一文探索Java文件读写更高效方式

public void zipFileWithoutBuffer(String outFile){
    long beginTime = System.currentTimeMillis();
    File zipFile = new File(outFile);
    File inputFile = new File(INPUT_FILE);
    try(ZipOutputStream zipOutputStream = new ZipOutputStream(new FileOutputStream(zipFile))) {
        try (InputStream inputStream = new FileInputStream(inputFile)){
            zipOutputStream.putNextEntry(new ZipEntry(inputFile.getName()));
            int temp;
            while ((temp = inputStream.read()) != -1){
                zipOutputStream.write(temp);
            }
        }
        printResult(beginTime,"withoutBuffer");
    } catch (Exception e) {
        e.printStackTrace();
        System.out.println("error"   e.getMessage());
    } 
}

public void zipFileWithBuffer(String outFile){
    long beginTime = System.currentTimeMillis();
    File zipFile = new File(outFile);
    File inputFile = new File(INPUT_FILE);
    try(ZipOutputStream zipOutputStream = new ZipOutputStream(new FileOutputStream(zipFile));
        BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(zipOutputStream)) {
        try (BufferedInputStream bufferedInputStream = new BufferedInputStream(new FileInputStream(inputFile))){
            zipOutputStream.putNextEntry(new ZipEntry(inputFile.getName()));
            int temp;
            while ((temp = bufferedInputStream.read()) != -1){
                bufferedOutputStream.write(temp);
            }
        }
        printResult(beginTime,"withBuffer");
    } catch (Exception e) {
        e.printStackTrace();
        System.out.println("error"   e.getMessage());
    } 
}

public void zipFileWithChannel(String outFile){
    long beginTime = System.currentTimeMillis();
    File zipFile = new File(outFile);
    File inputFile = new File(INPUT_FILE);
    try(ZipOutputStream zipOutputStream = new ZipOutputStream(new FileOutputStream(zipFile));
        WritableByteChannel writableByteChannel = Channels.newChannel(zipOutputStream)) {
        try (FileChannel fileChannel = new FileInputStream(inputFile).getChannel()){
            zipOutputStream.putNextEntry(new ZipEntry(inputFile.getName()));
            fileChannel.transferTo(0,inputFile.length(),writableByteChannel);
        }
        printResult(beginTime,"withChannel");
    } catch (Exception e) {
        e.printStackTrace();
        System.out.println("error"   e.getMessage());
    } 
}

public void zipFileWithMmp(String outFile){
    long beginTime = System.currentTimeMillis();
    File zipFile = new File(outFile);
    File inputFile = new File(INPUT_FILE);
    try(ZipOutputStream zipOutputStream = new ZipOutputStream(new FileOutputStream(zipFile));
        WritableByteChannel writableByteChannel = Channels.newChannel(zipOutputStream)) {
        zipOutputStream.putNextEntry(new ZipEntry(inputFile.getName()));
        MappedByteBuffer mappedByteBuffer = new RandomAccessFile(INPUT_FILE,"r").getChannel()
                .map(FileChannel.MapMode.READ_ONLY,0,inputFile.length());
        writableByteChannel.write(mappedByteBuffer);
        printResult(beginTime,"withMmp");
    } catch (Exception e) {
        e.printStackTrace();
        System.out.println("error"   e.getMessage());
    } 
}

/**
 * Reads a byte of data from this input stream. This method blocks
 * if no input is yet available.
 *
 * @return     the next byte of data, or <code>-1</code> if the end of the
 *             file is reached.
 * @exception  IOException  if an I/O error occurs.
 */public int read() throws IOException {
    return read0();}private native int read0() throws IOException;

/**
 * See
 * the general contract of the <code>read</code>
 * method of <code>InputStream</code>.
 *
 * @return     the next byte of data, or <code>-1</code> if the end of the
 *             stream is reached.
 * @exception  IOException  if this input stream has been closed by
 *                          invoking its {@link #close()} method,
 *                          or an I/O error occurs.
 * @see        java.io.FilterInputStream#in
 */public synchronized int read() throws IOException {
    if (pos >= count) {
        fill();
        if (pos >= count)
            return -1;
    }
    return getBufIfOpen()[pos  ] & 0xff;}