在Java中，在引发异常的方法中关闭变量的正确方法是什么？

Question

In Java, I often close variables in a finally block, like so:

public void someMethod(){
  InputStream inStream = null;
  PreparedStatement pStatement = null;

  try{ do something here }
  catch(Exception ex){ do something here }
  finally{
    try{ if (inStream != null) inStream.close(); } catch(Exception ex){/* do nothing */}
    try{ if (pStatement != null) pStatement.close(); } catch(Exception ex){/* do nothing */}
  }
}

I am wondering, if the method says it throws an exception, is there a place like a "finally" that I can close the method's variables? For example:

public void anotherMethod() throws SQLException {
  // This method doesn't need a try/catch because the method throws an exception.
  InputStream inStream = null;
  PreparedStatement pStatement = null;

  // Where can I ensure these variables are closed?
  // I would prefer not to have them be global variables.
}

Answer 1

The right way would actually be to use the try-with-resources construct that was introduced in Java 7.

public void anotherMethod() throws SQLException {
    try (PreparedStatement st = connection.prepareStatement(...)) {
        // do things with st
    }
}

This ensures that whatever happens in the try block (executed successfully or ends with an exception), the resources will be closed. You don't need to add a catch part since the method throws the SQLException , and more importantly, you don't need to add a finally clause: all opened resources are guaranteed to be closed after that statement.