总结文件复制4种基础方法 - - - 黑马程序员技术交流社区

package it.cast1;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
public class CopyFileDemo1 {
public static void main(String[] args) throws IOException {
// 创建文件输入流和文件输出流
FileInputStream stream = new FileInputStream("F:\\JAVA521\\Day018\\src\\it\\cast1\\陈百强-一生何求.mp3");
FileOutputStream stream2 = new FileOutputStream("E:\\陈百强-一生何求.mp3");
long start = System.currentTimeMillis();
methed(stream, stream2);//耗时62秒
methed1(stream, stream2);//0秒
methed2(stream, stream2);//0秒
methed3(stream, stream2);//0秒
long end = System.currentTimeMillis();
System.out.println("总耗时"+(end-start)/1000+"秒");
}
//高效字节流数字符数组读取
private static void methed3(FileInputStream stream, FileOutputStream stream2) throws IOException {
//高效字节流对象创建
BufferedInputStream bis=new BufferedInputStream(stream);
BufferedOutputStream bos= new BufferedOutputStream(stream2);
//新建数组放读取字节
byte [] arr = new byte [1024];
//读取文件放入字节数组
int read = 0;
while ((read=bis.read(arr))!=-1) {
//把字节数组写入复制的文件中
bos.write(arr, 0, read);
}
//关闭高效字节流
bis.close();
bos.close();
}
//字节数组读取复制文件
private static void methed2(FileInputStream stream, FileOutputStream stream2) throws IOException {
// 新建数组
int read = 0;
byte [] arr = new byte [1024];
//读取文件并把文件中每个字符存入数字
while ((read=stream.read(arr))!=-1) {
//把字节数组写入复制的文件中
stream2.write(arr, 0, read);
}
//关闭数据流
stream.close();
stream2.close();
}
//高效字節流复制文件
private static void methed1(FileInputStream stream, FileOutputStream stream2) throws IOException {
//创建高效字节输出流和输入流
BufferedInputStream bis=new BufferedInputStream(stream);
BufferedOutputStream bos= new BufferedOutputStream(stream2);
//读取
int read = 0;
while ((read = bis.read())!=-1) {
//写入复制
bos.write(read);
}
//关闭字节流
bis.close();
bos.close();
}
//字节流读取复制
public static void methed(FileInputStream stream, FileOutputStream stream2)
throws IOException {
// 读取文件
int read = 0;
while ((read = stream.read()) != -1) {
// 写去文件
stream2.write(read);
}
// 关闭数据流
stream.close();
stream2.close();
}
}

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