错误处理URLConnection

问题描述：

我有这种方法，从雅虎财务下载.csv文件并将它们保存在本地。它在一个循环中被访问，所以它从列表中下载了许多文件。但是有时候符号输入不正确，不再存在，或连接超时。如何修改此方法，以便连接超时被重试，并且不正确的符号（意味着URL不起作用）只是跳过而不结束程序？错误处理URLConnection

public static void get_file(String symbol){ 

    OutputStream outStream = null; 
    URLConnection uCon = null; 
    InputStream is = null; 

    String finance_url = "http://ichart.finance.yahoo.com/table.csv?s="+symbol; 
    String destination = "C:/"+symbol+"_table.csv"; 

    try { 
     URL Url; 
     byte[] buf; 
     int ByteRead,ByteWritten=0; 
     Url= new URL(finance_url); 

     outStream = new BufferedOutputStream(new FileOutputStream(destination)); 

     uCon = Url.openConnection(); 
     is = uCon.getInputStream();   
     buf = new byte[size]; 

     while ((ByteRead = is.read(buf)) != -1) { 
      outStream.write(buf, 0, ByteRead); 
      ByteWritten += ByteRead; 
     } 

    }catch (Exception e) { 
     System.out.println("Error while downloading "+symbol); 
     e.printStackTrace(); 
    }finally { 
     try { 
      is.close(); 
      outStream.close(); 
     }catch (IOException e) { 
      e.printStackTrace(); 
     } 
    } 
}

你的exeption将被try/catch块捕获。问题是什么？如果出现这样的问题，你的程序是做什么的，你希望它做什么？ – 2012-01-16 15:58:50

答

为什么在抛出异常时再次调用该方法。您可以缩小异常类型以指示何时应该启动重试。

public static void get_file(String symbol){ 

    OutputStream outStream = null; 
    URLConnection uCon = null; 
    InputStream is = null; 

    String finance_url = "http://ichart.finance.yahoo.com/table.csv?s="+symbol; 
    String destination = "C:/"+symbol+"_table.csv"; 

    try { 
     URL Url; 
     byte[] buf; 
     int ByteRead,ByteWritten=0; 
     Url= new URL(finance_url); 

     outStream = new BufferedOutputStream(new FileOutputStream(destination)); 

     uCon = Url.openConnection(); 
     is = uCon.getInputStream();   
     buf = new byte[size]; 

     while ((ByteRead = is.read(buf)) != -1) { 
      outStream.write(buf, 0, ByteRead); 
      ByteWritten += ByteRead; 
     } 

    }catch (Exception e) { 
     getFile(symbol); 
    }finally { 
     try { 
      is.close(); 
      outStream.close(); 
     }catch (IOException e) { 
      e.printStackTrace(); 
     } 
    } 
}

错误处理URLConnection

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