代码程序：
@PostMapping("selectById")@ResponseBodypublic Result selectById(@RequestBody int id) { ??Result result =new Result(); ??List<User> list = userService.selectById(id); ??if(list.size()==1){ ??result.setCode("000"); ??result.setMsg("success"); ??result.setData(list);}else if(list.size()==0){ ?????result.setCode("E01"); ?????result.setMsg("输入的id找不到有效用户"); ?????result.setData(null); ??}else { ?????result.setCode("E02"); ?????result.setMsg("输入的id找到大于1个有效用户"); ?????result.setData(list); ??} ??return result;}
请求内容：
POST http://localhost:8080/user/selectById
POST data:
{
???"id":300
}
返回信息：
{
: ??"timestamp":"2019-02-08T14:05:17.430+0000",
: ??"status":400,
: ??"error":"Bad Request",
: ??"message":"JSON parse error: Cannot deserialize instance of `int` out of START_OBJECT token; nested exception is com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize instance of `int` out of START_OBJECT token\n at [Source: (PushbackInputStream); line: 1, column: 1]",
: ??"path":"/user/selectById"
}
用的是post的方式，传的入参是int id， 不是一个对象。
需要改成对象，然后获取对象的id
@ApiOperation(value = "根据ID查询用户的信息")@PostMapping("selectById")@ResponseBodypublic Result selectById(@RequestBody User user) {Result result =new Result();List<User> list = userService.selectById(user.getId());if(list.size()==1){result.setCode("000");result.setMsg("success");result.setData(list);}else if(list.size()==0){result.setCode("E01");result.setMsg("输入的id找不到有效用户");result.setData(null);}else {result.setCode("E02");result.setMsg("输入的id找到大于1个有效用户");result.setData(list);}return result;}
JSON parse error: Cannot deserialize instance of `int` out of START_OBJECT token; nested exception is com.fasterxml.jackson.databind.exc
原文地址：https://www.cnblogs.com/qianjinyan/p/10356851.html