示例代码：如何正确close从连接池中取得的db连接

最新推荐文章于 2025-08-13 09:34:17 发布

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本文提供了一个使用连接池获取数据库连接的正确示例代码。该示例展示了如何创建Statement、执行查询并正确关闭资源，确保连接能够返回到连接池中重复使用。

Here is an example of properly written code to use a db connection obtained from a connection pool:

  Connection conn = null;
  Statement stmt = null;  // Or PreparedStatement if needed
  ResultSet rs = null;
  try {
    conn = ... get connection from connection pool ...
    stmt = conn.createStatement("select ...");
    rs = stmt.executeQuery();
    ... iterate through the result set ...
    rs.close();
    rs = null;
    stmt.close();
    stmt = null;
    conn.close(); // Return to connection pool
    conn = null;  // Make sure we don't close it twice
  } catch (SQLException e) {
    ... deal with errors ...
  } finally {
    // Always make sure result sets and statements are closed,
    // and the connection is returned to the pool
    if (rs != null) {
      try { rs.close(); } catch (SQLException e) { ; }
      rs = null;
    }
    if (stmt != null) {
      try { stmt.close(); } catch (SQLException e) { ; }
      stmt = null;
    }
    if (conn != null) {
      try { conn.close(); } catch (SQLException e) { ; }
      conn = null;
    }
  }

摘自：

The Apache Jakarta Tomcat 5 Servlet/JSP Container
JNDI Datasource HOW-TO