1.以@RequestParam接收

    @PostMapping("ccc1")
    public String ccc1(@RequestParam("name") String name) {
        return name;
    }

2.以实体类方式接收

    @PostMapping("ccc2")
    public String getList(@RequestBody TestUser user) {
        return "success";
    }

3.以map接收

    @PostMapping("ccc")
    public boolean ccc3(@RequestBody Map<String,Object> map) {
        if (map.containsKey("name")){
            String name = map.get("name").toString();
            boolean b = testUserService.selectAllByName(name);
            return b;
        }else {
            return false;
        }
    }

4.List接收
    当前端传来这样一个json数组：[{id,username,password},{id,username,password},    
    {id,username,password},...]时，用List<E>接收

    @PostMapping("getList")
    public String getList(@RequestBody List<TestUser> list) {
        for (TestUser user : list) {
            System.out.println(user.toString());
        }
        return "success";
    }