从「；“堆内存”；至；java.sql.SQLException:结果集关闭后不允许操作"；

我有一个小网站，从mysql数据库（BLOB字段）获取图片，然后将它们打印到我的网页上

我用一些类读取blob字段，将它们剪切成“方形”图片，然后用servlet将图片打印到页面上

在每一页我都这样做（读一些blob字段，剪切图片，打印大约10张图片）

我在租用的服务器上有自己的虚拟机，我有64MB的堆空间

有时，我会出现这样的错误：

"Exception in thread "http-bio-12418-exec-26" java.lang.OutOfMemoryError: Java heap space"

所以，我觉得我的代码太“重”，就编辑了它。现在，我不时在tomcat日志中看到这个错误：

    Feb 10, 2014 7:23:11 AM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [jsp] in context with path [] threw exception [javax.servlet.ServletException: java.sql.SQLException: Operation not allowed after ResultSet closed] with root cause
java.sql.SQLException: Operation not allowed after ResultSet closed
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1073)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:987)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:982)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:927)
    at com.mysql.jdbc.ResultSetImpl.checkClosed(ResultSetImpl.java:794)
    at com.mysql.jdbc.ResultSetImpl.next(ResultSetImpl.java:7139)
    at org.apache.jsp.NewsDinamic_jsp._jspService(NewsDinamic_jsp.java:104)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1041)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:603)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:662)
Feb 10, 2014 7:25:42 AM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [jsp] in context with path [] threw exception [javax.servlet.ServletException: java.sql.SQLException: Operation not allowed after ResultSet closed] with root cause
java.sql.SQLException: Operation not allowed after ResultSet closed
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1073)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:987)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:982)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:927)
    at com.mysql.jdbc.ResultSetImpl.checkClosed(ResultSetImpl.java:794)
    at com.mysql.jdbc.ResultSetImpl.next(ResultSetImpl.java:7139)
    at org.apache.jsp.News_jsp._jspService(News_jsp.java:174)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1041)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:603)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:662)

但这个错误毫无意义。我确信问题不在于数据库！如果我刷新页面，那么该网站将保持良好的工作状态。我肯定我必须在服务器上做些什么

---

注意：我从我的站点的lib文件夹中删除了JDBC库和我添加到porject中的所有其他库，并按照本论坛的一些建议将它们放在tomcat lib文件夹中。

我认为您的问题在于堆大小，因此首先需要查看JVM内存参数。实际上，您可以为JVM设置任意多的内存：

-Xmx2048m -> this param to set the max memory that the JVM can allocate
-Xms1024m -> the init memory that JVM will allocate on the start up
-XX:MaxPermSize=512M -> this for the max Permanent Generation memory
-XX:MaxNewSize=  -> this need to be 40% from your Xmx value
-XX:NewSize=614m -> this need to be 40% from your Xmx value

---

因此，首先确保您正确设置了此参数，然后如果您仍然收到

OutOfMemoryError

您可能正在关闭连接，请编辑您的代码，然后尝试使用resultset，发布相关代码，以便我们可以看到您在做什么。显示您的代码，尤其是在resultset.close（）之后@fatman我添加了错误trackstacktrace，这很好，但是我们需要实际的java代码，我怎么能做到呢？jvm位于我租用的服务器上。我应该编辑tomcat/bin/catalina.sh吗？是的，将它们添加到

catalina_OPTS

下，例如：

catalina_OPTS=“-Xmx2048m-Xms1024m”

已经有这行catalina_OPTS=“$catalina_OPTS$JPDA_OPTS”。我应该删除它吗？只是添加一个新行吗？不，不要删除任何内容，只需确保您要查找的行是

export CATALINA_OPTS=“Arguments”

，然后在已经存在的任何内容旁边添加参数。我将这一行CATALINA_OPTS=“$CATALINA_OPTS$JPDA_OPTS”转换为这一行CATALINA_OPTS=“$CATALINA_OPTS$JPDA_OPTS–Xmx2048m-Xms1024m”。但我仍然得到相同的错误。我只是在服务器上得到这个错误，当我在我的计算机上测试站点时，它是完美的！