java试试finally块关闭流 [英] java try finally block to close stream

问题描述

我想在finally块中关闭我的流，但是它会抛出一个 IOException ，所以好像我必须嵌套另一个 try 块在我的最后块为了关闭流。这是正确的做法吗？看起来有点笨重。

以下是代码：

  public void read（）{
 try {
r = new BufferedReader（new InputStreamReader（address.openStream（）））; 
 String inLine; （（inLine = r.readLine（））！= null）{
 System.out.println（inLine）; 
} 
} catch（IOException readException）{
 readException.printStackTrace（）; 
} finally {
 try {
 if（r！= null）r.close（）; 
} catch（Exception e）{
 e.printStackTrace（）; 
 
 
 
 
 
 $ b $ div class = 
 
 
 
 
 $ b 
这是一个笨蛋。至少java7的尝试资源修复。
 
 
 
在java7之前，你可以使一个 closeStream 函数吞下它： 
 
 
  public void closeStream（Closeable s）{
 try（
 if（s！= null）s。关（）; 
 catch（IOException e）{
 // Log or rethrow as unchecked（like RuntimException）;）
} 
} 
  
或者把try ...终于在try catch里面： 
 
 
  try {
 BufferedReader r = new BufferedReader（new InputStreamReader（address.openStream（）））; 
尝试{
 
 String inLine; （（inLine = r.readLine（））！= null）{
 System.out.println（inLine）; 
} 
} finally {
 r.close（）; 
} 
} catch（IOException e）{
 e.printStackTrace（）; 
 
 
 
 $ b $ p 
 $ b 
它更加冗长，在finally中会有一个例外，它在语义上更接近于引入的试用资源 Java 7。
 
I want to close my stream in the finally block, but it throws an IOException so it seems like I have to nest another try block in my finally block in order to close the stream. Is that the right way to do it? It seems a bit clunky.

Here's the code:
 public void read() {
    try {
        r = new BufferedReader(new InputStreamReader(address.openStream()));
        String inLine;
        while ((inLine = r.readLine()) != null) {
            System.out.println(inLine);
        }
    } catch (IOException readException) {
        readException.printStackTrace();
    } finally {
        try {
            if (r!=null) r.close();
        } catch (Exception e){
            e.printStackTrace();
        }
    }


}

解决方案

  
It seems a bit clunky.
It is. At least java7's try with resources fixes that.

Pre java7 you can make a closeStream function that swallows it:
public void closeStream(Closeable s){
    try{
        if(s!=null)s.close();
    }catch(IOException e){
        //Log or rethrow as unchecked (like RuntimException) ;)
    }
}
Or put the try...finally inside the try catch:
try{
    BufferedReader r = new BufferedReader(new InputStreamReader(address.openStream()));
    try{

        String inLine;
        while ((inLine = r.readLine()) != null) {
            System.out.println(inLine);
        }
    }finally{
        r.close();
    }
}catch(IOException e){
    e.printStackTrace();
}
It's more verbose and an exception in the finally will hide one in the try but it's semantically closer to the try-with-resources introduced in Java 7.

                        
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