用户数据较大导致内存溢出等异常

注册用户有3000个左右，我在后台域管理中查看用户列表或修改、新增用户时速度非常慢，而且后台报错：
[ERROR]_2011-08-08 15:23:02 :Caught an Ognl exception while getting property _departmentlist
   ognl.OgnlException: _departmentlist [java.lang.OutOfMemoryError: Java heap space]
        at ognl.OgnlRuntime.getMethodValue(OgnlRuntime.java:908)
        at ognl.ObjectPropertyAccessor.getPossibleProperty(ObjectPropertyAccessor.java:54)
        at ognl.ObjectPropertyAccessor.getProperty(ObjectPropertyAccessor.java:122)
        at com.opensymphony.xwork.util.OgnlValueStack$ObjectAccessor.getProperty(OgnlValueStack.java:53)
        at ognl.OgnlRuntime.getProperty(OgnlRuntime.java:1616)
        at com.opensymphony.xwork.util.CompoundRootAccessor.getProperty(CompoundRootAccessor.java:102)
        at ognl.OgnlRuntime.getProperty(OgnlRuntime.java:1616)
        at ognl.ASTProperty.getValueBody(ASTProperty.java:96)
        at ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:170)
        at ognl.SimpleNode.getValue(SimpleNode.java:210)
        at ognl.Ognl.getValue(Ognl.java:333)
        at ognl.Ognl.getValue(Ognl.java:310)
        。。。。。。。。。。。。。。。。。。。。。。。。中间省略
/-- Encapsulated exception ------------\
java.lang.OutOfMemoryError: Java heap space
        at java.util.Arrays.copyOf(Arrays.java:2882)
        at java.lang.AbstractStringBuilder.expandCapacity(AbstractStringBuilder.java:100)
        at java.lang.AbstractStringBuilder.append(AbstractStringBuilder.java:390)
        at java.lang.StringBuffer.append(StringBuffer.java:224)
        at org.hibernate.impl.SessionImpl.toString(SessionImpl.java:1802)
        at java.lang.String.valueOf(String.java:2827)
        at java.lang.StringBuilder.append(StringBuilder.java:115)
        at cn.myapps.base.dao.HibernateBaseDAO.currentSession(HibernateBaseDAO.java:703)
                。。。。。。。。。。。。。。。。。。。。。。。中间省略

[ERROR]_2011-08-08 15:23:40 :Caught an Ognl exception while getting property reportTree
   ognl.OgnlException: reportTree [org.hibernate.exception.GenericJDBCException: could not inspect JDBC autocommit mode]
        at ognl.OgnlRuntime.getMethodValue(OgnlRuntime.java:908)
        at ognl.ObjectPropertyAccessor.getPossibleProperty(ObjectPropertyAccessor.java:54)
        at ognl.ObjectPropertyAccessor.getProperty(ObjectPropertyAccessor.java:122)
        at com.opensymphony.xwork.util.OgnlValueStack$ObjectAccessor.getProperty(OgnlValueStack.java:53)
                。。。。。。。。。。。。。。。。。。。。。。。。中间省略
/-- Encapsulated exception ------------\
org.hibernate.exception.GenericJDBCException: could not inspect JDBC autocommit mode
        at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:103)
        at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:91)
        at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
        at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:29)
        at org.hibernate.jdbc.JDBCContext.afterNontransactionalQuery(JDBCContext.java:248)
        at org.hibernate.impl.SessionImpl.afterOperation(SessionImpl.java:417)
        at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1126)
        at ognl.OgnlRuntime.getProperty(OgnlRuntime.java:1616)
        at com.opensymphony.xwork.util.CompoundRootAccessor.getProperty(CompoundRootAccessor.java:102)
        at ognl.OgnlRuntime.getProperty(OgnlRuntime.java:1616)
        at ognl.ASTProperty.getValueBody(ASTProperty.java:96)
        at ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:170)
        at ognl.SimpleNode.getValue(SimpleNode.java:210)
        at ognl.Ognl.getValue(Ognl.java:333)
        at ognl.Ognl.getValue(Ognl.java:310)
                。。。。。。。。。。。。。。。。。中间省略
Caused by: java.sql.SQLException: Invalid state, the Connection object is closed.
        at net.sourceforge.jtds.jdbc.ConnectionJDBC2.checkOpen(ConnectionJDBC2.java:1634)
        at net.sourceforge.jtds.jdbc.ConnectionJDBC2.getAutoCommit(ConnectionJDBC2.java:2050)
        at sun.reflect.GeneratedMethodAccessor70.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)

这是tomcat日志报的一连串的错误，网上查了一下，说是连接池的问题，有没谁遇到过相似的问题，急啊。。。。。。。。。。。。。。。。

您好，您把连接池的大小设置大一些看一下。

谢谢，我测试一下看。