我正在尝试使用Hibernate从tomcat webapp连接到localhost上的MySql（= MariaDB）（让我们称之为A），但不断收到通信链接失败（下面附带完整的异常跟踪）。
我在另一台计算机上有另一个数据库副本（我们称之为B），还使用第三台计算机进行开发（我们称之为C）。
1）从C连接到任何一个DB（A＆amp; B）都没有问题。 2）在“A”上我没有问题本地连接到DB（运行'mysql -u'命令）。我也没有问题在端口3306上telnet到A或B.所以我假设两个数据库都已启动并且正在运行并可用于连接。
唯一的问题是当我尝试从生产tomcat（在A上运行）连接到A或B db时。我收到错误：
com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
从这个错误的类似案例中，我看到大多数错误是由于无效的用户/通行证或非法IP造成的。我还尝试将ip更改为localhost，127.0.0.1和10.90.41.155（这是该机器的实际ip）。没有任何帮助，并且还要记住，连接只能从A上的特定tomcat安装失败。
我还尝试了以下方法： 1）在catalina启动时添加了“-Djava.net.preferIPv4Stack = true” 2）试图连接到非法地址/端口 - 这改变了（如预期的）从“权限被拒绝”到“无路由到主机”的最终错误。 3）在我的连接字符串中添加了以下内容：“autoReconnect = true＆amp; useUnicode = true＆amp; createDatabaseIfNotExist = true＆amp; characterEncoding = utf-8” - 这导致了相同的错误（“尝试重新连接3次。放弃。”+“权限否认（连接失败）“ 4）尝试了两个DB网址。对于本地数据库尝试使用localhost，127.0.0.1和实际的ip。在连接字符串
中尝试使用和不使用“：3306”附件是hibernate.cfg文件+异常的完整服务器跟踪：
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-configuration SYSTEM
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.dialect">
org.hibernate.dialect.MySQLDialect
</property>
<property name="hibernate.connection.driver_class">
com.mysql.jdbc.Driver
</property>
<!-- Assume test is the database name -->
<property name="hibernate.connection.url">
jdbc:mysql://10.90.41.151/boonder
</property>
<property name="hibernate.connection.username">
root
</property>
<property name="hibernate.connection.password">
XXXXXXXXXX
</property>
<!-- List of XML mapping files -->
<mapping resource="User.hbm.xml"/>
<mapping resource="Issue.hbm.xml"/>
<mapping resource="TraderIssue.hbm.xml"/>
</session-factory>
</hibernate-configuration>
例外是：
type Exception report
message Handler dispatch failed; nested exception is java.lang.ExceptionInInitializerError
description The server encountered an internal error that prevented it from fulfilling this request.
exception
org.springframework.web.util.NestedServletException: Handler dispatch failed; nested exception is java.lang.ExceptionInInitializerError
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:982)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
javax.servlet.http.HttpServlet.service(HttpServlet.java:650)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
com.aldondy.boonder.web.controllers.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:27)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
root cause
java.lang.ExceptionInInitializerError
com.aldondy.boonder.bl.DataSingleton.<init>(DataSingleton.java:54)
com.aldondy.boonder.bl.DataSingleton.instance(DataSingleton.java:74)
com.aldondy.boonder.web.controllers.LoginCtrl.loginInner(LoginCtrl.java:62)
com.aldondy.boonder.web.controllers.LoginCtrl.login(LoginCtrl.java:41)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:498)
org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:180)
org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:440)
org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:428)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
javax.servlet.http.HttpServlet.service(HttpServlet.java:650)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
com.aldondy.boonder.web.controllers.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:27)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
root cause
org.hibernate.service.spi.ServiceException: Unable to create requested service [org.hibernate.engine.jdbc.env.spi.JdbcEnvironment]
org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:271)
org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:233)
org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:210)
org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:51)
org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:94)
org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:242)
org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:210)
org.hibernate.boot.model.process.spi.MetadataBuildingProcess.handleTypes(MetadataBuildingProcess.java:352)
org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:111)
org.hibernate.boot.model.process.spi.MetadataBuildingProcess.build(MetadataBuildingProcess.java:83)
org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:418)
org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:87)
org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:691)
org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:726)
com.aldondy.boonder.bl.DataSingleton.<init>(DataSingleton.java:48)
com.aldondy.boonder.bl.DataSingleton.instance(DataSingleton.java:74)
com.aldondy.boonder.web.controllers.LoginCtrl.loginInner(LoginCtrl.java:62)
com.aldondy.boonder.web.controllers.LoginCtrl.login(LoginCtrl.java:41)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:498)
org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:180)
org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:440)
org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:428)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
javax.servlet.http.HttpServlet.service(HttpServlet.java:650)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
com.aldondy.boonder.web.controllers.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:27)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
root cause
org.hibernate.exception.JDBCConnectionException: Error calling Driver#connect
org.hibernate.exception.internal.SQLStateConversionDelegate.convert(SQLStateConversionDelegate.java:115)
org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator$1$1.convert(BasicConnectionCreator.java:101)
org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator.convertSqlException(BasicConnectionCreator.java:123)
org.hibernate.engine.jdbc.connections.internal.DriverConnectionCreator.makeConnection(DriverConnectionCreator.java:41)
org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator.createConnection(BasicConnectionCreator.java:58)
org.hibernate.engine.jdbc.connections.internal.PooledConnections.addConnections(PooledConnections.java:123)
org.hibernate.engine.jdbc.connections.internal.PooledConnections.<init>(PooledConnections.java:42)
org.hibernate.engine.jdbc.connections.internal.PooledConnections.<init>(PooledConnections.java:20)
org.hibernate.engine.jdbc.connections.internal.PooledConnections$Builder.build(PooledConnections.java:161)
...
org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:691)
org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:726)
com.aldondy.boonder.bl.DataSingleton.<init>(DataSingleton.java:48)
com.aldondy.boonder.bl.DataSingleton.instance(DataSingleton.java:74)
com.aldondy.boonder.web.controllers.LoginCtrl.loginInner(LoginCtrl.java:62)
com.aldondy.boonder.web.controllers.LoginCtrl.login(LoginCtrl.java:41)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:498)
org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:180)
org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:440)
org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:428)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
javax.servlet.http.HttpServlet.service(HttpServlet.java:650)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
com.aldondy.boonder.web.controllers.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:27)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
root cause
com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:166)
com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:58)
com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:853)
com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:440)
com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:241)
com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:221)
org.hibernate.engine.jdbc.connections.internal.DriverConnectionCreator.makeConnection(DriverConnectionCreator.java:38)
org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator.createConnection(BasicConnectionCreator.java:58)
...
org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:210)
org.hibernate.boot.model.process.spi.MetadataBuildingProcess.handleTypes(MetadataBuildingProcess.java:352)
org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:111)
org.hibernate.boot.model.process.spi.MetadataBuildingProcess.build(MetadataBuildingProcess.java:83)
org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:418)
org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:87)
org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:691)
org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:726)
com.aldondy.boonder.bl.DataSingleton.<init>(DataSingleton.java:48)
com.aldondy.boonder.bl.DataSingleton.instance(DataSingleton.java:74)
com.aldondy.boonder.web.controllers.LoginCtrl.loginInner(LoginCtrl.java:62)
com.aldondy.boonder.web.controllers.LoginCtrl.login(LoginCtrl.java:41)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:498)
org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:180)
org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:440)
org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:428)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
javax.servlet.http.HttpServlet.service(HttpServlet.java:650)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
com.aldondy.boonder.web.controllers.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:27)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
root cause
com.mysql.cj.core.exceptions.CJCommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
java.lang.reflect.Constructor.newInstance(Constructor.java:423)
com.mysql.cj.core.exceptions.ExceptionFactory.createException(ExceptionFactory.java:54)
com.mysql.cj.core.exceptions.ExceptionFactory.createException(ExceptionFactory.java:93)
com.mysql.cj.core.exceptions.ExceptionFactory.createException(ExceptionFactory.java:133)
com.mysql.cj.core.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:149)
com.mysql.cj.mysqla.io.MysqlaSocketConnection.connect(MysqlaSocketConnection.java:83)
com.mysql.cj.mysqla.MysqlaSession.connect(MysqlaSession.java:204)
com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:975)
com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:843)
com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:440)
com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:241)
com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:221)
org.hibernate.engine.jdbc.connections.internal.DriverConnectionCreator.makeConnection(DriverConnectionCreator.java:38)
org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator.createConnection(BasicConnectionCreator.java:58)
org.hibernate.engine.jdbc.connections.internal.PooledConnections.addConnections(PooledConnections.java:123)
org.hibernate.engine.jdbc.connections.internal.PooledConnections.<init>(PooledConnections.java:42)
org.hibernate.engine.jdbc.connections.internal.PooledConnections.<init>(PooledConnections.java:20)
org.hibernate.engine.jdbc.connections.internal.PooledConnections$Builder.build(PooledConnections.java:161)
org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.buildPool(DriverManagerConnectionProviderImpl.java:109)
org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure(DriverManagerConnectionProviderImpl.java:72)
org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:94)
org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:242)
org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:51)
org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:94)
org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:242)
org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:210)
org.hibernate.boot.model.process.spi.MetadataBuildingProcess.handleTypes(MetadataBuildingProcess.java:352)
org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:111)
org.hibernate.boot.model.process.spi.MetadataBuildingProcess.build(MetadataBuildingProcess.java:83)
org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:418)
org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:87)
org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:691)
org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:726)
com.aldondy.boonder.bl.DataSingleton.<init>(DataSingleton.java:48)
com.aldondy.boonder.bl.DataSingleton.instance(DataSingleton.java:74)
com.aldondy.boonder.web.controllers.LoginCtrl.loginInner(LoginCtrl.java:62)
com.aldondy.boonder.web.controllers.LoginCtrl.login(LoginCtrl.java:41)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:498)
org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:180)
org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:440)
org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:428)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
javax.servlet.http.HttpServlet.service(HttpServlet.java:650)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
com.aldondy.boonder.web.controllers.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:27)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
root cause
java.net.SocketException: Permission denied (connect failed)
java.net.PlainSocketImpl.socketConnect(Native Method)
java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
java.net.Socket.connect(Socket.java:589)
com.mysql.cj.core.io.StandardSocketFactory.connect(StandardSocketFactory.java:202)
com.mysql.cj.mysqla.io.MysqlaSocketConnection.connect(MysqlaSocketConnection.java:57)
com.mysql.cj.mysqla.MysqlaSession.connect(MysqlaSession.java:204)
com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:975)
com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:843)
com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:440)
com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:241)
com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:221)
org.hibernate.engine.jdbc.connections.internal.DriverConnectionCreator.makeConnection(DriverConnectionCreator.java:38)
org.hibernate.engine.jdbc.connections.internal.BasicConnectionCreator.createConnection(BasicConnectionCreator.java:58)
org.hibernate.engine.jdbc.connections.internal.PooledConnections.addConnections(PooledConnections.java:123)
org.hibernate.engine.jdbc.connections.internal.PooledConnections.<init>(PooledConnections.java:42)
org.hibernate.engine.jdbc.connections.internal.PooledConnections.<init>(PooledConnections.java:20)
org.hibernate.engine.jdbc.connections.internal.PooledConnections$Builder.build(PooledConnections.java:161)
org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.buildPool(DriverManagerConnectionProviderImpl.java:109)
org.hibernate.engine.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure(DriverManagerConnectionProviderImpl.java:72)
org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:94)
org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:242)
org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:210)
org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.buildJdbcConnectionAccess(JdbcEnvironmentInitiator.java:145)
org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:66)
org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:35)
org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.initiateService(StandardServiceRegistryImpl.java:88)
org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:259)
org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:233)
org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:210)
...
org.hibernate.boot.internal.MetadataBuilderImpl.build(MetadataBuilderImpl.java:87)
org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:691)
org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:726)
com.aldondy.boonder.bl.DataSingleton.<init>(DataSingleton.java:48)
com.aldondy.boonder.bl.DataSingleton.instance(DataSingleton.java:74)
com.aldondy.boonder.web.controllers.LoginCtrl.loginInner(LoginCtrl.java:62)
com.aldondy.boonder.web.controllers.LoginCtrl.login(LoginCtrl.java:41)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:498)
org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:428)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
javax.servlet.http.HttpServlet.service(HttpServlet.java:650)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
com.aldondy.boonder.web.controllers.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:27)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
note The full stack trace of the root cause is available in the Apache Tomcat/7.0.76 logs.
答案 0 :(得分：9)
我也跟踪了这个问题。我的症状与你的症状完全相同，我甚至尝试过你尝试过的确切事物。总之，我的问题只发生，因为我在使用SELinux的centos上使用tomcat。
有些人帮助我诊断使用以下命令来查看安全事件以及为什么某些操作不被允许：
sudo ausearch -m avc
sudo grep "tcp_socket" /var/log/audit/audit.log | audit2why // translates log into some human readable reasons why the audit record was generated
我看到了以下条目：
type = AVC msg = audit（1507861264.561：64750）：avc：denied {name_connect } for pid = 1326 comm =“java”dest = 3306 scontext = system_u：system_r：tomcat_t：S0 tcontext = system_u：object_r：mysqld_port_t：s0 tclass = tcp_socket
原因是：缺少类型强制执行（TE）允许规则。
您可以使用audit2allow生成可加载模块以允许此访问。
然后发现这篇关于tomcat和SELinux https://noobient.com/post/165972214381/selinux-woes-with-tomcat-on-centos-74
的文章您可以运行以下命令来查看tomcat是否在tomcat_t安全上下文中运行。
$ps auxZ | grep tomcat
为了真正确定我的错误是否为SELinux，我禁用了SELinux
$ sestatus // shows: SELinux status: enabled
$ sudo vim /etc/selinux/config // set "SELINUX=disabled"
$ sudo shutdown -r now
$ sestatus // shows: SELinux status: disabled
重启我的机器，发现tomcat正在进行出站连接。
很好，现在我至少知道为什么会发生这种情况。当然，如果你需要SELinux，禁用它不是一个解决方案。可能不是解决方案的另一种解决方法是在不经过yum的情况下安装tomcat。 Yum将使用安全上下文安装tomcat。
我认为现在的行动方针是修改管理tomcat的安全上下文或一组规则，以允许它进行传出连接。
答案 1 :(得分：1)
此命令解决了我相同的权限问题：
setsebool -P tomcat_can_network_connect_db 1