系统症状：
某个功能报错：
但是数据库链接并没有用完。重启一下tomcat就好了，但是过十几分钟又报错，如此反复。
怀疑是数据库连接泄露。于是加入下面的配置进行调查：
<bean name="dataSource" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close"> ...... <property name="removeAbandoned" value="true" /> <property name="removeAbandonedTimeout" value="180" /> <property name="logAbandoned" value="true" /> </bean>
查到报错信息：
[ERROR] com.alibaba.druid.pool.DruidDataSource.removeAbandoned(DruidDataSource.java:2664):Druid-ConnectionPool-Destroy-1730184957 - abandon connection, owner thread: http-apr-8181-exec-186, connected at : 1560136511767, open stackTrace
at java.lang.Thread.getStackTrace(Thread.java:1559)
at com.alibaba.druid.pool.DruidDataSource.getConnectionDirect(DruidDataSource.java:1311)
at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:1233)
at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:1223)
at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:90)
at org.springframework.jdbc.datasource.DataSourceTransactionManager.doBegin(DataSourceTransactionManager.java:246)
at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:377)
at org.springframework.transaction.interceptor.TransactionAspectSupport.createTransactionIfNecessary(TransactionAspectSupport.java:461)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:277)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:673)
at com.xxxx.controller.FileController.getxxxxjrxx(FileController.java:382)
......
ownerThread current state is BLOCKED, current stackTrace
at java.lang.Throwable.printStackTrace(Throwable.java:655)
at java.lang.Throwable.printStackTrace(Throwable.java:643)
at java.lang.Throwable.printStackTrace(Throwable.java:634)
at com.xxx.service.xxxServiceImpl.getxxx(Btjc01ServiceImpl.java:544)
at com.xxx.service.xxxServiceImpl$$FastClassBySpringCGLIB$$5df1f982.invoke(<generated>)
最后查到是线程被某个外部接口给 BLOCKED，导致其持有的数据库连接无法释放，从而导致数据库连接泄露，从而导致该问题。
其实就是 数据库连接 的 onwerThread 被 blocked了。