Reasons and solutions for the 8-hour difference in mongodb data date display

One 、 See the essence through the phenomenon

1. Background research

Recently, because the project needs to use MongoDB, Use Navicat Premium 15 Client visualizer queries data , But here's the problem , The inserted data shows a difference when viewing 8 Hours , But the program passed new Date() To generate time , System time confirmation is ok , After many tests, it is found that the date obtained by the program call is no problem , Then it can only be the display problem of the client program .

• The normal time is ：

2022-07-03 12:38:11

• Actual storage time

2022-07-03 04:38:11

2. Cause analysis

Time zone difference ：
Stored in mongodb The time in is the standard time UTC +0:00, The time zone of China is +8.00

explain ：UTC namely Universal Time Coordinated, namely 0 The time zone is different from the East eighth District 8 Hours .

3. Impact Assessment

1. Database query data -> Show problems
2. The query data is incorrect -> The return data of the page is also less 8 Hours

Two 、 Solution

2.1. Client display problem

Download visualization tools Robo3T
open Robo3T;

• Click on Options -> display dates in… You can see that there is 2 An option ：
  • 1.UTC( Default )
  • 2.Local TimeZone.
• choice Local TimeZone, Check the data time again , It is found that it is normal .

notes ：UTC namely Universal Time Coordinated, namely 0 The time zone is different from the East eighth District 8 Hours .

2.2. The query data is incorrect

Add @JsonFormat Annotation and configuration

    @JsonFormat(locale = "zh", timezone = "Asia/Shanghai", pattern = "yyyy-MM-dd HH:mm:ss")
    @Field("createTime")
    private Date createTime;            //  Message creation time 

2.3. Effect validation

• Client display problem

• The front end receives messages
  Return time attribute ：createTime

[{
    
	"id": "62c11d3435b7c4007a8e650e",
	"fromUserId": "21100598TZ9XG6RP",
	"fromNickname": " Little beauty ",
	"fromFace": "http://gblfy.cn:9000/imooc/xh.jpg",
	"toUserId": "220620BZ2DH0KP94",
	"msgType": 1,
	"msgContent": {
    
		"isFriend": true
	},
	"createTime": "2022-07-03 12:38:11"
},
... Other data are ignored 
]

• The normal time is ：

2022-07-03 12:38:11

test result ： The return data time is consistent with the correct drop