
                //return "redirect:/";
                return CommonUtil.getJSONString(1, map);
            }        } catch (Exception e) {
            logger.error("登录异常" + e.getMessage());
            //return "redirect:/";
            return CommonUtil.getJSONString(1, "注册异常");
        }
    }

使用@RequestParam，即使用Servlet的request.getgetParameter。这种方式可以接受以application/x-www-form-urlencoded这种方式传输的JSON对象的。

2.将Json序列化

前端Ajax

$(document).ready(function(){
    $("#btn_reg").click(function(){
        var dataJson = {
            username:$("#regusername").val(),
            password:$("#regpassword").val()
        };
        $.ajax({
            url:"/reg/",
            type:"post",
            contentType:"application/json",//以json字符串形式传输
            data:JSON.stringify(dataJson),//将json对象序列化成字符串
            dataType:"json",
            async:true,
            success:function(data){
                if(data.code==0){
                    window.location.reload();
                }
                else {                }
            }
        });    });
});

后端Controller

@RequestMapping(path = {"/reg/"}, method = {RequestMethod.GET, RequestMethod.POST})
    @ResponseBody
    public String reg(@RequestBody User user,
                      HttpServletResponse response) {
        try {
            Map<String, Object> map = userService.register(user.getUsername(), user.getPassword());
            if (map.containsKey("ticket")) {
                Cookie cookie = new Cookie("ticket", map.get("ticket").toString());
                cookie.setPath("/");                response.addCookie(cookie);
                return CommonUtil.getJSONString(0, "注册成功");
            } else {
                return CommonUtil.getJSONString(1, map);
            }        } catch (Exception e) {
            logger.error("注册异常" + e.getMessage());
            return CommonUtil.getJSONString(1, "注册异常");
        }
    }