java - 如何解决异常 “com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Data source rejected establishment of connection”？

Question

我的应用程序使用 Hibernate。我在 ITS(智能交通系统)上工作，所以我每 10 秒跟踪一次公交车的位置(纬度、经度)。我每 10 秒调用一次 ajax 方法，它向 servlet 发出请求。我的应用程序在一段时间内运行良好，之后显示错误，

org.hibernate.exception.JDBCConnectionException: Cannot open connection
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:99)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:52)
at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:449)
at org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:167)
at org.hibernate.jdbc.JDBCContext.connection(JDBCContext.java:160)
at org.hibernate.transaction.JDBCTransaction.begin(JDBCTransaction.java:81)
at org.hibernate.impl.SessionImpl.beginTransaction(SessionImpl.java:1473)
at 

和

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:411)
at com.mysql.jdbc.Util.getInstance(Util.java:386)

我不知道如何解决它。我搜索了很多资源，发现它是关于在 hibernate 配置文件中管理连接池的。

这是我的 Hiberenate 配置文件。

<hibernate-configuration>
<session-factory>
<!-- Database connection settings -->
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://localhost:3306/bus_serverdb</property>
<property name="connection.username">root</property>
<property name="connection.password">root</property>

<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>

<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>

<!-- Disable the second-level cache  -->
<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>

<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>

<!-- Drop and re-create the database schema on startup -->
<!-- <property name="hbm2ddl.auto">create</property> -->

<!-- Names the annotated entity class -->

谁能告诉我我必须做哪些更改以及为什么？

Answer 1

服务器响应“连接太多”

• 增加最大连接数(并确保关闭未使用的连接/使用池)
• 使用 http://dev.mysql.com/doc/refman/5.5/en/show-processlist.html 检查服务器上的 Activity 连接

参见 http://dev.mysql.com/doc/refman/5.5/en/too-many-connections.html