java 如何解决异常“com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException：数据源拒绝建立连接”？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/25600907/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
How to resolve the Exception “com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Data source rejected establishment of connection”?
提问by Raghu
my application uses Hibernate. I am working on an ITS(Intelligent Transport System) So here every 10 seconds I have track the position(latitude, longitude) of bus. I call a ajax method every 10 sec which makes request to servlet. My application works fine for some time period, after that it shows error as ,
我的应用程序使用 Hibernate。我正在研究 ITS（智能交通系统），所以这里每 10 秒我就跟踪一次公交车的位置（纬度、经度）。我每 10 秒调用一个 ajax 方法，它向 servlet 发出请求。我的应用程序在一段时间内工作正常，之后它显示错误，
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
and
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)
I am not getting how to resolve it. I searched many resource and found that it is about managing connection pool in hibernate configuration file.
我不知道如何解决它。我搜索了很多资源，发现它是关于在休眠配置文件中管理连接池的。
So here is my Hiberenate configuration file.
所以这是我的 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 -->
Can any one tell me what are the changes I have to do and why?
谁能告诉我我必须做哪些改变，为什么？
回答by mp911de
The server responds with "Too many connections"
服务器响应“连接过多”
- Increase the max connection count (and make sure that unused connections are closed/use pooling)
- Check active connections on the server using http://dev.mysql.com/doc/refman/5.5/en/show-processlist.html
- 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检查服务器上的活动连接
See http://dev.mysql.com/doc/refman/5.5/en/too-many-connections.html
见http://dev.mysql.com/doc/refman/5.5/en/too-many-connections.html
回答by zatenzu
Make sure that you close correctly your session in the end of your method process in your Servlet.
确保在 Servlet 中的方法进程结束时正确关闭会话。
