Java中怎么加速读取复制超大文件
今天就跟大家聊聊有关Java中怎么加速读取复制超大文件,可能很多人都不太了解,为了让大家更加了解,小编给大家总结了以下内容,希望大家根据这篇文章可以有所收获。
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(); } } } } }
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