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When the client connects to MySQL, it throws the below exception

Last packet sent to the server was 0 ms ago.
        at sun.reflect.GeneratedConstructorAccessor112.newInstance(Unknown Source)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
        at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
        at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1074)
        at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2103)
        at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:718)
        at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46)
        at sun.reflect.GeneratedConstructorAccessor110.newInstance(Unknown Source)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
        at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
        at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:302)
        at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:282)
        at java.sql.DriverManager.getConnection(DriverManager.java:582)
        at java.sql.DriverManager.getConnection(DriverManager.java:154)
        at org.logicalcobwebs.proxool.DefaultConnectionBuilder.buildConnection(DefaultConnectionBuilder.java:39)
        at org.logicalcobwebs.proxool.Prototyper.buildConnection(Prototyper.java:159)
        at org.logicalcobwebs.proxool.ConnectionPool.getConnection(ConnectionPool.java:211)
        at org.logicalcobwebs.proxool.ProxoolDriver.connect(ProxoolDriver.java:89)
        at java.sql.DriverManager.getConnection(DriverManager.java:582)
        at java.sql.DriverManager.getConnection(DriverManager.java:207)
        at com.chinaren.tools.MysqlConnectionPools.getConnection(MysqlConnectionPools.java:652)
        ..........
Caused by: java.net.ConnectException: Connection refused
        at java.net.PlainSocketImpl.socketConnect(Native Method)
        at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
        at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
        at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
        at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
        at java.net.Socket.connect(Socket.java:525)
        at java.net.Socket.connect(Socket.java:475)
        at java.net.Socket.<init>(Socket.java:372)
        at java.net.Socket.<init>(Socket.java:215)
        at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:253)
        at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:280)
        at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2026)
        ... 51 more
  1. the client can ping dbServer is OK
  2. the client can telnet dbServer:port is OK
  3. the same code on my computer connection to dbServer is OK

Is this the 8 hours problem? What is the cause?

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  • What is it about 8 hours that you mentioned? Commented Jul 12, 2012 at 13:20
  • @Olaf a connection is idle 8 hours(default),MySQL Server will kill the connection Commented Jul 24, 2012 at 10:10

1 Answer 1

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2

java.net.ConnectException: Connection refused: The connection is refused. This happens on a low level and means that the port is not open or the connection is actively refused by a firewall. Check if the JDBC URL and/or DataSource configuration actually uses the hostname/IP and port that it should use.

Also is the client actually pinging and telnetting from the same computer as this application is running on?

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1 Comment

@Rotteveel yes,on same computer!

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