Com. MySQL. JDBC. Exceptions. jdbc4.communicationsexception: communications link failure, caused byno B

The following error occurs when data is inserted into MySQL using Java (tens of millions of records, which takes a long time:

Com. MySQL. JDBC. Exceptions. jdbc4.communicationsexception: communications link failure

Last packet sent to the server was 0 MS ago.


At sun. Reflect. generatedconstructoraccessor10.newinstance (unknown source)
At sun. Reflect. delegatingconstruct%cessorimpl. newinstance (delegatingconstruct%cessorimpl. 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. generatedconstructoraccessor8.newinstance (unknown source)
At sun. Reflect. delegatingconstruct%cessorimpl. newinstance (delegatingconstruct%cessorimpl. 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: 185)
At decompress. decompressview. jbutton2actionreceivmed (decompressview. Java: 734)
At decompress. decompressview. Access $1400 (decompressview. Java: 43)
At decompress. decompressview $7. actionreceivmed (decompressview. Java: 416)
At javax. Swing. abstractbutton. fireactionshortmed (abstractbutton. Java: 1995)
At javax. Swing. Sort actbutton $ handler. actionshortmed (export actbutton. Java: 2318)
At javax. Swing. defaultbuttonmodel. fireactionreceivmed (defaultbuttonmodel. Java: 387)
At javax. Swing. defaultbuttonmodel. setpressed (defaultbuttonmodel. Java: 242)
At javax. Swing. plaf. Basic. basicbuttonlistener. mousereleased (basicbuttonlistener. Java: 236)
At java. AWT. component. processmouseevent (component. Java: 6263)
At javax. Swing. jcomponent. processmouseevent (jcomponent. Java: 3267)
At java. AWT. component. processevent (component. Java: 6028)
At java. AWT. Container. processevent (container. Java: 2041)
At java. AWT. component. dispatcheventimpl (component. Java: 4630)
At java. AWT. Container. dispatcheventimpl (container. Java: 2099)
At java. AWT. component. dispatchevent (component. Java: 4460)
At java. AWT. lightweightdispatcher. retargetmouseevent (container. Java: 4574)
At java. AWT. lightweightdispatcher. processmouseevent (container. Java: 4238)
At java. AWT. lightweightdispatcher. dispatchevent (container. Java: 4168)
At java. AWT. Container. dispatcheventimpl (container. Java: 2085)
At java. AWT. Window. dispatcheventimpl (window. Java: 2478)
At java. AWT. component. dispatchevent (component. Java: 4460)
At java. AWT. eventqueue. dispatchevent (eventqueue. Java: 599)
At java. AWT. eventdispatchthread. pumponeeventforfilters (eventdispatchthread. Java: 269)
At java. AWT. eventdispatchthread. pumpeventsforfilter (eventdispatchthread. Java: 184)
At java. AWT. eventdispatchthread. pumpeventsforhierarchy (eventdispatchthread. Java: 174)
At java. AWT. eventdispatchthread. pumpevents (eventdispatchthread. Java: 169)
At java. AWT. eventdispatchthread. pumpevents (eventdispatchthread. Java: 161)
At java. AWT. eventdispatchthread. Run (eventdispatchthread. Java: 122)
Caused by: java.net. socketexception: no buffer space available (maximum connections reached ?) : Connect

Judging from the red text,

It should be the maximum number of connections. I have been searching online for a long time and have the same symptoms, but the problem is caused by timeout, and their solutions fail to solve my problem.

I think I should start with solving the maximum number of links. Finally, my code is modified as follows to solve the problem:

String url = "JDBC: mysql: // localhost/weblog ";
String user = "root ";
String Password = "";
Class. forname ("com. MySQL. JDBC. Driver ");
Connection conn = drivermanager. getconnection (URL, user, password );
Statement STM = conn. createstatement ();

While (line! = NULL)
{

.......
String insql = "insert into Log Values (null, '" + ipaddr + "', null )";
Try
{
Cmd.exe cute (insql );
}
Catch (sqlexception E)
{
E. printstacktrace ();
}
} // End while
STM. Close ();
Conn. Close ();
}
The original cause is that

Connection conn = drivemanager. getconnection (URL, user, password );

Statement STM = conn. createstatement ();

Written in the while loop, and no

STM. Close ()

Conn. Close. Of course there will be problems.

Later, I added two sentences to close the connection in the WHILE LOOP, but the same problem still exists.

Later, the conn and STM statements and the closed statements are all placed outside the while clause.

 

The problem with the same symptoms on the internet is caused by timeout. The solution is as follows:

Http://blog.csdn.net/leizhendong/archive/2007/04/16/1566484.aspx

Http://www.wangzhongyuan.com/archives/610.html

Http://www.svn8.com/mysql/200906036013.html