常用的java片段

1. 使用NIO进行文件copy

public static void fileCopy( File in, File out )    
            throws IOException    
    {    
        FileChannel inChannel = new FileInputStream( in ).getChannel();    
        FileChannel outChannel = new FileOutputStream( out ).getChannel();    
        try   
        {    
//          inChannel.transferTo(0, inChannel.size(), outChannel);      // original -- apparently has trouble copying large files on Windows    
  
            // magic number for Windows, 64Mb - 32Kb)    
            int maxCount = (64 * 1024 * 1024) - (32 * 1024);    
            long size = inChannel.size();    
            long position = 0;    
            while ( position < size )    
            {    
               position += inChannel.transferTo( position, maxCount, outChannel );    
            }    
        }    
        finally   
        {    
            if ( inChannel != null )    
            {    
               inChannel.close();    
            }    
            if ( outChannel != null )    
            {    
                outChannel.close();    
            }    
        }    
    }  

2、Http代理设置

System.getProperties().put("http.proxyHost", "someProxyURL");    
System.getProperties().put("http.proxyPort", "someProxyPort");    
System.getProperties().put("http.proxyUser", "someUserName");    
System.getProperties().put("http.proxyPassword", "somePassword");  

3、