Web工程出现错误mysql错误

Question

我放了一个Java的Web工程到一个美国的主机，数据库用的是mysql，但有时候出现访问错误
下面是后台日志
com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception: ** BEGIN NESTED EXCEPTION ** java.io.EOFExceptionSTACKTRACE:java.io.EOFException
at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:1865)
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2256)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2756)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1536)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1626)
at com.mysql.jdbc.Connection.execSQL(Connection.java:3031)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:943)
at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1049)
at dbmanager.DBManager.ExcuteQueryBySql(DBManager.java:251)
at dao.ProductDao.SelectProductType(ProductDao.java:159)
at org.apache.jsp.ProductShow.ProductDetail_jsp._jspService(ProductDetail_jsp.java:77)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:332)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
at java.lang.Thread.run(Thread.java:595)
** END NESTED EXCEPTION **Last packet sent to the server was 15 ms ago.
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2467)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2756)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1536)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1626)
at com.mysql.jdbc.Connection.execSQL(Connection.java:3031)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:943)
at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:1049)
at dbmanager.DBManager.ExcuteQueryBySql(DBManager.java:251)
at dao.ProductDao.SelectProductType(ProductDao.java:159)
at org.apache.jsp.ProductShow.ProductDetail_jsp._jspService(ProductDetail_jsp.java:77)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:332)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
at java.lang.Thread.run(Thread.java:595)
2009-9-13 22:23:50 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet jsp threw exception
java.lang.NullPointerException
at dao.ProductDao.SelectProductType(ProductDao.java:162)
at org.apache.jsp.ProductShow.ProductDetail_jsp._jspService(ProductDetail_jsp.java:77)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:97)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:332)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:314)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:264)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
at java.lang.Thread.run(Thread.java:595)有人给予解答下不

Answer 1

Communications link failure估计是连不上数据库造成的，通过客户端可以连上吗，如果不行应该是权限的问题如果客户端可以连，检查一下连接数据库的字符串是否有写错

Answer 2

to sgtzzc
出现这个问题后，如果在界面上再刷新一下 或者按F5就又可以了。
所以说连不上数据 这个也不是这样说的应该。to ACMAIN_CHM
权限问题应该不是。如上。
连接方式是编码。如下： private static final String DRIVER_CLASS = "com.mysql.jdbc.Driver";
private static final String DATABASE_URL = "jdbc:mysql://American mysql server:3306/database name";
private static Connection conn = null;
public static Connection getConnection()
{
try {
Class.forName(DRIVER_CLASS);
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} try {
conn=DriverManager.getConnection(DATABASE_URL,username,password);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return  conn;
}
以及其中一个数据库操作函数
public static ResultSet ExcuteQuery(String sql)
{
ResultSet rs=null;
PreparedStatement pStat=null;
try {
boolean flag = false;
if (conn == null) {
            flag = true;
        }
        if (conn != null) {
            if (conn.isClosed()) {
                flag = true;
            }
        }
        if (flag) {
         conn=DBManager.getConnection();
        }
pStat=conn.prepareStatement(sql);
rs=pStat.executeQuery();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally{

}
return rs;
}

Answer 3

用的mysql驱动是mysql-connector-java-5.0.0-beta-bin.jar

Answer 4

private static final String DATABASE_URL = "jdbc:mysql://American mysql server:3306/database name"; 这句是你贴出来的时候改的还是你的代码本身就是这样写的？如果代码是这样的话就要改一下了，American mysql server换成数据库主机IP,database name换成数据库名称。

Answer 5

调大 max_allowed_packet        

Answer 6

to zhoupuyue
明显这个实际不是这样写的。to nianzhang747
可以写个如何调大的code不
谢了先啊

Answer 7

mysql> show variables like "max_allowed_packet"
    -> ;
+--------------------+---------+
| Variable_name      | Value   |
+--------------------+---------+
| max_allowed_packet | 1048576 |
+--------------------+---------+
1 row in set (0.00 sec)
mysql> set global max_allowed_packet=2048576        ;
Query OK, 0 rows affected (0.00 sec)

Answer 8

to nianzhang747 
我的mysql服务器在美国那边
不然本地的话 我都是没有问题的。

Answer 9

刚才问了美国那的技术支持
他们说他们的数据库连接的idle time是60s
当连接idle了，如果重新获得一个连接呢？

Answer 10

to nianzhang747
就是在页面上停留超过60s，再去连接数据库的时候，连接就断了。
就出现上面那个错误了。 public static ResultSet ExcuteQueryBySql(String sql,Object Product[])
    {
     ResultSet rs=null;
     //Connection conn=DBManager.getConnection();
PreparedStatement pStat=null;
try {
boolean flag = false;
if (conn == null) {
            flag = true;
        }
        if (conn != null) {
            if (conn.isClosed()) {
                flag = true;
            }
        }
        if (flag) {
         conn=DBManager.getConnection();
        }
pStat=conn.prepareStatement(sql);
for(int i=0;i<Product.length;i++)
{
pStat.setObject(i+1, Product[i]);
}
rs=pStat.executeQuery();
if(null==rs){
System.out.println("rs is null");
}
}catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally{
//CloseConnection(conn,pStat);
}
     return rs;
    
    }像上面这个函数
pStat=conn.prepareStatement(sql); //这行代码还是过的
rs=pStat.executeQuery();  //这行出错了

Answer 11

finally{ 
//CloseConnection(conn,pStat); 
} 
    return rs; 
    
    } 
------------------
为什么关闭链接注释掉了

Answer 12

to nianzhang747
不关闭注释的话 出现这个结果
2009-9-15 15:53:48 org.apache.catalina.core.StandardContext reload
信息: Reloading this Context has started
java.sql.SQLException: Operation not allowed after ResultSet closed
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:910)
at com.mysql.jdbc.ResultSet.checkClosed(ResultSet.java:641)
at com.mysql.jdbc.ResultSet.next(ResultSet.java:6437)
at dao.ImageDao.getImageInfo(ImageDao.java:65)
at dao.ProductDao.SelectProductWithImage(ProductDao.java:99)
at org.apache.jsp.Index_jsp._jspService(Index_jsp.java:59)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:875)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
at java.lang.Thread.run(Unknown Source)
java.sql.SQLException: Operation not allowed after ResultSet closed
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:910)
at com.mysql.jdbc.ResultSet.checkClosed(ResultSet.java:641)
at com.mysql.jdbc.ResultSet.checkRowPos(ResultSet.java:679)
at com.mysql.jdbc.ResultSet.getNativeString(ResultSet.java:4218)
at com.mysql.jdbc.ResultSet.getStringInternal(ResultSet.java:5428)
at com.mysql.jdbc.ResultSet.getString(ResultSet.java:5240)
at dao.ProductDao.SelectProductWithImage(ProductDao.java:101)
at org.apache.jsp.Index_jsp._jspService(Index_jsp.java:59)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:875)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
at java.lang.Thread.run(Unknown Source)
java.sql.SQLException: Operation not allowed after ResultSet closed
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:910)
at com.mysql.jdbc.ResultSet.checkClosed(ResultSet.java:641)
at com.mysql.jdbc.ResultSet.next(ResultSet.java:6437)
at dao.ProductDao.GetProductTypeNumber(ProductDao.java:341)
at org.apache.jsp.Index_jsp._jspService(Index_jsp.java:65)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:875)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
at java.lang.Thread.run(Unknown Source)
java.sql.SQLException: Operation not allowed after ResultSet closed
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:910)
at com.mysql.jdbc.ResultSet.checkClosed(ResultSet.java:641)
at com.mysql.jdbc.ResultSet.next(ResultSet.java:6437)
at dao.ProductDao.GetProductTypeLeadNumber(ProductDao.java:378)
at org.apache.jsp.Index_jsp._jspService(Index_jsp.java:72)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:875)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
at java.lang.Thread.run(Unknown Source)而且数据取不出来。难道你写一个数据库操作函数 去取ResultSet的时候 把conn和pStat关闭的？

Answer 13

之所以没有关闭ResultSet。
因为ResultSet要作为参数传递下去