关于WEB项目中访问连接池的问题
最近学习做了一个简单的WEB项目，遇到一个难题，在管理页面中创建了一个连接池，从数据库里看连接也是成功的，但是在其它类中获取连接总是提示异常，哪位高手给帮忙看一下
这是连接池

public final class ConnectionPoolInit {
  private static BasicDataSource basicDataSource = null;

  private ConnectionPoolInit(){}

  public static void createDataSource() throws Exception{
  Properties properties = new Properties();
  InputStream inputStream = ConnectionPoolInit.class.
  getClassLoader().getResourceAsStream("dbcpconfig.properties");
  properties.load(inputStream);
  basicDataSource = (BasicDataSource) BasicDataSourceFactory.createDataSource(properties);
  }

  public static Connection getConnection() throws Exception{
  return basicDataSource.getConnection();
  }

这是获得连接

  public UserBean loginControl(String uid,String pwd) throws Exception{
  UserBean userBean = new UserBean();
  connection = ConnectionPoolInit.getConnection();

这是返回异常

严重: Servlet.service() for servlet [LoginServlet] in context with path [/chart] threw exception [org.apache.tomcat.dbcp.dbcp.PoolingDataSource$PoolGuardConnectionWrapper cannot be cast to org.apache.tomcat.dbcp.dbcp.BasicDataSource] with root cause
javax.servlet.ServletException: org.apache.tomcat.dbcp.dbcp.PoolingDataSource$PoolGuardConnectionWrapper cannot be cast to org.apache.tomcat.dbcp.dbcp.BasicDataSource


------解决方案--------------------
public final class ConnectionPoolInit {
private static BasicDataSource basicDataSource = null;
static{
if(basicDataSource == null)
{
Properties properties = new Properties();
InputStream inputStream = ConnectionPoolInit.class.
getClassLoader().getResourceAsStream("dbcpconfig.properties");
properties.load(inputStream);
basicDataSource = (BasicDataSource) BasicDataSourceFactory.createDataSource(properties);
}
}

public static synchronized Connection getConnection() throws Exception{
return basicDataSource.getConnection();
}
}
帮你改造了下，调用：ConnectionPoolInit.getConnection();注意红色的同步关键字必须加上。

------解决方案--------------------
和一楼的差不多，也帮楼主该了一下代码：

public final class ConnectionPoolInit {
private static BasicDataSource basicDataSource = null;
static{
Properties properties = new Properties();
InputStream inputStream = ConnectionPoolInit.class.
getClassLoader().getResourceAsStream("dbcpconfig.properties");
properties.load(inputStream);
basicDataSource = (BasicDataSource) BasicDataSourceFactory.createDataSource(properties);
}
  
  
private ConnectionPoolInit(){}

public static void createDataSource() throws Exception{
return basicDataSource
}

public static Connection getConnection() throws Exception{
return basicDataSource.getConnection();
}
｝

用楼主的方法时过前台管理页面访问servlet来初始化连接的是可以的，是因为创建的数据库连接池，如果启动服务后，从来没有访问那个servlet页面，访问其他的方法中只包含：ConnectionPoolInit.getConnection();是肯定会报错的，因为还没有初始化连接池。

分析的不一定对，楼主可以试试