matters needing attention

Underlying connection

There is also a parameter accessToUnderlyingConnectionAllowed This parameter sets whether the underlying connection is allowed. If set to true, you can use the following method to obtain the underlying connection:

Connection conn = ds.getConnection();

Connection dconn = ((DelegatingConnection) conn).getInnermostDelegate();

...

conn.close();

false is not enabled by default, because the code logic is incorrect, which may bring risks. It is recommended to use it when you need to directly access the specific functions of the driver, and after many tests, clarify the possible risks of each step of the code.

Idle check problem

When using Ali's SLB, it is recommended to set timebetween evictionrunsmillis to 2 seconds or a negative value (turn off the check mechanism). Otherwise, the connection process will report:

Could not open JDBC Connection for transaction; nested exception is com.mysql.jdbc.exceptions.jdbc4.CommunicaiotnsException: Communications link failure

Different profiles

Spring boot application The configuration in properties is the most complete, which is recommended for reference.

Configuring connection pools in jdbc

jdbc.properties: 
jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://172.49.15.55:3306/testdb?useUnicode=true&characterEncoding=utf-8
jdbc.username=test
jdbc.password=test
jdbc.filters=stat
jdbc.maxActive=300
jdbc.initialSize=2
jdbc.maxWait=60000
jdbc.minIdle=1
jdbc.timeBetweenEvictionRunsMillis=60000
jdbc.minEvictableIdleTimeMillis=300000
jdbc.validationQuery=SELECT 'x'
jdbc.testWhileIdle=true
jdbc.testOnBorrow=false
jdbc.testOnReturn=false
jdbc.poolPreparedStatements=false
jdbc.maxPoolPreparedStatementPerConnectionSize=50

Configuring druid in spring

<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">
      <!-- "Basic properties of connection  -->
      <property name="url" value="jdbc_url" />
      <property name="username" value="${jdbc_user}" />
      <property name="password" value="${jdbc_password}" />
      <!-- Connection pool properties -->
      <property name="initialSize" value="100" />
      <property name="maxActive" value="1000" />
      <property name="maxWait" value="60000" />
      <property name="minEvictableIdleTimeMillis" value=300000 />
      <property name="keepAlive" value=true />
      <property name="timeBetweenEvictionRunsMillis" value=-1 />
      <property name="minIdle" value="20" />
      <property name="removeAbandoned" value="true"/>
      <property name="removeAbandonedTimeout" value="180"/>
      <property name="logAbandoned" value="true" />
      <property name="testWhileIdle" value="true" />
      <property name="validationQuery" value="SELECT 'x'" />
      <property name="testOnBorrow" value="false" />
      <property name="testOnReturn" value="false" />
      <property name="poolPreparedStatements" value="true"/>
      <property name="maxPoolPreparedStatementPerConnectionSize" value="20"/>
      <property name="filters" value="stat,wall,slf4j"/>
      <property name="connectionProperties" value="druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000" />
</bean>

spring boot application.properties configuration

spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
#Driver configuration information
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
#Basic connection information
spring.datasource.username = root
spring.datasource.password = root
spring.datasource.url=jdbc:mysql://192.168.153.23:3306/mytest?useUnicode=true&characterEncoding=utf-8

#Connection pool properties
spring.datasource.druid.initial-size=15
spring.datasource.druid.max-active=100
spring.datasource.druid.min-idle=15
spring.datasource.druid.max-wait=60000
spring.datasource.druid.time-between-eviction-runs-millis=60000
spring.datasource.druid.min-evictable-idle-time-millis=300000
spring.datasource.druid.test-on-borrow=false
spring.datasource.druid.test-on-return=false
spring.datasource.druid.test-while-idle=true
spring.datasource.druid.validation-query=SELECT 1
spring.datasource.druid.validation-query-timeout=1000
spring.datasource.druid.keep-alive=true
spring.datasource.druid.remove-abandoned=true
spring.datasource.druid.remove-abandoned-timeout=180
spring.datasource.druid.log-abandoned=true
spring.datasource.druid.pool-prepared-statements=true
spring.datasource.druid.max-pool-prepared-statement-per-connection-size=20
spring.datasource.druid.filters=stat,wall,slf4j
spring.datasource.druid.use-global-data-source-stat=true
spring.datasource.druid.preparedStatement=true
spring.datasource.druid.maxOpenPreparedStatements=100
spring.datasource.druid.connect-properties.mergeSql=true
spring.datasource.druid.connect-properties.slowSqlMillis=5000

Transferred from: https://www.cnblogs.com/halberd-lee/p/11304790.html