java.sql.SQLException:无法获取连接，池错误 等待空闲对象超时.如何恢复连接

Question

我使用 java 8 和 apache tomcat。

执行项目时，出现以下错误

java.sql.SQLException: Cannot get a connection, pool error Timeout waiting for idle object
at org.apache.tomcat.dbcp.dbcp2.PoolingDataSource.getConnection(PoolingDataSource.java:142)
at org.apache.tomcat.dbcp.dbcp2.BasicDataSource.getConnection(BasicDataSource.java:809)
Caused by: java.util.NoSuchElementException: Timeout waiting for idle object
at org.apache.tomcat.dbcp.pool2.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:438)
at org.apache.tomcat.dbcp.pool2.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:348)
at org.apache.tomcat.dbcp.dbcp2.PoolingDataSource.getConnection(PoolingD

我在另一个问题中读到，

数据库已关闭或无法访问。 连接池(设置为 100 最大活动(已断开连接。

现在，我想知道如何恢复数据库以初始化连接。

编辑

下面的代码重复了很多次

final InitialContext contextoInicial = new InitialContext();
final Context contexto = (Context)contextoInicial.lookup("");
final DataSource ds = (DataSource)contexto.lookup("");
Connection  conn = ds.getConnection();

如何重复使用连接并验证是否存在

编辑

java.sql.SQLException: Cannot get a connection, pool error Timeout waiting for idle object
at org.apache.tomcat.dbcp.dbcp2.PoolingDataSource.getConnection(PoolingDataSource.java:142)
at org.apache.tomcat.dbcp.dbcp2.BasicDataSource.getConnection(BasicDataSource.java:753)
at es.magrama.ayudaapi.servlets.JSON.validaRega(JSON.java:249)
at es.magrama.ayudaapi.servlets.JSON.doPost(JSON.java:125)
at es.magrama.ayudaapi.servlets.JSON.doGet(JSON.java:89)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:526)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:678)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:861)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1579)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.util.NoSuchElementException: Timeout waiting for idle object
at org.apache.tomcat.dbcp.pool2.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:438)
at org.apache.tomcat.dbcp.pool2.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:348)
at org.apache.tomcat.dbcp.dbcp2.PoolingDataSource.getConnection(PoolingDataSource.java:134)
... 28 more

Answer 1

异常显示"连接池已耗尽"问题，因为连接未关闭并返回到池，或者这是因为数据源中定义的最大活动连接数足够小，可以处理系统的当前高负载。我怀疑最大活动计数参数(此处为 maxActive=50(可能会导致在高峰时间处理应用程序负载的连接数量减少。

同样在您的代码中(根据您的评论(我看到您已经初始化了很多时间数据源。我建议您初始化一次，然后将其用于连接，例如单例对象。