Java使用io流和多线程实现切割文件,合并文件

我就是我 2022-04-10 04:38 594阅读 0赞

##  主体类 ##

package com.file;
    
    import com.sun.glass.ui.Size;
    
    import java.io.BufferedInputStream;
    import java.io.BufferedOutputStream;
    import java.io.Closeable;
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileNotFoundException;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.RandomAccessFile;
    import java.io.SequenceInputStream;
    import java.util.ArrayList;
    import java.util.List;
    import java.util.Vector;
    import java.util.concurrent.ExecutorService;
    import java.util.concurrent.Executors;
    import java.util.concurrent.ThreadPoolExecutor;
    
    /**
     * @program: Maven
     * @description: 测试2
     * @author: hw
     * @create: 2018-12-25 00:38
     **/
    public class Demo2 {
        //文件的路径
        private String filePath;
        //文件名
        private String fileName;
        //文件大小
        private long length;
        //块数
        private int size;
        //每块的大小
        private long blockSize;
        //分割后的存放目录
        private String destBlockPath;
        //每块的名称
        private List<String> blockPath;
    
        public Demo2() {
            blockPath = new ArrayList<String>();
        }
    
        public Demo2(String filePath, String destBlockPath) {
            this(filePath, destBlockPath, 1024 * 1024 * 100);
        }
    
        public Demo2(String filePath, String destBlockPath, long blockSize) {
            this();
            this.filePath = filePath;
            this.destBlockPath = destBlockPath;
            this.blockSize = blockSize;
            init();
        }
    
    
        /**
         * @Description: 初始化操作 计算 块数、确定文件名
         * @Param: []
         * @return: void
         * @Author: hw
         * @Date: 2018/12/25
         */
        public void init() {
            File file = null;
            //如果为空或者路径为文件夹则返回
            if (filePath == null || !((file = new File(filePath)).exists()) || file.isDirectory())
                return;
            //文件名
            this.fileName = file.getName();
            //计算分割数量    实际大小    每块大小
            this.length = file.length();
            //每块大小
            if (this.blockSize > length) {
                this.blockSize = length;
            }
            //确定分割数量
            size = (int) Math.ceil(length * 1.0 / this.blockSize);
            //确定分割文件的路径
            initPathName();
        }
    
        private void initPathName() {
            for (int i = 0; i < size; i++) {
                this.blockPath.add(destBlockPath + "/" + this.fileName + ".part" + i);
            }
        }
    
        /**
         * 文件的分割
         * 0)、第几块
         * 1、起始位置
         * 2、实际大小
         * 分割文件存放目录
         */
        boolean exeFlag = true;
    
        public void split() {
            long beginPos = 0;  //起始点
            long actualBlockSize = blockSize; //实际大小
            //计算所有块的大小、位置、索引
            for (int i = 0; i < size; i++) {
                if (i == size - 1) { //最后一块
                    actualBlockSize = length - beginPos;
                }
    
                spiltDetail(i, beginPos, actualBlockSize);
                //多线程版本
    //            new Run(i,beginPos,actualBlockSize,filePath,blockPath).start();
                beginPos += actualBlockSize; //本次的终点，下一次的起点
            }
        }
    
    
    
        public static void main(String[] args) {
            //1024 * 30 表示按照每块30Kb大小分割
            final Demo2 split = new Demo2("D:/BaiduNetdiskDownload/123.mp4", "D:/BaiduNetdiskDownload/123/", 1024 * 200 * 1024);
            System.out.println(split.size);
            long l = System.currentTimeMillis();
    
            split.split();
    //        split.merge("D:/BaiduNetdiskDownload/123/123.mp4");
    
        }
    
        /**
         * @Description: 文件分割
         * @Param: [idx, beginPos, actualBlockSize]
         * @return: void
         * @Author: hw
         * @Date: 2018/12/25
         */
        private void spiltDetail(int idx, long beginPos, long actualBlockSize) {
            //1、创建源
            File src = new File(this.filePath);  //源文件
            File dest = new File(this.blockPath.get(idx)); //目标文件
            //2、选择流
            RandomAccessFile raf = null;  //输入流
            BufferedOutputStream bos = null; //输出流
            try {
                raf = new RandomAccessFile(src, "r");
                bos = new BufferedOutputStream(new FileOutputStream(dest));
                //读取文件
                raf.seek(beginPos);
                //缓冲区
                byte[] flush = new byte[1024<<2];
                //接收长度
                int len = 0;
                while (-1 != (len = raf.read(flush))) {
                    if (actualBlockSize - len >= 0) { //查看是否足够
                        //写出
                        bos.write(flush, 0, len);
                        actualBlockSize -= len; //剩余量
                    } else { //写出最后一次的剩余量
                        bos.write(flush, 0, (int) actualBlockSize);
                        break;
                    }
                }
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                this.close(bos, raf);
            }
        }
    
    
        /**
         * 文件的合并
         */
        public void merge(String destPath) {
            //创建源
            File dest = new File(destPath);
            //选择流
            BufferedOutputStream bos = null; //输出流
            SequenceInputStream sis = null;//输入流
            //创建一个容器
            Vector<InputStream> vi = new Vector<InputStream>();
            try {
                for (int i = 0; i < this.blockPath.size(); i++) {
                    vi.add(new BufferedInputStream(new FileInputStream(new File(this.blockPath.get(i)))));
                }
                bos = new BufferedOutputStream(new FileOutputStream(dest, true)); //追加
                sis = new SequenceInputStream(vi.elements());
                //缓冲区
                byte[] flush = new byte[1024<<2];
                //接收长度
                int len = 0;
                while (-1 != (len = sis.read(flush))) {
                    bos.write(flush, 0, len);
                }
                bos.flush();
                this.close(sis);
            } catch (Exception e) {
            } finally {
                this.close(bos);
            }
        }
    
        /关闭流
        public static void close(Closeable... io) {
            for (Closeable temp : io) {
                try {
                    if (null != temp) {
                        temp.close();
                    }
                } catch (Exception e) {
                }
            }
    
        }
    
        /**
         * 使用泛型方法
         */
        public static <T extends Closeable> void closeAll(T... io) {
            for (Closeable temp : io) {
                try {
                    if (null != temp) {
                        temp.close();
                    }
                } catch (Exception e) {
                }
            }
        }
    
    
    }

## 线程类 ##

package com.file;
    
    import java.io.BufferedOutputStream;
    import java.io.Closeable;
    import java.io.File;
    import java.io.FileNotFoundException;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.RandomAccessFile;
    import java.util.List;
    
    /**
     * @program: Maven
     * @description:
     * @author: hw
     * @create: 2018-12-25 01:20
     **/
    public class Run extends Thread {
        private int i;
        private long beginPos;
        private long actualBlockSize;
        private String filePath;
        //每块的名称
        private List<String> blockPath;
    
        public int getI() {
            return i;
        }
    
        public void setI(int i) {
            this.i = i;
        }
    
        public long getBeginPos() {
            return beginPos;
        }
    
        public void setBeginPos(long beginPos) {
            this.beginPos = beginPos;
        }
    
        public long getActualBlockSize() {
            return actualBlockSize;
        }
    
        public void setActualBlockSize(long actualBlockSize) {
            this.actualBlockSize = actualBlockSize;
        }
    
        public String getFilePath() {
            return filePath;
        }
    
        public void setFilePath(String filePath) {
            this.filePath = filePath;
        }
    
        public List<String> getBlockPath() {
            return blockPath;
        }
    
        public void setBlockPath(List<String> blockPath) {
            this.blockPath = blockPath;
        }
    
        public Run(int i, long beginPos, long actualBlockSize, String filePath, List<String> blockPath) {
            this.i = i;
            this.beginPos = beginPos;
            this.actualBlockSize = actualBlockSize;
            this.filePath = filePath;
            this.blockPath = blockPath;
        }
    
        @Override
        public void run() {
            System.out.println(1);
            //1、创建源
            File src = new File(this.filePath);  //源文件
            File dest = new File(this.blockPath.get(i)); //目标文件
            //2、选择流
            RandomAccessFile raf = null;  //输入流
            BufferedOutputStream bos = null; //输出流
            try {
                raf = new RandomAccessFile(src, "r");
                bos = new BufferedOutputStream(new FileOutputStream(dest));
                //读取文件
                raf.seek(beginPos);
                //缓冲区
                byte[] flush = new byte[1024<<2];
                //接收长度
                int len = 0;
                while (-1 != (len = raf.read(flush))) {
                    if (actualBlockSize - len >= 0) { //查看是否足够
                        //写出
                        bos.write(flush, 0, len);
                        actualBlockSize -= len; //剩余量
                    } else { //写出最后一次的剩余量
                        bos.write(flush, 0, (int) actualBlockSize);
                        break;
                    }
                }
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                this.close(bos, raf);
                System.out.println(2);
            }
        }
    
        /关闭流
        public static void close(Closeable... io) {
            for (Closeable temp : io) {
                try {
                    if (null != temp) {
                        temp.close();
                    }
                } catch (Exception e) {
                }
            }
    
        }
    
        /**
         * 使用泛型方法
         */
        public static <T extends Closeable> void closeAll(T... io) {
            for (Closeable temp : io) {
                try {
                    if (null != temp) {
                        temp.close();
                    }
                } catch (Exception e) {
                }
            }
        }
    
    }

## 如果电脑磁盘和性能都比较好的话可以试试多线程版本,如不然的话就用单线程的就够了 ##