Java 如何正确关闭从FileOutputStream获取的FileChannel

我刚刚在当前的Eclipe Juno候选版本中打开了一些旧代码，并注意到一个闪亮的新警告：资源泄漏。它是由如下代码触发的：

FileChannel out = new FileOutputStream(file).getChannel();
try
{
    ...Do something with out...
}
finally
{
    out.close();
}

FileOutputStream outStream = new FileOutputStream(file);
try
{
    FileChannel out = outStream.getChannel();
    try
    {
        ...Do something with out...
    }
    finally
    {
        out.close();
    }
}
finally
{
    outStream.close();
}

Eclipse认为创建的文件输出流是一个资源泄漏。实际上，我不确定这是否是一个错误的警告（FileChannel的close方法也不关闭流），或者这是否真的是一个资源泄漏。我将代码更改为：

FileOutputStream outStream = new FileOutputStream(file);
try
{
    FileChannel out = outStream.getChannel();
    ...Do something with out...
}
finally
{
    outStream.close();
}

警告现在消失了，但我不确定是否必须调用FileChannel的close方法。所以也许它看起来应该是这样的：

FileChannel out = new FileOutputStream(file).getChannel();
try
{
    ...Do something with out...
}
finally
{
    out.close();
}

FileOutputStream outStream = new FileOutputStream(file);
try
{
    FileChannel out = outStream.getChannel();
    try
    {
        ...Do something with out...
    }
    finally
    {
        out.close();
    }
}
finally
{
    outStream.close();
}

如果使用一个文件输入通道和一个文件输出通道，那么这将导致四个嵌套的try…finally块，所有这些都会变得有点臃肿

---

你觉得怎么样？是否真的有必要关闭通道和溪流？还是关闭流就足够了？

啊，在FileOutputStream的close（）方法的文档中找到了答案：

If this stream has an associated channel then the channel is closed as well.

因此，关闭流就足够了