谁用过dbpool?

Question

我链接sqlserver2000时报这样的错?
java.lang.NullPointerException at java.lang.String.concat(String.java:1503) at com.office.util.DataOperation.updateData(DataOperation.java:259) at com.system.log.bean.LogBean.insert(LogBean.java:35) at com.office.filters.SystemServlet.service(SystemServlet.java:94) at javax.servlet.http.HttpServlet.service(HttpServlet.java:853) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:247) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193) at com.office.filters.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:76) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:213) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:256) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995) at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2422) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:180) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643) at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:171) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:163) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:174) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995) at org.apache.coyote.tomcat4.CoyoteAdapter.service(CoyoteAdapter.java:199) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:828) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:700) at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:584) at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:683) at java.lang.Thread.run(Thread.java:534)

Answer 1

在com.office.util.DataOperation.updateData中我这样定义:
private ConnectionPoolManager poolManager;
{
        try {
            poolManager = ConnectionPoolManager .getInstance();
        } catch (IOException e) {
            logger.error(e.getMessage());
        }
    }
引用
public int updateData(SQLObject sqlObj) {
        Connection conn = null;
        try {
            conn = poolManager.getConnection("system");
            if (sqlObj == null) {
            logger.error("更新sql语句中为null！");
            throw new SystemException("更新sql语句中为null！");
        }
        PreparedStatement pst = null;
        if (conn == null)throw new SystemException(
                "更新数据时出现了错误:connection is null!");
        int iCount;
         try {
            pst = conn.prepareStatement(sqlObj.getSql());
            Vector params = sqlObj.getParams();
            for (int i = 0; i < params.size(); i++) {
                if (params.get(i) == null) {
                    logger.error("更新sql语句中第" + (i + 1) + "参数为null！");
                    throw new SystemException("更新sql语句中第" + (i + 1) +
                                              "参数为null！");
                }
                pst.setObject(i + 1, params.get(i));
            }
            iCount = pst.executeUpdate();
            conn.commit();
            return iCount;
        } catch (SQLException sql) {
            try {
                conn.rollback();
            } catch (SQLException sqle) {
                logger.error("rollback show error:".concat(sqle.getMessage()));
                throw new SystemException("rollback show error:".concat(sqle.
                        getMessage()));
            }
            logger.error("" + sql.getErrorCode());
            logger.error(sql.getMessage());
            throw new SystemException("更新数据时出现了错误:".concat(sql.getMessage()));
        } finally {
            try {
                pst.close();
            } catch (SQLException sqle) {
                logger.error(sqle.getMessage());
                throw new SystemException("更新数据关闭时出错发生错误:".concat(sqle.
                        getMessage()));
            }
        }
        } catch (Exception e) {
            logger.error("更新数据发生错误:".concat(e.getMessage()));
            throw new SystemException("更新数据发生错误:".concat(e.getMessage()));
        } finally {
            try {
                if (conn != null)
                    conn.close();
            } catch (SQLException e) {
                logger.error("search data error:".concat(e.getMessage()));
            }        }
    }

Answer 2

结果总是这句报错pst = conn.prepareStatement(sqlObj.getSql());

Answer 3

你要查看一下你的Connection为什么取得是Null，需要Debug你的ConnectionPoolManager类，这个里面可能有问题，有可能数据库联接配置错误

Answer 4

Connection不为空,为空的话 会在这里抛出异常:
if (conn == null)throw new SystemException(
                "更新数据时出现了错误:connection is null!");

Answer 5

ConnectionPoolManager类是DBPool自带的类....