Java字节流和字符流的复制案例及测速
Java字节流和字符流的复制案例及测速
案例
package com.cnblogs;
import java.io.*;
import java.util.Scanner;
public class TestCopyFile {
public static void main(String[] args) {
System.out.println("请输入您要复制的源文件路径：");
String f = new Scanner(System.in).nextLine();
System.out.println("请输入您目标文件的路径：");
String t = new Scanner(System.in).nextLine();
InputStream in1 = null;
OutputStream out1 = null;
try {
in1 =new BufferedInputStream(new FileInputStream(f)) ;
out1 =new BufferedOutputStream(new FileOutputStream(t)) ;
int result;
while((result = in1.read()) != -1){
out1.write(result);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
out1.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
in1.close();
} catch (IOException e) {
e.printStackTrace();
}
}
/*
字符流复制的图片没法打开,字节流可以。
*/
//
//// Reader in = null;
//// Writer out = null;
////
//// try {
//// in = new BufferedReader(new FileReader(f));
//// out = new BufferedWriter(new FileWriter(t));
//// int result = 0;
//// while ((result = in.read()) != -1){
//// out.write(result);
//// }
//// System.out.println("文件复制成功！");
//// } catch (Exception e) {
//// System.out.println("文件复制失败！");
//// e.printStackTrace();
//// /*
//// 一定会执行的代码需要放在finally{}中，比如关流
//// 关流操作是有顺序的，如果有多个流，先创建的后关闭
//// 多条关流语句需要各自try-catch
//// */
//// } finally {
//// try {
//// out.close();
//// } catch (IOException e) {
//// e.printStackTrace();
//// }
//// try {
//// in.close();
//// } catch (IOException e) {
//// e.printStackTrace();
//// }
//// }
}
}
总结：
字符流只能复制文本文件，复制的图片，视频尽管可以复制，但会造成文件损坏，
而字节流可以实现完美的复制，不会损坏文件，字节流更接近底层。
测速
package com.cnblogs.api;
import java.io.*;
/*
测试速度，用136M的视频文件来做复制粘贴实验
*/
public class TestSpeed {
public static void main(String[] args) {
// method1();//花费时间：429937
// method2();//花费时间：4308
// method3();//花费时间：12858
// method4();//花费时间：8245
method5();//花费时间：3289
}
private static void method5() {
//测试BufferedInputStream和BufferedOutputStream的速度 加上“车”
long start = System.currentTimeMillis();
InputStream in1 = null;
OutputStream out1 = null;
try {
in1 =new BufferedInputStream(new FileInputStream("E:\\1.wmv")) ;
out1 =new BufferedOutputStream(new FileOutputStream("E:\\study\\1.wmv")) ;
int result;
byte[] car = new byte[1024*1024*1024];
while((result = in1.read(car)) != -1){
out1.write(car,0,result);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
out1.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
in1.close();
} catch (IOException e) {
e.printStackTrace();
}
}
long end = System.currentTimeMillis();
System.out.println("花费时间：" + (end - start));
}
private static void method4() {
//测试BufferedReader和BufferedWriter的速度
long start = System.currentTimeMillis();
Reader in1 = null;
Writer out1 = null;
try {
in1 =new BufferedReader(new FileReader("E:\\1.wmv"));
out1 =new BufferedWriter(new FileWriter("E:\\study\\1.wmv"));
int result;
while((result = in1.read()) != -1){
out1.write(result);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
out1.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
in1.close();
} catch (IOException e) {
e.printStackTrace();
}
}
long end = System.currentTimeMillis();
System.out.println("花费时间：" + (end - start));
}
private static void method3() {
//测试FileReader和FileWriter的速度
long start = System.currentTimeMillis();
Reader in1 = null;
Writer out1 = null;
try {
in1 = new FileReader("E:\\1.wmv") ;
out1 = new FileWriter("E:\\study\\1.wmv") ;
int result;
while((result = in1.read()) != -1){
out1.write(result);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
out1.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
in1.close();
} catch (IOException e) {
e.printStackTrace();
}
}
long end = System.currentTimeMillis();
System.out.println("花费时间：" + (end - start));
}
private static void method2() {
//测试BufferedInputStream和BufferedOutputStream的速度
long start = System.currentTimeMillis();
InputStream in1 = null;
OutputStream out1 = null;
try {
in1 =new BufferedInputStream(new FileInputStream("E:\\1.wmv")) ;
out1 =new BufferedOutputStream(new FileOutputStream("E:\\study\\1.wmv")) ;
int result;
while((result = in1.read()) != -1){
out1.write(result);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
out1.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
in1.close();
} catch (IOException e) {
e.printStackTrace();
}
}
long end = System.currentTimeMillis();
System.out.println("花费时间：" + (end - start));
}
private static void method1() {
//测试FileInputStream和FileOutputStream的速度
long start = System.currentTimeMillis();
InputStream in1 = null;
OutputStream out1 = null;
try {
in1 = new FileInputStream("E:\\1.wmv");
out1 = new FileOutputStream("E:\\study\\1.wmv");
int result;
while((result = in1.read()) != -1){
out1.write(result);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
out1.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
in1.close();
} catch (IOException e) {
e.printStackTrace();
}
}
long end = System.currentTimeMillis();
System.out.println("花费时间：" + (end - start));
}
}
