tomcat的log文件上的错误如何解决？

Question

我测试的时候没有问题，但是发布到服务器上后，就出现大量错误。绝大多数这两种，而且是随机的，似乎网站访问量大了，就大量报错。
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
Last packet sent to the server was 0 ms ago.
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:406)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1074)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2104)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:729)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46)
at sun.reflect.GeneratedConstructorAccessor15.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:406)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:302)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:283)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at com.machina.datalink.DBMysqlLink.getConn(DBMysqlLink.java:14)
at com.machina.dao.WebShowDAO.getShowProjects(WebShowDAO.java:19)
at org.apache.jsp.index_jsp._jspService(index_jsp.java:2120)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:849)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454)
at java.lang.Thread.run(Unknown Source)
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(Unknown Source)
at java.net.PlainSocketImpl.connectToAddress(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:256)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:276)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2027)
... 31 more
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
或者
java.lang.NullPointerException
at com.machina.dao.ParaDAO.getParaName(ParaDAO.java:20)
at com.machina.dao.SearchDAO.getShowMaProjects(SearchDAO.java:213)
at com.machina.dao.SearchDAO.getShowProjects(SearchDAO.java:526)
at org.apache.jsp.search_jsp._jspService(search_jsp.java:144)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:849)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454)
at java.lang.Thread.run(Unknown Source)
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failureLast packet sent to the server was 0 ms ago.
at sun.reflect.GeneratedConstructorAccessor19.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:406)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1074)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2104)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:729)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46)
at sun.reflect.GeneratedConstructorAccessor15.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:406)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:302)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:283)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at com.machina.datalink.DBMysqlLink.getConn(DBMysqlLink.java:14)
at com.machina.dao.ParaDAO.getParaName(ParaDAO.java:19)
at com.machina.dao.SearchDAO.getShowMaProjects(SearchDAO.java:206)
at com.machina.dao.SearchDAO.getShowProjects(SearchDAO.java:526)
at org.apache.jsp.search_jsp._jspService(search_jsp.java:144)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:374)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:849)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454)
at java.lang.Thread.run(Unknown Source)
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(Unknown Source)
at java.net.PlainSocketImpl.connectToAddress(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:256)
at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:276)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2027)
... 33 more

Answer 1

类似于 http://topic.csdn.net/u/20110815/18/D28095E6-27BB-451B-B988-D0776186F657.html 碰到的问题...

Answer 2

http://topic.csdn.net/u/20090527/13/3adff71c-7186-415c-a800-ed235500558c.html后来查出原因是，防火墙有设定，15分钟就销毁timeout连接
结贴。会是这个问题吗？不过我的时间很短很短...

Answer 3

应该没用连接池...每个函数都是这种结构...然后这些函数放在jsp里。
// 根据id查找ivtor名称
public static String findIvtorNameById(String id) {
Connection conn = null;
PreparedStatement pstmtAct = null;
ResultSet rsAct = null;
String temp = "";
// 活动
String sqlAct = "select investorName from ivt where id='" + id + "'";
try {
conn = DBMysqlLink.getConn();
pstmtAct = conn.prepareStatement(sqlAct);
rsAct = pstmtAct.executeQuery();
if (rsAct != null) {
while (rsAct.next()) {
temp = rsAct.getString("investorName");
}
} else {
System.out.println("ivtorName查找失败！");
} } catch (Exception e) {
e.printStackTrace();
} finally {
if (conn != null) {
try {
pstmtAct.close();
} catch (SQLException sx) {
sx.printStackTrace();
}
DBMysqlLink.close(conn);
}
}
return temp;
}

Answer 4

com.machina.datalink.DBMysqlLink.getConn??
这个库是你们自己写的？初步估计是这个库本身的问题。用比较能用的连接池不好吗？dbcp等等。

Answer 5

public static Connection getConn() {
Connection conn = null;
try {
Class.forName("com.mysql.jdbc.Driver");

//  测试环境
 conn = DriverManager.getConnection("jdbc:mysql://localhost/aaa?user=aa&password=aa");

} catch (ClassNotFoundException e) {
e.printStackTrace();
System.out.println("DBMysqlLink的connection出错。");
} catch (SQLException e) {
e.printStackTrace();
} return conn;
}