Question

我的简单网络应用有时会在浏览网站时崩溃，我从日志中获得的错误消息可以在下面找到。我完全不知道造成这种情况的原因，并且非常感谢能够引导我走向正确方向的任何提示。

HTTP Status 500 - org.hibernate.exception.JDBCConnectionException: Cannot open connection

输入例外报告

message org.hibernate.exception.JDBCConnectionException: Cannot open connection

description The server encountered an internal error that prevented it from fulfilling this request.

exception
org.apache.jasper.JasperException: org.hibernate.exception.JDBCConnectionException: Cannot open connection
    org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:549)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:470)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:728)

根本原因

org.hibernate.exception.JDBCConnectionException: Cannot open connection
    org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:97)
    org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
    org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:52)
    org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:449)
    org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:167)
    org.hibernate.jdbc.AbstractBatcher.prepareQueryStatement(AbstractBatcher.java:161)
    org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1573)
    org.hibernate.loader.Loader.doQuery(Loader.java:696)
    org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259)
    org.hibernate.loader.Loader.doList(Loader.java:2228)
    org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2125)
    org.hibernate.loader.Loader.list(Loader.java:2120)
    org.hibernate.loader.criteria.CriteriaLoader.list(CriteriaLoader.java:118)
    org.hibernate.impl.SessionImpl.list(SessionImpl.java:1596)
    org.hibernate.impl.CriteriaImpl.list(CriteriaImpl.java:306)
    com.html.XmlSetting.getListOfhtml_connect(XmlSetting.java:55)
    com.html.XmlSetting.removeXml(XmlSetting.java:121)
    com.html.MarginSetting.removeXml(MarginSetting.java:291)
    org.apache.jsp.check_jsp._jspService(check_jsp.java:183)
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:728)

根本原因

com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Too many connections
    sun.reflect.GeneratedConstructorAccessor153.newInstance(Unknown Source)
    sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    java.lang.reflect.Constructor.newInstance(Constructor.java:532)
    com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
    com.mysql.jdbc.Util.getInstance(Util.java:381)
    com.mysql.jdbc.SQLError.createSQLException(SQLError.java:985)
    com.mysql.jdbc.SQLError.createSQLException(SQLError.java:957)
    com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3376)
    com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3308)
    com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:894)
    com.mysql.jdbc.MysqlIO.secureAuth411(MysqlIO.java:3808)
    com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1256)
    com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2032)
    com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:729)
    com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46)
    sun.reflect.GeneratedConstructorAccessor145.newInstance(Unknown Source)
    sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    java.lang.reflect.Constructor.newInstance(Constructor.java:532)
    com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
    com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:302)
    com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:283)
    java.sql.DriverManager.getConnection(DriverManager.java:620)
    java.sql.DriverManager.getConnection(DriverManager.java:169)
    org.hibernate.connection.DriverManagerConnectionProvider.getConnection(DriverManagerConnectionProvider.java:133)
    org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:446)
    org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:167)
    org.hibernate.jdbc.AbstractBatcher.prepareQueryStatement(AbstractBatcher.java:161)
    org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1573)
    org.hibernate.loader.Loader.doQuery(Loader.java:696)
    org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259)
    org.hibernate.loader.Loader.doList(Loader.java:2228)
    org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2125)
    org.hibernate.loader.Loader.list(Loader.java:2120)
    org.hibernate.loader.criteria.CriteriaLoader.list(CriteriaLoader.java:118)
    org.hibernate.impl.SessionImpl.list(SessionImpl.java:1596)
    org.hibernate.impl.CriteriaImpl.list(CriteriaImpl.java:306)
    com.html.XmlSetting.getListOfhtml_connect(XmlSetting.java:55)
    com.html.XmlSetting.removeXml(XmlSetting.java:121)
    com.html.MarginSetting.removeXml(MarginSetting.java:291)
    org.apache.jsp.check_jsp._jspService(check_jsp.java:183)
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:728)

我正在使用Apache Tomcat 7

hibernate.cfg.xml中

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>

        <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/htmlcleaner</property>
        <property name="hibernate.connection.password">root</property>
        <property name="hibernate.connection.username">root</property>

        <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
        <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
        <property name="hibernate.connection.zeroDateTimeBehavior">convertToNull</property>

        <property name="connection.pool_size">1000</property>

       <!--  <property name="show_sql">true</property> -->
        <mapping class="com.model.html_connect"/>

    </session-factory>
</hibernate-configuration>

Answer 1

它清楚地看到hibernate无法创建或打开与数据库的连接，可能有很多原因它们是

使用会话
连接池很小，有太多线程正在访问池。

请粘贴您的配置和例外点程序

添加

<property name="hibernate.connection.release_mode">on_close</property>

属性并调用session.close（）;在你的方法结束时

Answer 2

可能的原因是您的Web应用程序可能正在泄漏连接，或者连接池大小非常小，因为当前正在使用所有打开的连接并且无法获得新连接。

我不确定Tomcat，但在JBoss中，我们通常会引用数据源文件，您可以将连接池大小设置为

   <max-pool-size>80</max-pool-size>

您甚至可以登录Tomcat的管理控制台，并在收到此异常时检查实际使用的连接数。管理控制台将为您提供有史以来创建的最大连接对象以及与连接池相关的各种其他信息。

Answer 3

看起来你正在大量泄漏连接。你完成后会关闭你的休眠会话吗？

您还可以尝试使用hibernate.connection.release_mode进行操作，默认情况下，将其设置为auto，并在关闭会话时释放连接。但是，您也可以使用after_transaction或after_statement选项（当它为两者中的每一个释放连接时，它会非常自我解释：P）。

尽管如此，你确实需要找出你泄漏的地方:)

com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException：连接太多

3 个答案: