MySQLNonTransientConnectionException: Quá nhiều kết nối

Question

Ứng dụng Spring-MVC của tôi đôi khi gặp sự cố khi điều hướng xung quanh trang web, thông báo lỗi tôi nhận được từ nhật ký được tìm thấy bên dưới. Tôi hoàn toàn không có ý tưởng về những gì đang gây ra điều này và sẽ rất biết ơn đối với bất kỳ lời khuyên mà sẽ dẫn tôi đi đúng hướng.

SEVERE: Servlet.service() for servlet HS threw exception 
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(NativeConstructorAccessorImpl.java:57) 
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) 
    at java.lang.reflect.Constructor.newInstance(Constructor.java:532) 
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:407) 
    at com.mysql.jdbc.Util.getInstance(Util.java:382) 
    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:982) 
    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1116) 
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2338) 
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2371) 
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2163) 
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:794) 
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47) 
    at sun.reflect.GeneratedConstructorAccessor56.newInstance(Unknown Source) 
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) 
    at java.lang.reflect.Constructor.newInstance(Constructor.java:532) 
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:407) 
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:378) 
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:305) 
    at org.apache.commons.dbcp.DriverConnectionFactory.createConnection(DriverConnectionFactory.java:38) 
    at org.apache.commons.dbcp.PoolableConnectionFactory.makeObject(PoolableConnectionFactory.java:582) 
    at org.apache.commons.dbcp.BasicDataSource.validateConnectionFactory(BasicDataSource.java:1556) 
    at org.apache.commons.dbcp.BasicDataSource.createPoolableConnectionFactory(BasicDataSource.java:1545) 
    at org.apache.commons.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1388) 
    at org.apache.commons.dbcp.BasicDataSource.getConnection(BasicDataSource.java:1044) 
    at org.springframework.orm.hibernate3.LocalDataSourceConnectionProvider.getConnection(LocalDataSourceConnectionProvider.java:81) 
    at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:446) 
    at org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:167) 
    at org.hibernate.jdbc.AbstractBatcher.prepareQueryStatement(AbstractBatcher.java:161) 
    at org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1577) 
    at org.hibernate.loader.Loader.doQuery(Loader.java:696) 
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259) 
    at org.hibernate.loader.Loader.doList(Loader.java:2232) 
    at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2129) 
    at org.hibernate.loader.Loader.list(Loader.java:2124) 
    at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:401) 
    at org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:363) 
    at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:196) 
    at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1149) 
    at org.hibernate.impl.QueryImpl.list(QueryImpl.java:102) 
    at org.springframework.orm.hibernate3.HibernateTemplate$30.doInHibernate(HibernateTemplate.java:921) 
    at org.springframework.orm.hibernate3.HibernateTemplate$30.doInHibernate(HibernateTemplate.java:1) 
    at org.springframework.orm.hibernate3.HibernateTemplate.doExecute(HibernateTemplate.java:406) 
    at org.springframework.orm.hibernate3.HibernateTemplate.executeWithNativeSession(HibernateTemplate.java:374) 
    at org.springframework.orm.hibernate3.HibernateTemplate.find(HibernateTemplate.java:912) 
    at org.springframework.orm.hibernate3.HibernateTemplate.find(HibernateTemplate.java:904) 
    at se.hs.daos.UserDAOImpl.findByName(UserDAOImpl.java:42) 
    at se.hs.controllers.LoginController.checkPassword(LoginController.java:20) 
    at se.hs.pagecontrollers.LoginPageController.submitForm(LoginPageController.java:26) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    at java.lang.reflect.Method.invoke(Method.java:616) 
    at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:176) 
    at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:426) 
    at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:414) 
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:790) 
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719) 
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:644) 
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:560) 
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:637) 
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) 
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) 
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) 
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233) 
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) 
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) 
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) 
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) 
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298) 
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859) 
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588) 
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489) 
    at java.lang.Thread.run(Thread.java:636) 

gì UserDaoImpl của tôi trông giống như:

package se.hs.daos; 

import java.util.List; 

import org.hibernate.SessionFactory; 
import org.springframework.context.ApplicationContext; 
import org.springframework.context.support.ClassPathXmlApplicationContext; 
import org.springframework.orm.hibernate3.HibernateTemplate; 
import org.springframework.orm.hibernate3.support.HibernateDaoSupport; 

import se.hs.models.User; 

public class UserDAOImpl extends HibernateDaoSupport implements UserDAO { 

    private ApplicationContext context = new ClassPathXmlApplicationContext(
      "classpath*:applicationContext.xml"); 
    private SessionFactory sessionFactory = (SessionFactory) context 
      .getBean("mySessionFactory"); 
    private HibernateTemplate hibernateTemplate = new HibernateTemplate(
      sessionFactory, true); 

    public void saveUser(User user) { 
     hibernateTemplate.save(user); 
    } 

    public User getUserById(Integer id) { 

     User userFromDB = hibernateTemplate.get(User.class, id); 
     return userFromDB; 
    } 

    public void removeUser(User user) { 
     hibernateTemplate.delete(user); 
    } 

    public User findByName(String name) { 

     String query = "SELECT u.userId FROM User u WHERE u.userName='" + name 
       + "'"; 

     @SuppressWarnings("unchecked") 
     List<Integer> list = hibernateTemplate.find(query); 

     User userFromDB = null; 

     if (list.size() > 0) { 
      userFromDB = getUserById(list.get(0)); 
     } 

     return userFromDB; 
    } 

} 

UPDATE:

exception 

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.springframework.jdbc.UncategorizedSQLException: Hibernate operation: Cannot release connection; uncategorized SQLException for SQL [???]; SQL state [null]; error code [0]; Already closed.; nested exception is java.sql.SQLException: Already closed. 
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:656) 
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:560) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:637) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717) 
root cause 

org.springframework.jdbc.UncategorizedSQLException: Hibernate operation: Cannot release connection; uncategorized SQLException for SQL [???]; SQL state [null]; error code [0]; Already closed.; nested exception is java.sql.SQLException: Already closed. 
    org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:83) 
    org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:80) 
    org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:80) 
    org.springframework.orm.hibernate3.HibernateAccessor.convertJdbcAccessException(HibernateAccessor.java:424) 
    org.springframework.orm.hibernate3.HibernateAccessor.convertHibernateAccessException(HibernateAccessor.java:410) 
    org.springframework.orm.hibernate3.HibernateTemplate.doExecute(HibernateTemplate.java:411) 
    org.springframework.orm.hibernate3.HibernateTemplate.executeWithNativeSession(HibernateTemplate.java:374) 
    org.springframework.orm.hibernate3.HibernateTemplate.save(HibernateTemplate.java:683) 
    se.hsr.daos.InfoTextDAOImpl.saveInfoText(InfoTextDAOImpl.java:26) 
    se.hsr.controllers.InfoTextController.saveInfoText(InfoTextController.java:31) 
    se.hsr.pagecontrollers.InfoTextPageController.submitForm(InfoTextPageController.java:35) 
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) 
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    java.lang.reflect.Method.invoke(Method.java:616) 
    org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:176) 
    org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:426) 
    org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:414) 
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:790) 
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719) 
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:644) 
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:560) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:637) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717) 
root cause 

java.sql.SQLException: Already closed. 
    org.apache.commons.dbcp.PoolableConnection.close(PoolableConnection.java:114) 
    org.apache.commons.dbcp.PoolingDataSource$PoolGuardConnectionWrapper.close(PoolingDataSource.java:191) 
    org.springframework.orm.hibernate3.LocalDataSourceConnectionProvider.closeConnection(LocalDataSourceConnectionProvider.java:95) 
    org.hibernate.jdbc.ConnectionManager.closeConnection(ConnectionManager.java:474) 
    org.hibernate.jdbc.ConnectionManager.aggressiveRelease(ConnectionManager.java:429) 
    org.hibernate.jdbc.ConnectionManager.afterStatement(ConnectionManager.java:304) 
    org.hibernate.jdbc.AbstractBatcher.closePreparedStatement(AbstractBatcher.java:572) 
    org.hibernate.jdbc.AbstractBatcher.closeStatement(AbstractBatcher.java:291) 
    org.hibernate.id.insert.AbstractReturningDelegate.releaseStatement(AbstractReturningDelegate.java:82) 
    org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:60) 
    org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2176) 
    org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2656) 
    org.hibernate.action.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:71) 
    org.hibernate.engine.ActionQueue.execute(ActionQueue.java:279) 
    org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:321) 
    org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:204) 
    org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:130) 
    org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:210) 
    org.hibernate.event.def.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:56) 
    org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:195) 
    org.hibernate.event.def.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:50) 
    org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:93) 
    org.hibernate.impl.SessionImpl.fireSave(SessionImpl.java:563) 
    org.hibernate.impl.SessionImpl.save(SessionImpl.java:551) 
    org.hibernate.impl.SessionImpl.save(SessionImpl.java:547) 
    org.springframework.orm.hibernate3.HibernateTemplate$12.doInHibernate(HibernateTemplate.java:686) 
    org.springframework.orm.hibernate3.HibernateTemplate$12.doInHibernate(HibernateTemplate.java:1) 
    org.springframework.orm.hibernate3.HibernateTemplate.doExecute(HibernateTemplate.java:406) 
    org.springframework.orm.hibernate3.HibernateTemplate.executeWithNativeSession(HibernateTemplate.java:374) 
    org.springframework.orm.hibernate3.HibernateTemplate.save(HibernateTemplate.java:683) 
    se.hsr.daos.InfoTextDAOImpl.saveInfoText(InfoTextDAOImpl.java:26) 
    se.hsr.controllers.InfoTextController.saveInfoText(InfoTextController.java:31) 
    se.hsr.pagecontrollers.InfoTextPageController.submitForm(InfoTextPageController.java:35) 
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) 
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    java.lang.reflect.Method.invoke(Method.java:616) 
    org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:176) 
    org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:426) 
    org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:414) 
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:790) 
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719) 
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:644) 
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:560) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:637) 
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717) 

Answer 1

Nó có nghĩa là DB SQL máy chủ đang chạy ra khỏi các kết nối. Máy chủ có tham số cấu hình chỉ định mức độ tối đa cho phép kết nối.

Điều này thường chỉ ra rằng các kết nối không bị đóng. Bạn đang yêu cầu các đối tượng kết nối từ Hibernate trong mã của bạn?

Trong ngắn hạn, bạn chỉ có thể tăng kết nối tối đa cho đến khi vấn đề này được khắc phục.

Answer 2

Nếu bạn tăng số lượng kết nối có thể khắc phục được nhưng vẫn có khả năng xảy ra ngoại lệ tương tự này trong tương lai.

Đảm bảo rằng bạn đã xác định <property name="maxIdle" value="1" /> trong cấu hình cơ sở dữ liệu của mình xml tệp. Ngoài ra tôi đã có cùng một vấn đề này khi tôi xác định <property name="maxIdle" value="1" /> nó cố định vấn đề của tôi.

<bean id="myDataSource" class="org.apache.commons.dbcp.BasicDataSource" 
     destroy-method="close"> 
     <property name="driverClassName" value="com.mysql.jdbc.Driver" /> 
     <property name="url" value="jdbc:mysql://localhost/crm" /> 
     <property name="username" value="root" /> 
     <property name="password" value="root" /> 
     <property name="initialSize" value="10" /> 
     <property name="maxActive" value="15" /> 
     <property name="maxWait" value="5000" /> 
     <property name="maxIdle" value="1" /> 

    </bean> 

Answer 3

Trong Tag trên đường này là rất quan trọng

<property name="maxIdle" value="1" /> 

sẽ làm việc, vì nó sẽ cho phép chỉ có một kết nối cho AJAX hoặc theo yêu cầu DB