数据库 com.microsoft.sqlserver.jdbc.SQLServerException: 该连接已关闭。

[younerest]

今天在做一数据库操作的时候出现了点问题，请大侠们指教下。
当程序执行到绿色行代码的时候，出现

com.microsoft.sqlserver.jdbc.SQLServerException: 该连接已关闭。
at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDriverError(Unknown Source)
at com.microsoft.sqlserver.jdbc.SQLServerConnection.checkClosed(Unknown Source)
at com.microsoft.sqlserver.jdbc.SQLServerStatement.checkClosed(Unknown Source)
at com.microsoft.sqlserver.jdbc.SQLServerResultSet.checkClosed(Unknown Source)
at com.microsoft.sqlserver.jdbc.SQLServerResultSet.findColumn(Unknown Source)
at com.microsoft.sqlserver.jdbc.SQLServerResultSet.getInt(Unknown Source)
at wyrc.getType(wyrc.java:327)
at wyrc.doGet(wyrc.java:106)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:198)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:152)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:137)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:118)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:102)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683)
at java.lang.Thread.run(Thread.java:619)

相关的代码如下：

public TypeEntity getType(int typeId) {
TypeEntity entity = null;
String sql = "select * from kidefet where dxlbid ="+typeId;
ResultSet rs=null;
try {
rs=LookForResultSet(sql);
rs.last();
if(rs.getRow()>0)
{
rs.beforeFirst();
while (rs.next()) {
entity = new TypeEntity();
entity.setTypeId(typeId);
entity.setTypeName(rs.getString("lbmc"));
entity.setYdId(rs.getInt("tyglejk"));
entity.setYdName(getChannelName(rs.getInt("wergltjk")));
错误提示的wyrc.getType(wyrc.java:327)行entity.setLtId(rs.getInt("kfgljttrklt")); entity.setLtName(getChannelName(rs.getInt("uygljklt")));
entity.setDxId(rs.getInt("mhgldxjk"));
entity.setDxName(getChannelName(rs.getInt("fghgls")));
entity.setXltId(rs.getInt("rweljkxlt"));
entity.setXltName(getChannelName(rs.getInt("ogljolt")));
entity.setBmdId(rs.getInt("iglbuy"));
entity.setBmdName(getChannelName(rs.getInt("aglbv")));
break;
}
}
rs.getStatement().close();
rs.close();
} catch (Exception e) {
e.printStackTrace();
}
return entity;
}


public String getChannelName(int channelId) {
String result = null;
String sql = "select zhglbt from hefeisms.uiesder where uieslid ="+channelId;
try {
ResultSet rs = LookForResultSet(sql);
rs.last();
if(rs.getRow()!=0)
{
rs.beforeFirst();
while (rs.next()) {
result = rs.getString("zhglbt");
break;
}
}
rs.getStatement().close();
rs.close();
} catch (Exception e) {
e.printStackTrace();
}
System.out.println(result);
return result;
}





public ResultSet LookForResultSet(String sqltext)
{
Connection conn=null;
ResultSet rst=null;
try{
conn=connPool.getConnection();//从连接池获取Connection
Statement stm=null;
stm=conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
rst=stm.executeQuery(sqltext);
}catch(Exception e)
{
e.printStackTrace();
}
connPool.returnConnection(conn);
return rst;
}


请大虾们帮忙看看

[younerest]

代码重新编辑下：

public TypeEntity getType(int typeId）{
TypeEntity entity = null;
String sql = "select * from kidefet where dxlbid ="+typeId;
ResultSet rs=null;
try {
rs=LookForResultSet(sql);
rs.last();
if(rs.getRow()>0)
{
rs.beforeFirst();
while (rs.next()) {
entity = new TypeEntity();
。。。。。。。
entity.setYdName(getChannelName(rs.getInt("wergltjk")));
错误提示的wyrc.getType(wyrc.java:327)行
entity.setLtId(rs.getInt("kfgljttrklt"));
entity.setLtName(getChannelName(rs.getInt("uygljklt")));
entity.setDxId(rs.getInt("mhgldxjk"));
。。。。。。。
break;
}
}
rs.getStatement().close();
rs.close();
} catch (Exception e) {
e.printStackTrace();
}
return entity;
}


public String getChannelName(int channelId) {
String result = null;
String sql = "select zhglbt from hefeisms.uiesder where uieslid ="+channelId;
try {
ResultSet rs = LookForResultSet(sql);
rs.last();
if(rs.getRow()!=0)
{
rs.beforeFirst();
while (rs.next()) {
result = rs.getString("zhglbt");
break;
}
}
rs.getStatement().close();
rs.close();
} catch (Exception e) {
e.printStackTrace();
}
System.out.println(result);
return result;
}





public ResultSet LookForResultSet(String sqltext)
{
Connection conn=null;
ResultSet rst=null;
try{
conn=connPool.getConnection();//从连接池获取Connection
Statement stm=null;
stm=conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
rst=stm.executeQuery(sqltext);
}catch(Exception e)
{
e.printStackTrace();
}
connPool.returnConnection(conn);
return rst;
}

[magong]

看看LookForResultSet在第326行(透过getChannelName)被调用的时候，是不是误释放了当前数据库链接。
另外，
①抓ResultSet在手上不是个好习惯，最好从ResultSet中将需要的信息取出来后随即关闭之。
②多表查询，可以构建一个复杂一点的SQL语句，在一次数据库访问过程中搞定