今天review代码也看到了“大神”用老方法来实现文件拷贝。今天归结一下使用Java语言怎样实现高速文件复制:
代码1——使用文件通道的方式:
import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.nio.channels.FileChannel; public class Test { public static void main(String[] args){ long start = System.currentTimeMillis(); FileInputStream fileInputStream = null; FileOutputStream fileOutputStream = null; FileChannel inFileChannel = null; FileChannel outFileChannel = null; try { fileInputStream = new FileInputStream(new File("C:\from\不是闹着玩的.flv")); fileOutputStream = new FileOutputStream(new File("C:\to\不是闹着玩的.flv")); inFileChannel = fileInputStream.getChannel(); outFileChannel = fileOutputStream.getChannel(); inFileChannel.transferTo(0, inFileChannel.size(), outFileChannel);//连接两个通道。从in通道读取数据写入out通道。} catch (IOException e) { e.printStackTrace(); } finally { try { if(fileInputStream != null){ fileInputStream.close(); } if(inFileChannel != null){ inFileChannel.close(); } if(fileOutputStream != null){ fileOutputStream.close(); } if(outFileChannel != null){ outFileChannel.close(); } } catch (IOException e) { e.printStackTrace(); } } long end = System.currentTimeMillis(); System.out.println("视频文件从“from”目录拷贝到“to”文件须要" + (end - start) + "毫秒。
"); } }
代码执行结果为:
代码2——使用缓冲输入输出流
import java.io.BufferedInputStream; import java.io.BufferedOutputStream; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; public class Test { public static void main(String[] args){ long start = System.currentTimeMillis(); InputStream fileInputStream = null; OutputStream fileOutputStream = null; try { fileInputStream = new BufferedInputStream( new FileInputStream(new File("C:\from\不是闹着玩的.flv"))); fileOutputStream = new BufferedOutputStream(new FileOutputStream(new File("C:\to\不是闹着玩的.flv"))); byte[] bufferArray = new byte[1024*1024]; int length; while ((length = fileInputStream.read(bufferArray)) != -1) { fileOutputStream.write(bufferArray, 0, length); } } catch (IOException e) { e.printStackTrace(); } finally { try { if(fileInputStream != null){ fileInputStream.close(); } if(fileOutputStream != null){ fileOutputStream.close(); } } catch (IOException e) { e.printStackTrace(); } } long end = System.currentTimeMillis(); System.out.println("视频文件从“from”目录拷贝到“to”文件须要" + (end - start) + "毫秒。"); } }代码执行结果为:
代码3——使用文件输入输出流的方式:
import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; public class Test { public static void main(String[] args){ long start = System.currentTimeMillis(); FileInputStream fileInputStream = null; FileOutputStream fileOutputStream = null; try{ fileInputStream = new FileInputStream(new File("C:\from\不是闹着玩的.flv")); //读入原文件 fileOutputStream = new FileOutputStream("C:\to\不是闹着玩的.flv"); byte[] bufferArray = new byte[1024*1024]; int length; while ((length = fileInputStream.read(bufferArray)) != -1) { fileOutputStream.write(bufferArray, 0, length); } } catch (IOException e) { e.printStackTrace(); } finally { try { if(fileInputStream != null){ fileInputStream.close(); } if(fileOutputStream != null){ fileOutputStream.close(); } } catch (IOException e) { e.printStackTrace(); } } long end = System.currentTimeMillis(); System.out.println("视频文件从“from”目录拷贝到“to”文件须要" + (end - start) + "毫秒。"); } }代码执行结果为:
代码1、代码2和代码3复制的是同样的文件,通过对比不难得出结论::尝试使用文件时,文件拷贝输入和输出流可能是一个更好的办法。
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