java写文件方法之比较

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