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Why would you ever implement finalize()?

我看到了一些java文档,其代码如下:

public void finalize() {
    if (conn != null) {
        try {
            conn.close();
        } catch (SQLException e) {
        }
    }
}

Is closing a Connection in the finalize method best practice?
Is it enough to close the Connection or does one need to also close other objects such as PreparedStatement?

Answer 1

从贾瓦7起,关闭资源的最佳做法是利用资源:

rel=“noretinger”http://docs.oracle.com/javase/tutorial/essential/vilions/tryResourceClose.html

Answer 2

No, that is not "best practice", or even "passable practice". You have no guarantee when if at all finalizers are called, so it won t work.

相反,你们应该把资源用于一个整体,例如:

try {
  acquire resource
}
finally {
  if (resource was acquired)
    release it
}

Answer 3

如果不是这样,最终确定者不太可能被及时传唤。明确和肯定地清理你们的资源。

/* Acquire resource. */
try {
  /* Use resource. */
}
finally {
  /* Release resource. */
}

Answer 4

一旦获得联系标语,就利用这个标语执行准备的声明/声明/声明,这些标语被放在一个试卷栏中,然后将房屋清理工作,如关闭雕像,并排在座。

指称:

 try{

    Connection conn = DriverManager.getConnection(url,username,password);

    PreparedStatement pStat = conn.prepareStatement("Drop table info");

    pStat.executeUpdate();
      }
       catch(Exception ex){
        }

   finally(){

     pStat.close();
     conn.close();
 }

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