java的四种文件写入方法比较

原创地址不详

从老紫竹的网站上转来滴

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;

/**
* 测试各种写文件的方法性能。
*
* @author 老紫竹 JAVA世纪网(java2000.net)
*
*/
public class T {

public static void main(String[] args) {
    FileOutputStream out = null;
    FileOutputStream outSTr = null;
    BufferedOutputStream Buff = null;
    FileWriter fw = null;
    int count = 1000000;// 写文件行数
    try {
      byte[] bs = "测试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执行耗时:" + (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执行耗时:" + (end0 - begin0) + " 豪秒");

      fw = new FileWriter("C:/add2.txt");
      long begin3 = System.currentTimeMillis();
      for (int i = 0; i < count; i++) {
        fw.write("测试java 文件操作\r\n");
      }
      fw.flush();
      fw.close();
      long end3 = System.currentTimeMillis();
      System.out.println("FileWriter执行耗时:" + (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执行耗时:" + (end4 - begin4) + " 豪秒");
    } catch (Exception e) {
      e.printStackTrace();
    } finally {
      try {
        fw.close();
        Buff.close();
        outSTr.close();
        out.close();
      } catch (Exception e) {
        e.printStackTrace();
      }
    }
}
}

在我的笔记本上，运行结果如下

FileOutputStream执行耗时:4891 豪秒

BufferedOutputStream执行耗时:78 豪秒

FileWriter执行耗时:438 豪秒

FileChannel执行耗时:2812 豪秒

当然最终生成的文件都是正确的

总结：

BufferedOutputStream 由于有缓冲，性能明显好

FileOutputStream 性能最差，因为其每次都写入字节。

FileWriter 性能很一般

FileChannel使用了nio,但如果没有缓冲，必能太指望性能了