使用 Tomcat 进行连接池时出现 SQLNestedException
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【中文标题】使用 Tomcat 进行连接池时出现 SQLNestedException【英文标题】：SQLNestedException when connection pooling using Tomcat 【发布时间】：2015-12-17 11:12:13 【问题描述】：这是 mysql 的 jdbc connection pooling 的 Resource 配置。
<Resource
abandonWhenPercentageFull="50"
auth="Container"
closeMethod="close"
driverClassName="com.mysql.jdbc.Driver"
global="jdbc/gisdata"
initialSize="34"
logAbandoned="true"
maxActive="377"
maxIdle="233"
maxWait="10000"
minEvictableIdleTimeMillis="55000"
minIdle="89" name="jdbc/gisdata"
password="temp12345"
removeAbandoned="true"
removeAbandonedTimeout="60"
testOnBorrow="true"
timeBetweenEvictionRunsMillis="34000"
type="javax.sql.DataSource"
url="jdbc:mysql://URL:3306/zmaperp_final?allowMultiQueries=true"
username="root"
validationInterval="34000"
validationQuery="SELECT 1"
/>
我收到以下错误：
WARNING: Unexpected exception resolving reference
org.apache.tomcat.dbcp.dbcp.SQLNestedException: Cannot load JDBC driver class 'com.mysql.jdbc.Driver'
at org.apache.tomcat.dbcp.dbcp.BasicDataSource.createConnectionFactory(BasicDataSource.java:1429)
at org.apache.tomcat.dbcp.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1371)
at org.apache.tomcat.dbcp.dbcp.BasicDataSource.getLogWriter(BasicDataSource.java:1098)
at org.apache.tomcat.dbcp.dbcp.BasicDataSourceFactory.createDataSource(BasicDataSourceFactory.java:350)
at org.apache.tomcat.dbcp.dbcp.BasicDataSourceFactory.getObjectInstance(BasicDataSourceFactory.java:156)
at org.apache.naming.factory.ResourceFactory.getObjectInstance(ResourceFactory.java:141)
at javax.naming.spi.NamingManager.getObjectInstance(Unknown Source)
at org.apache.naming.NamingContext.lookup(NamingContext.java:842)
at org.apache.naming.NamingContext.lookup(NamingContext.java:153)
at org.apache.naming.NamingContext.lookup(NamingContext.java:830)
at org.apache.naming.NamingContext.lookup(NamingContext.java:167)
at org.apache.catalina.core.NamingContextListener.addResource(NamingContextListener.java:1103)
at org.apache.catalina.core.NamingContextListener.createNamingContext(NamingContextListener.java:682)
at org.apache.catalina.core.NamingContextListener.lifecycleEvent(NamingContextListener.java:271)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:731)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.startup.Catalina.start(Catalina.java:689)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:294)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:428)
Caused by: java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
at java.net.URLClassLoader$1.run(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at org.apache.tomcat.dbcp.dbcp.BasicDataSource.createConnectionFactory(BasicDataSource.java:1420)
我在 Tomcat 中的系统上使用 Tomcat 实例，并按照推荐添加了 mysql-connector jar 文件：
更新：我已经按照@Jan 的回答更新了jar 文件。错误已更改为如下所示：
WARNING: Unexpected exception resolving reference
org.apache.tomcat.dbcp.dbcp.SQLNestedException: Error preloading the connection pool
at org.apache.tomcat.dbcp.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1398)
at org.apache.tomcat.dbcp.dbcp.BasicDataSource.getLogWriter(BasicDataSource.java:1098)
at org.apache.tomcat.dbcp.dbcp.BasicDataSourceFactory.createDataSource(BasicDataSourceFactory.java:350)
at org.apache.tomcat.dbcp.dbcp.BasicDataSourceFactory.getObjectInstance(BasicDataSourceFactory.java:156)
at org.apache.naming.factory.ResourceFactory.getObjectInstance(ResourceFactory.java:141)
at javax.naming.spi.NamingManager.getObjectInstance(Unknown Source)
at org.apache.naming.NamingContext.lookup(NamingContext.java:842)
at org.apache.naming.NamingContext.lookup(NamingContext.java:153)
at org.apache.naming.NamingContext.lookup(NamingContext.java:830)
at org.apache.naming.NamingContext.lookup(NamingContext.java:167)
at org.apache.catalina.core.NamingContextListener.addResource(NamingContextListener.java:1103)
at org.apache.catalina.core.NamingContextListener.createNamingContext(NamingContextListener.java:682)
at org.apache.catalina.core.NamingContextListener.lifecycleEvent(NamingContextListener.java:271)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:731)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.startup.Catalina.start(Catalina.java:689)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:294)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:428)
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Data source rejected establishment of connection, message from server: "Too many connections"
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:409)
at com.mysql.jdbc.Util.getInstance(Util.java:384)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1013)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:987)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:973)
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1112)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2506)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2539)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2321)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:832)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:409)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:417)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:344)
at org.apache.tomcat.dbcp.dbcp.DriverConnectionFactory.createConnection(DriverConnectionFactory.java:38)
at org.apache.tomcat.dbcp.dbcp.PoolableConnectionFactory.makeObject(PoolableConnectionFactory.java:582)
at org.apache.tomcat.dbcp.pool.impl.GenericObjectPool.addObject(GenericObjectPool.java:1679)
at org.apache.tomcat.dbcp.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1395)
... 23 more
更新
更新了连接属性：
<Resource
abandonWhenPercentageFull="50"
auth="Container"
closeMethod="close"
driverClassName="com.mysql.jdbc.Driver"
global="jdbc/gisdata"
initialSize="10"
logAbandoned="true"
maxActive="25"
maxIdle="10"
maxWait="10000"
minEvictableIdleTimeMillis="55000"
minIdle="5"
name="jdbc/gisdata"
password="temp12345"
removeAbandoned="true"
removeAbandonedTimeout="60"
testOnBorrow="true"
timeBetweenEvictionRunsMillis="34000"
type="javax.sql.DataSource"
url="jdbc:mysql:SERVER/zmaperp_final?allowMultiQueries=true"
username="root"
validationInterval="34000" validationQuery="SELECT 1;"
/>
我现在尝试删除 allowMultiQueries 选项，但连接仍然给我一个错误。
【问题讨论】：
【参考方案1】：您必须添加 Driver，而不是 Sources :-)
检查驱动程序的文件名。你会想要
mysql-connector-java-5.1.37-bin.jar
或带高亮：你有mysql-connector-java-5.1.37-source.jar，你需要mysql-connector-java-5.1.37-bin 。罐
祝你好运:-)
编辑/您的问题已更改
message from server: "Too many connections"
您需要将最大/初始连接数减少到适中。我推荐
maxActive="25"
maxIdle="10"
maxWait="10000"
minEvictableIdleTimeMillis="55000"
minIdle="5"
对于初学者。
【讨论】：
我将jar 更改为bin，但是问题仍然存在。我重新启动了服务器，我收到一个新错误，上面写着Error preloading the connection pool。我已经用新错误更新了问题
我已按照建议进行了更改并减少了连接数，但错误仍然存在。
我已经更新了连接属性，我应该从连接中删除allow multiQueries吗？
让我们continue this discussion in chat。以上是关于使用 Tomcat 进行连接池时出现 SQLNestedException的主要内容，如果未能解决你的问题，请参考以下文章