相关疑难解决方法(0)

据说在使用后关闭所有JDBC资源是一个好习惯.但是,如果我有以下代码,是否有必要关闭Resultset和Statement？

Connection conn = null;
PreparedStatement stmt = null;
ResultSet rs = null;
try {
    conn = // Retrieve connection
    stmt = conn.prepareStatement(// Some SQL);
    rs = stmt.executeQuery();
} catch(Exception e) {
    // Error Handling
} finally {
    try { if (rs != null) rs.close(); } catch (Exception e) {};
    try { if (stmt != null) stmt.close(); } catch (Exception e) {};
    try { if (conn != null) conn.close(); } catch (Exception e) {};
}

问题是连接的关闭是否完成了工作,或者是否使用了一些资源.

考虑一下代码:

PreparedStatement ps = null;
ResultSet rs = null;
try {
  ps = conn.createStatement(myQueryString);
  rs = ps.executeQuery();
  // process the results...
} catch (java.sql.SQLException e) {
  log.error("an error!", e);
  throw new MyAppException("I'm sorry. Your query did not work.");
} finally {
  ps.close();
  rs.close();
}

上面没有编译,因为都PreparedStatement.close()和ResultSet.close()抛出java.sql.SQLException.那么我要在finally子句中添加一个try/catch块吗？或者将close语句移动到try子句中？或者只是不打扰打电话？