Spring Boot应用程序MySQL SocketTimeoutException

Question

08:00:31.264 [pool-1-thread-1] ERROR com.zaxxer.hikari.pool.HikariPool - HikariPool-1 - Exception during pool initialization.
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
...
Caused by: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
...
Caused by: java.net.SocketTimeoutException: connect timed out

spring.datasource.url=jdbc:mysql://<server>:3306/<schema>?characterEncoding=UTF-8&useUnicode=true
spring.datasource.username=<username>
spring.datasource.password=<password>
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

... 
<properties>
    ...
    <mysql-connector-java.version>5.1.38</mysql-connector-java.version>
    <spring.boot.version>2.1.3.RELEASE</spring.boot.version>
    ...
</properties>

<dependencies>
    ...
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-jdbc</artifactId>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>${mysql-connector-java.version}</version>
    </dependency>
    ...
</dependencies>
...

Answer 1

1）由于创建的数据库连接不活动而发生

为了避免这种情况，只需在application.properties中添加以下属性即可。

spring.datasource.testWhileIdle = true
spring.datasource.timeBetweenEvictionRunsMillis = 60000
spring.datasource.validationQuery = SELECT 1

这将通过简单地触发SELECT1查询来结束活动。