java寫文件方法之比較

    import java.io.BufferedOutputStream;

    import java.io.File;

    import java.io.FileOutputStream;

    import java.io.FileWriter;

    import java.nio.ByteBuffer;

    import java.nio.channels.FileChannel;


/**  
 * 測試各種寫文件的方法性能。  
 *   
 *   
 */  
public class T {   

  public static void main(String[] args) {   
    FileOutputStream out = null;   
    FileOutputStream outSTr = null;   
    BufferedOutputStream Buff = null;   
    FileWriter fw = null;   
    int count = 1000000;// 寫文件行數   
    try {   
      byte[] bs = "測試java 文件操作/r/n".getBytes();   
      out = new FileOutputStream(new File("C:/add.txt"));   
      long begin = System.currentTimeMillis();   
      for (int i = 0; i < count; i++) {   
        out.write(bs);   
      }   
      out.close();   
      long end = System.currentTimeMillis();   
      System.out.println("FileOutputStream執行耗時:" + (end - begin) + " 豪秒");   

      outSTr = new FileOutputStream(new File("C:/add0.txt"));   
      Buff = new BufferedOutputStream(outSTr);   
      long begin0 = System.currentTimeMillis();   
      for (int i = 0; i < count; i++) {   
        Buff.write(bs);   
      }   
      Buff.flush();   
      Buff.close();   
      long end0 = System.currentTimeMillis();   
      System.out.println("BufferedOutputStream執行耗時:" + (end0 - begin0) + " 豪秒");   

      fw = new FileWriter("C:/add2.txt");   
      long begin3 = System.currentTimeMillis();   
      for (int i = 0; i < count; i++) {   
        fw.write("測試java 文件操作/r/n");   
      }   
      fw.flush();   
      fw.close();   
      long end3 = System.currentTimeMillis();   
      System.out.println("FileWriter執行耗時:" + (end3 - begin3) + " 豪秒");   

      long begin4 = System.currentTimeMillis();   
      String path = "C:/add3.txt";   
      ByteBuffer bb = ByteBuffer.wrap(bs);   
      FileChannel out2 = new FileOutputStream(path).getChannel();   
      for (int i = 0; i < count; i++) {   
        out2.write(bb);   
        bb.rewind();   
      }   

      out2.close();   
      long end4 = System.currentTimeMillis();   
      System.out.println("FileChannel執行耗時:" + (end4 - begin4) + " 豪秒");   
    } catch (Exception e) {   
      e.printStackTrace();   
    } finally {   
      try {   
        fw.close();   
        Buff.close();   
        outSTr.close();   
        out.close();   
      } catch (Exception e) {   
        e.printStackTrace();   
      }   
    }   
  }   
}  </pre>運行結果如下 <p style="text-indent:2em;">FileOutputStream執行耗時:4891 豪秒 </p>

BufferedOutputStream執行耗時:78 豪秒 
FileWriter執行耗時:438 豪秒 
FileChannel執行耗時:2812 豪秒 
當然最終生成的文件都是正確的 
總結： 
BufferedOutputStream 由于有緩沖，性能明顯好 
FileOutputStream 性能最差，因為其每次都寫入字節。 
FileWriter 性能很一般 
FileChannel使用了nio,但如果沒有緩沖，必能太指望性能了