关于超时的原因

Question

项目一段时间就出现这个超时，不知道是什么超时，
2021-04-15 16:18:11.025 ERROR 12784 --- [nio-8080-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.dao.DataAccessResourceFailureException: 30,000 milliseconds timeout on connection http-outgoing-0 [ACTIVE]; nested exception is java.lang.RuntimeException: 30,000 milliseconds timeout on connection http-outgoing-0 [ACTIVE]] with root cause

java.net.SocketTimeoutException: 30,000 milliseconds timeout on connection http-outgoing-0 [ACTIVE]

at org.apache.http.nio.protocol.HttpAsyncRequestExecutor.timeout(HttpAsyncRequestExecutor.java:387) ~[httpcore-nio-4.4.13.jar:4.4.13]
at org.apache.http.impl.nio.client.InternalIODispatch.onTimeout(InternalIODispatch.java:92) ~[httpasyncclient-4.1.4.jar:4.1.4]
at org.apache.http.impl.nio.client.InternalIODispatch.onTimeout(InternalIODispatch.java:39) ~[httpasyncclient-4.1.4.jar:4.1.4]
at org.apache.http.impl.nio.reactor.AbstractIODispatch.timeout(AbstractIODispatch.java:175) ~[httpcore-nio-4.4.13.jar:4.4.13]
at org.apache.http.impl.nio.reactor.BaseIOReactor.sessionTimedOut(BaseIOReactor.java:261) ~[httpcore-nio-4.4.13.jar:4.4.13]
at org.apache.http.impl.nio.reactor.AbstractIOReactor.timeoutCheck(AbstractIOReactor.java:502) ~[httpcore-nio-4.4.13.jar:4.4.13]
at org.apache.http.impl.nio.reactor.BaseIOReactor.validate(BaseIOReactor.java:211) ~[httpcore-nio-4.4.13.jar:4.4.13]
at org.apache.http.impl.nio.reactor.AbstractIOReactor.execute(AbstractIOReactor.java:280) ~[httpcore-nio-4.4.13.jar:4.4.13]
at org.apache.http.impl.nio.reactor.BaseIOReactor.execute(BaseIOReactor.java:104) ~[httpcore-nio-4.4.13.jar:4.4.13]
at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor$Worker.run(AbstractMultiworkerIOReactor.java:591) ~[httpcore-nio-4.4.13.jar:4.4.13]
at java.lang.Thread.run(Thread.java:748) [na:1.8.0_181]

没有多余的报错，我是用swagger请求接口，第一次用springboot项目，各位大神帮分析分析，谢谢

Answer 1

数据库连接失败，看是不是数据库服务没起。