MySQL -- time zone / connector / driver type

brief introduction

        In this paper, MySQL How to modify the time zone ; Driver version ; Connector and driver version ; Type of drive .

The time zone

error message

java.sql.SQLException: The server time zone value '???ú±ê×??±??' is unrecognized or represents more than one time zone

resolvent

Change the time zone . Modify the following server or client url The connected time zones are OK .

Law 1： Modify the server time zone

The way 1： Command to change

set global time_zone = '+8:00';  ## modify mysql The global time zone is Beijing time , That is where we are 8 District

set time_zone = '+8:00';            ## Modify the current session time zone

flush privileges;                         ## Immediate effect

The way 2： Modify the configuration file

【linux:my.cnf,windows:my.ini】

stay [mysqld] Add the lower line to the area ：

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        default-time_zone = '+8:00'
       
       

        
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restart MySQL service .

Law 2： Modify the client url Connect to the time zone

serverTimezone=xxx

UTC： World equilibrium time （ London time ）（ Earlier than China 8 Hours ）

GMT： GMT （ It's also London time , and UTC The same effect ）

CST： US China region （-6）

GMT%2B8： Beijing time. （+8）

Asia/Shanghai： Shanghai time （+8）（ Equal to Beijing time ）

Asia/Hongkong： Hong Kong time （+8）（ Equal to Beijing time ）

Try to follow this order ：characterEncoding=UTF-8&serverTimezone=Asia/Shanghai

Refer to the following table for the configuration method “ Driver version ”.

Driver version

com.mysql.jdbc.Driver yes mysql-connector-java 5 Of ,com.mysql.cj.jdbc.Driver yes mysql-connector-java 6 Of .

because springboot Support loose matching , therefore utf8 And UTF-8 It's the same .

Mysql5 Of application.yml To configure

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        spring:
        
  datasource:
        
    driver-class-name: com.mysql.jdbc.Driver
        
    url: jdbc:mysql://127.0.0.1:3306/mp?useUnicode=true&characterEncoding=utf8&useSSL=false&serverTimezone=Asia/Shanghai
        
    password: xxx
        
    username: yyy
        
  jpa:
        
    hibernate:
        
      ddl-auto: none
       
       

        
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Mysql6 And above application.yml To configure

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        spring:
        
  datasource:
        
    driver-class-name: com.mysql.cj.jdbc.Driver
        
    url: jdbc:mysql://127.0.0.1:3306/mp?useUnicode=true&characterEncoding=utf8&useSSL=false&serverTimezone=Asia/Shanghai
        
    password: xxx
        
    username: yyy
        
  jpa:
        
    hibernate:
        
      ddl-auto: none
       
       

        
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Connector and driver version

Warning 1： edition

If mysql-connector-java（pom.xml The dependent version of ） With 6.0 The above , but driver Use or ​​com.mysql.jdbc.Driver, I'll call the police ：​​

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        Loading class 'com.mysql.jdbc.Driver'. This is deprecated. The new driver class is 'com.mysql.cj.jdbc.Driver'. 
        
The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.
       
       

        
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At this time, we need to put com.mysql.jdbc.Driver Change it to com.mysql.cj.jdbc.Driver

Warning 2：SSL

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        WARN: Establishing SSL connection without server’s identity verification is not recommended. 
        
According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn’t set. 
        
For compliance with existing applications not using SSL the verifyServerCertificate property is set to ‘false’. 
        
You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.
       
       

        
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translate ：

         Server authentication is not recommended to establish SSL Connect . 

         If not explicitly set ,MySQL 5.5.45+, 5.6.26+ and 5.7.6+ By default, the version requires SSL Connect . 

         In order to comply with the current not used SSL Connected applications ,verifyServerCertificate Property is set to ’false’. 

         If you don't need to use SSL Connect , You need to go through the settings useSSL=false To explicitly disable SSL Connect .  If you need to use SSL Connect , To provide a truststore for server certificate validation , And set up useSSL=true.

Drive type

brief introduction

There are three types , as follows ：

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2. Class.forName("com.mysql.jdbc.Driver");（ recommend ）
3. new com.mysql.jdbc.Driver() ;
4. em.setProperty("jdbc.drivers","com.mysql.jdbc.Driver");
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1. Class.forName("com.mysql.jdbc.Driver"); // Load database driver

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2. Class.forName("com.mysql.jdbc.Driver");  // Load database driver   
3. String url="jdbc:mysql://localhost:3306/databasename";  // Database connection sub protocol   
4. Connection conn=DriverManager.getConnection(url, "username", "password");  
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         This method is because the parameter is a string , So it's easy to modify , Portability is strong . The most common way to register , It's also recommended .

2. new com.mysql.jdbc.Driver() ; // establish driver object , Load database driver

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2.  new com.mysql.jdbc.Driver(); // establish driver object , Load database driver   
3.  String url="jdbc:mysql://localhost:3306/databasename"; // Database connection sub protocol   
4.  Connection conn=DriverManager.getConnection(url,"username","password");  
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         It doesn't need to be written like this DriverManager.registerDriver(new com.mysql.jdbc.Driver()), as a result of com.mysql.jdbc.Driver Class static code, which has been registered  

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        static {  
        
    try {  
        
        java.sql.DriverManager.registerDriver(new Driver());  
        
    } catch (SQLException E) {  
        
        throw new RuntimeException("Can't register driver!");  
        
    }  
        
}
       
       

        
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         from new com.mysql.jdbc.Driver() You can know , Here you need to create an instance of the class . To create an instance of a class, you need to java The class is passed in the file import Import , Otherwise you will report an error . namely ： In this way , The program cannot be separated from the driver class package when compiling , It brings trouble for the program to switch to other databases

3.System.setProperty("jdbc.drivers","com.mysql.jdbc.Driver");

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2. System.setProperty("jdbc.driver","com.mysql.jdbc.Driver"); // System properties specify the database driver   
3. String url="jdbc:mysql://localhost:3306/databasename"; // Database connection sub protocol   
4. Connection conn=DriverManager.getConnection(url,"username","password");  
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         You can import more than one at the same time jdbc drive , Use a colon in the middle “：” Separate , such as System.setProperty("jdbc.drivers","XXXDriver:XXXDriver:XXXDriver"); In this way, three database drivers are registered at one time .