Java加速读取复制超大文件

用文件通道（FileChannel）来实现文件复制，供大家参考，具体内容如下

不考虑多线程优化，单线程文件复制最快的方法是(文件越大该方法越有优势，一般比常用方法快30+%):

直接上代码：

package test;
 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.nio.channels.FileChannel;

 public class Test {
public static void main(String[] args) {
File source = new File("E:\\tools\\fmw_12.1.3.0.0_wls.jar");
File target = new File("E:\\tools\\fmw_12.1.3.0.0_wls-copy.jar");
long start, end;

start = System.currentTimeMillis();
fileChannelCopy(source, target);
end = System.currentTimeMillis();
System.out.println("文件通道用时：" + (end - start) + "毫秒");

start = System.currentTimeMillis();
copy(source, target);
end = System.currentTimeMillis();
System.out.println("普通缓冲用时：" + (end - start) + "毫秒");
}

/**
  * 使用文件通道的方式复制文件
  * @param source 源文件
  * @param target 目标文件
  */
 public static void fileChannelCopy(File source, File target) {


   FileInputStream in = null;
   FileOutputStream out = null;
   FileChannel inChannel = null;
   FileChannel outChannel = null;
   try {
    in = new FileInputStream(source);
    out = new FileOutputStream(target);
    inChannel = in.getChannel();//得到对应的文件通道
   outChannel = out.getChannel();//得到对应的文件通道
   inChannel.transferTo(0, inChannel.size(), outChannel);//连接两个通道，并且从inChannel通道读取，然后写入outChannel通道
  } catch (IOException e) {
    e.printStackTrace();
   } finally {
    try {
     in.close();
     inChannel.close();
     out.close();
     outChannel.close();
    } catch (IOException e) {
     e.printStackTrace();
    }


   }


  }
 
/**
* 普通缓冲复制
* @param source 源文件
* @param target 目标文件
*/
public static void copy (File source, File target) {
InputStream in = null;
BufferedOutputStream out = null;
try {
in = new BufferedInputStream(new FileInputStream(source));
out = new BufferedOutputStream(new FileOutputStream(target));
byte[] buf = new byte[4096];
int i;
while ((i = in.read(buf)) != -1) {
out.write(buf, 0, i);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if (null != in) {
in.close();
}
if (null != out) {
out.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
 }

 }

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。