java无法连接到mysql数据库

ggf34567

网站不定期出现，连接不到mysql数据库的状况，重启服务器后可自动恢复，不知是啥问题，以下是日志，大家帮分析下是什么问题？
2012-8-23 0:00:18 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet jsp threw exception
java.sql.SQLException: Duplicate entry ':kuk:FOREIGN:vzg:1' for key 1
        at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:292
        at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1571)
        at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1666)
        at com.mysql.jdbc.Connection.execSQL(Connection.java:298
        at com.mysql.jdbc.Connection.execSQL(Connection.java:2917)
        at com.mysql.jdbc.Statement.executeQuery(Statement.java:824)
        at org.apache.tomcat.dbcp.dbcp.DelegatingStatement.executeQuery(DelegatingStatement.java:20
        at com.web.db.Database.query(Database.java:53)
        at org.apache.jsp.xiangyu.newslist_jsp._jspService(newslist_jsp.java:317)
        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.tuckey.web.filters.urlrewrite.UrlRewriteFilter.doFilter(UrlRewriteFilter.java:73
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at com.web.filter.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:117)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
        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:12
        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:286)
        at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:845)
        at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
        at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
        at java.lang.Thread.run(Thread.java:595)

dyllove98

数据库链接经常闲置吗？有没有可能是闲置的时间过长 mysql自动断开了呀