【记录】代码练习-测试字节流读写四种方式的速度 - 黑马程序员技术交流社区

package com.kxg.Buffer;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
public class TestDemo {
public static void main(String[] args) throws IOException {
long start1 = System.currentTimeMillis();
method1("a.txt", "1.txt");
long end1 = System.currentTimeMillis();
long time1 = (end1 - start1);
long start2 = System.currentTimeMillis();
method2("a.txt", "2.txt");
long end2 = System.currentTimeMillis();
long time2 = (end2 - start2);
long start3 = System.currentTimeMillis();
method3("a.txt", "3.txt");
long end3 = System.currentTimeMillis();
long time3 = (end3 - start3);
long start4 = System.currentTimeMillis();
method4("a.txt", "4.txt");
long end4 = System.currentTimeMillis();
long time4 = (end4 - start4);
System.out.println("普通流一次一个字节：" + time1);
System.out.println("普通流一次一个字节数组：" + time2);
System.out.println("高效流一次一个字节：" + time3);
System.out.println("高效流一次一个字节数组：" + time4);
// 普通流一次一个字节：28725
// 普通流一次一个字节数组：63
// 高效流一次一个字节：59
// 高效流一次一个字节数组：16
}
private static void method4(String srcString, String destString)
throws IOException {
// 高效字节流一次读写一个字节
BufferedInputStream bis = new BufferedInputStream(new FileInputStream(
srcString));
BufferedOutputStream bos = new BufferedOutputStream(
new FileOutputStream(destString));
byte[] by = new byte[1024];
int len = 0;
while ((len = bis.read(by)) != -1) {
bos.write(by, 0, len);
}
}
private static void method3(String srcString, String destString)
throws IOException {
// 高效字节流一次读写一个字节
BufferedInputStream bis = new BufferedInputStream(new FileInputStream(
srcString));
BufferedOutputStream bos = new BufferedOutputStream(
new FileOutputStream(destString));
int len = 0;
while ((len = bis.read()) != -1) {
bos.write(len);
}
}
private static void method2(String srcString, String destString)
throws IOException {
// 一次读写一个字节数组
FileInputStream fis = new FileInputStream(srcString);
FileOutputStream fos = new FileOutputStream(destString);
byte[] by = new byte[1024];
int len = 0;
while ((len = fis.read(by)) != -1) {
fos.write(by, 0, len);
}
fis.close();
fos.close();
}
private static void method1(String srcString, String destString)
throws IOException {
// 一次读写一个字节
FileInputStream fis = new FileInputStream(srcString);
FileOutputStream fos = new FileOutputStream(destString);
int len = 0;
while ((len = fis.read()) != -1) {
fos.write(len);
}
fis.close();
fos.close();
}
}

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