java文件复制
java拷贝文件线程package com.zhao_yi.sysutils.classes.copyfile;import java.io.*;import com.zhao_yi.sysutils.SysUtil;import com.zhao_yi.sysutils.classes.StringList;public class CopyFileThread extends Thread {private long CurCopied = 0;private boolean suspendRequested = false;private boolean terminateRequested = false;private StringList SrcFiles = new StringList();private StringList DstFiles = new StringList();private CopyFile copyfile = null;private String ErrMsg = "";public CopyFileThread(CopyFile copyfile) { this.copyfile = copyfile;}public void AddCopyFiles(StringList SrcFiles, StringList DstFiles) { this.SrcFiles.AddStrings(SrcFiles); this.DstFiles.AddStrings(DstFiles);}private boolean CopyOneFile(String SrcFile, String DstFile) { InputStream in = null; OutputStream out = null; try { in = new FileInputStream(SrcFile); out = new FileOutputStream(DstFile); byte[] buf = new byte; int len = 0; while (!interrupted() && !terminateRequested) { len = in.read(buf); if (len == 0) break; out.write(buf, 0, len); copyfile.OnCopyProcess(len); } } catch (IOException ex) { ErrMsg = "拷贝文件的过程中 出现异常: " + ex.getMessage(); } finally { try { in.close(); out.close(); } catch (IOException ex) { ErrMsg = "拷贝文件的过程中 出现异常: " + ex.getMessage(); } return SysUtil.SameText("", ErrMsg); }}public void run() { try { copyfile.OnCopyBegin(); int fileCount = SrcFiles.getCount(); for (int i = 0; i < fileCount; i++) { CheckSuspended(); if (!interrupted() && !terminateRequested) { String SrcFile = SrcFiles.Get(i); String DstFile = DstFiles.Get(i); if (! (SysUtil.ForceDirectories(SysUtil.ExtractFilePath(DstFile)) && CopyOneFile(SrcFile, DstFile)) ) break; } } } catch (Exception ex) { ErrMsg = ex.getMessage(); } finally { copyfile.OnCopyEnd(ErrMsg); }}public synchronized void RequestSuspend() { suspendRequested = false;}public synchronized void RequestResume() { suspendRequested = false; notify();}public synchronized void RequestTerminate() { terminateRequested = true; if (suspendRequested) RequestResume();}public synchronized void CheckSuspended() { while (suspendRequested && !interrupted()) { try { wait(); } catch (InterruptedException ex) { ErrMsg = "暂停的过程中 被强行停止: " + ex.getMessage(); } }}}
Java复制文件速度最快的算法
第一种方法，是采用普通的IO，Buffered流，速度一般；另一种是采用Channel流的transfer方法，速度超快。建议采用第二种方法。
public static long copyFile(File srcFile,File destDir,String newFileName){long copySizes = 0;if(!srcFile.exists()){ System.out.println("源文件不存在"); copySizes = -1;}else if(!destDir.exists()){ System.out.println("目标目录不存在"); copySizes = -1;}else if(newFileName == null){ System.out.println("文件名为null"); copySizes = -1;}else{ try { BufferedInputStream bin = new BufferedInputStream( new FileInputStream(srcFile)); BufferedOutputStream bout = new BufferedOutputStream( new FileOutputStream(new File(destDir,newFileName))); int b = 0 ,i = 0; long t1 = System.currentTimeMillis(); while((b = bin.read()) != -1){ bout.write(b); i++; } long t2 = System.currentTimeMillis(); bout.flush(); bin.close(); bout.close(); copySizes = i; long t = t2-t1; System.out.println("复制了" + i + "个字节\n" + "时间" + t); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); }}return copySizes; }public static long copyFile2(File srcFile,File destDir,String newFileName){long copySizes = 0;if(!srcFile.exists()){ System.out.println("源文件不存在"); copySizes = -1;}else if(!destDir.exists()){ System.out.println("目标目录不存在"); copySizes = -1;}else if(newFileName == null){ System.out.println("文件名为null"); copySizes = -1;}else{ try { FileChannel fcin = new FileInputStream(srcFile).getChannel(); FileChannel fcout = new FileOutputStream( new File(destDir,newFileName)).getChannel(); ByteBuffer buff = ByteBuffer.allocate(1024); int b = 0 ,i = 0;// long t1 = System.currentTimeMillis(); long size = fcin.size(); fcin.transferTo(0,fcin.size(),fcout); //fcout.transferFrom(fcin,0,fcin.size()); //一定要分清哪个文件有数据，那个文件没有数据，数据只能从有数据的流向 //没有数据的文件// long t2 = System.currentTimeMillis(); fcin.close(); fcout.close(); copySizes = size;// long t = t2-t1;// System.out.println("复制了" + i + "个字节\n" + "时间" + t);// System.out.println("复制了" + size + "个字节\n" + "时间" + t); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); }}return copySizes; }
使用nio和io来测试一个100m的文件
import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.nio.ByteBuffer;import java.nio.channels.FileChannel;public class CopyFile { /** * nio拷贝 * @param inFile源文件 * @param outFile 目标文件 * @return * @throws Exception */ public static long FileChannelCopy(String inFile,String outFile) throws Exception { long begin = System.currentTimeMillis(); File in = new File(inFile); File out = new File(outFile); FileInputStream fin = new FileInputStream(in); FileOutputStream fout = new FileOutputStream(out); FileChannel inc = fin.getChannel(); FileChannel outc = fout.getChannel(); int bufferLen = 2097152; ByteBuffer bb = ByteBuffer.allocateDirect(bufferLen); while (true) { int ret = inc.read(bb); if (ret == -1) { fin.close(); fout.flush(); fout.close(); break; } bb.flip(); outc.write(bb); bb.clear(); } long end = System.currentTimeMillis(); long runtime = 0; if(end >begin) runtime = end - begin; return runtime; } /** * io拷贝 * @param inFile 源文件 * @param outFile 目标文件 * @return * @throws Exception */ public static long FileStraeamCopy(String inFile,String outFile) throws Exception { long begin = System.currentTimeMillis(); File in = new File(inFile); File out = new File(outFile); FileInputStream fin=new FileInputStream(in); FileOutputStream fout=new FileOutputStream(out); int length=2097152;//2m内存 byte[] buffer=new byte; while(true) { int ins=fin.read(buffer); if(ins==-1) { fin.close(); fout.flush(); fout.close(); break; }else fout.write(buffer,0,ins); } long end = System.currentTimeMillis(); long runtime = 0; if(end > begin) runtime = end - begin; return runtime; } static public void main(String args[]) throws Exception { String inFile = "D:\\big4.pdf"; //源文件 String outFile = "D:\\big4copy1.pdf"; //输出文件1 String outFile2 = "D:\\big4copy2.pdf"; //输出文件2 long runtime1,runtime2; runtime1 = FileChannelCopy(inFile,outFile); runtime2 = FileStraeamCopy(inFile,outFile2); System.out.println("FileChannelCopy running time:" + runtime1); System.out.println("FileStraeamCopy running time:" + runtime2); }}
一个简单的方式就是调用cmd命令,使用windows自带的功能来替你完成这个功能
我给你写个例子
import java.io.*;public class test{ public static void main(String[] args){ BufferedReader in = null; try{ // 这里你就当作操作对dos一样好了 不过cmd /c 一定不要动 Process pro =Runtime.getRuntime().exec("cmd /c copy d:\\ReadMe.txt e:\\"); in = new BufferedReader(new InputStreamReader(pro.getInputStream())); String str; while((str = in.readLine()) != null){ System.out.println(str); } }catch(Exception e){ e.printStackTrace(); }finally{ if(in != null){ try{ in.close(); }catch(IOException i){ i.printStackTrace(); } } } }}
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