上G文件复制的三种方法

需求： 通过tomcat上传到指定目录，成功后复制到指定目录下，大文件复制

方式：

1. 通过文件流方式(文件越大速度越慢)

    public static void copyFile(String oldPath, String newPath) {
        int byteread = 0;

        File oldFile = new File(oldPath);
        if (oldFile.exists()) { //文件存在时
            try (InputStream inStream = new FileInputStream(oldPath);
                 FileOutputStream fs = new FileOutputStream(newPath)) {

                byte[] buffer = new byte[1444];
                while ((byteread = inStream.read(buffer)) != -1) {
                    fs.write(buffer, 0, byteread);
                }
            } catch (IOException e) {
                log.info("copyFile error:" + e.getMessage());
            }
        } else {
            log.info("oldFile is not exists, oldPath:" + oldPath);
        }
    }

2. 通过FileChannel方式(需要设置内存大小，容易报内存溢出等错误)

public static void copyFileNIO(String oldPath, String newPath) {
        try {
            File f1 = new File(oldPath);
            File f2 = new File(newPath);
            //创建输入流
            FileInputStream fis = new FileInputStream(f1);
            //根据读取流创建读取通道，同时将文件中的内容读入到通道中
            FileChannel rChannel = fis.getChannel();
            //创建输出流
            FileOutputStream fos = new FileOutputStream(f2);
            //根据输出流创建写入通道，将通道中的内容写入到文件中
            FileChannel wChannel = fos.getChannel();

            //创建缓冲区
            ByteBuffer bBuffer = ByteBuffer.allocate((int) f1.length());
            //将输入通道中的内容输入到缓冲区中
            rChannel.read(bBuffer);

            //将缓冲区的指针反转，指向起始位置
            bBuffer.flip();
            //将缓冲区的内容写入到输出通道
            wChannel.write(bBuffer);
            log.info(newPath + ",拷贝成功！");

            //关流
            fis.close();
            fos.close();
        } catch (Exception e) {
            log.info("copyFile error:" + e.getMessage());
        }
    }

3. 使用shell命令(需要注意线程阻塞或死锁问题)

// 使用数组的方式可以解决上传的文件名包含特殊字符 空格等
String[] shell = new String[]{"cp", oldPath, newPath};
Process process = Runtime.getRuntime().exec(shell);

// 使用new RunThread方式解决waitFor会阻塞线程或死锁问题
new RunThread(process.getInputStream(), "INFO").start();
new RunThread(process.getErrorStream(), "ERR").start();

int value = process.waitFor();
if (value == 0) {
     log.info("复制成功");
 } else {
     log.info("复制失败");
 }


public class RunThread extends Thread {
    private InputStream is;
    private String printType;

    RunThread(InputStream is, String printType) {
        this.is = is;
        this.printType = printType;
    }

    @Override
    public void run() {
        try {
            InputStreamReader isr = new InputStreamReader(is);
            BufferedReader br = new BufferedReader(isr);
            String line;
            while ((line = br.readLine()) != null) {
                log.info(printType + ">" + line);
            }
        } catch (IOException ioe) {
            log.info("RunThread error:", ioe);
        }
    }
}