FileUtil

来源：互联网发布：埃文蕾切尔伍德知乎编辑：程序博客网时间：2024/04/28 23:51
package test;import java.io.BufferedInputStream;import java.io.DataInputStream;import java.io.DataOutputStream;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.FilenameFilter;import java.io.IOException;import java.io.RandomAccessFile;import java.util.ArrayList;import java.util.Arrays;import java.util.Collections;import java.util.Comparator;import java.util.HashSet;import java.util.List;import java.util.Set;import java.util.concurrent.ArrayBlockingQueue;import java.util.concurrent.ThreadPoolExecutor;import java.util.concurrent.TimeUnit;public class FileUtil {private final static short MAGIC = (short) 0xacef;private final static String SUFFIX = ".part";public static void main(String[] args) throws IOException {FileUtil util = new FileUtil();//util.splitBySize("E:\\test\\Spring源码深度解析.pdf", 50 * 1024 * 1024);util.mergePartFiles("E:\\test", "E:\\test\\Spring.pdf");}    /**     * 左填充     */    public static String leftPad(String str, int length, char ch) {        if (str.length() >= length) {            return str;        }        char[] chs = new char[length];        Arrays.fill(chs, ch);        char[] src = str.toCharArray();        System.arraycopy(src, 0, chs, length - src.length, src.length);        return new String(chs);    }    /**     * 删除文件     */    public static boolean delete(String fileName) {        boolean result = false;        File f = new File(fileName);        if (f.exists()) {            result = f.delete();        } else {            result = true;        }        return result;    }    /***     * 递归获取指定目录下的所有的文件（不包括文件夹）     */    public static List<File> getAllFiles(String dirPath) {        File dir = new File(dirPath);        List<File> files = new ArrayList<File>();        if (dir.isDirectory()) {            File[] fileArr = dir.listFiles();            for (int i = 0; i < fileArr.length; i++) {                File f = fileArr[i];                if (f.isFile()) {                    files.add(f);                } else {                    files.addAll(getAllFiles(f.getPath()));                }            }        }        return files;    }    /**     * 获取指定目录下的所有文件(不包括子文件夹)     */    public static List<File> getDirFiles(String dirPath) {        File path = new File(dirPath);        File[] fileArr = path.listFiles();        List<File> files = new ArrayList<File>();        for (File f : fileArr) {            if (f.isFile()) {                files.add(f);            }        }        return files;    }    /**     * 获取指定目录下特定文件后缀名的文件列表(不包括子文件夹)     */    public static List<File> getDirFiles(String dirPath, final String suffix) {        File path = new File(dirPath);        File[] fileArr = path.listFiles(new FilenameFilter() {            public boolean accept(File dir, String name) {                String lowerName = name.toLowerCase();                String lowerSuffix = suffix.toLowerCase();                if (lowerName.endsWith(lowerSuffix)) {                    return true;                }                return false;            }        });        List<File> files = new ArrayList<File>();        for (File f : fileArr) {            if (f.isFile()) {                files.add(f);            }        }        return files;    }    /**     * 追加内容到指定文件     */    public static void append(String fileName, String fileContent) throws IOException {        File f = new File(fileName);        if (f.exists()) {            RandomAccessFile rFile = new RandomAccessFile(f, "rw");            byte[] b = fileContent.getBytes();            long originLen = f.length();            rFile.setLength(originLen + b.length);            rFile.seek(originLen);            rFile.write(b);            rFile.close();        }    }    /**     * 拆分文件     */    public List<String> splitBySize(String fileName, int byteSize) throws IOException {        List<String> parts = new ArrayList<String>();        File file = new File(fileName);        int count = (int) Math.ceil(file.length() / (double) byteSize);        ThreadPoolExecutor threadPool = new ThreadPoolExecutor(        0, count, 1, TimeUnit.SECONDS,                new ArrayBlockingQueue<Runnable>(count));        String destDir = file.getParent();        for (int i = 0; i < count; i++) {            String partFileName = destDir + File.separator + file.getName()                    + leftPad(String.valueOf(i + 1), String.valueOf(count).length(), '0') + SUFFIX;            Fragment f = new Fragment();            f.count = count;            f.order = i + 1;            f.byteSize = byteSize;            f.startPos = i * byteSize;            f.partFile = new File(partFileName);            threadPool.execute(new SplitRunnable(file, f));            parts.add(partFileName);        }        return parts;    }    /**     * 合并文件     */    public void mergePartFiles(String dirPath, String mergeFileName) throws IOException {    List<Fragment> fragments = collectPartFiles(dirPath);    if(fragments.size() < 1){    return;    }        RandomAccessFile randomAccessFile = new RandomAccessFile(mergeFileName, "rw");        Fragment f = fragments.get(fragments.size() -1);        randomAccessFile.setLength(f.startPos + f.byteSize);        randomAccessFile.close();        ThreadPoolExecutor threadPool = new ThreadPoolExecutor(                0, fragments.size(), 1, TimeUnit.SECONDS,                new ArrayBlockingQueue<Runnable>(fragments.size()));        for (int i = 0; i < fragments.size(); i++) {            threadPool.execute(new MergeRunnable(mergeFileName, fragments.get(i)));        }    }        public List<Fragment> collectPartFiles(String dirPath) throws IOException{    List<File> partFiles = getDirFiles(dirPath);    Set<Fragment> fragments = new HashSet<Fragment>();    for(File file : partFiles){    DataInputStream in = new DataInputStream(new FileInputStream(file));    if(in.available() < 14) continue;    short magic = in.readShort();    if(magic != MAGIC) continue;    int count = in.readInt();    int order = in.readInt();    int size = in.readInt();    if(size + 14 != file.length()) continue;    Fragment fragment = new Fragment();    fragment.byteSize = size;    fragment.count = count;    fragment.order = order;    fragment.partFile = file;    fragments.add(fragment);    in.close();    }    List<Fragment> list = new ArrayList<Fragment>();    list.addAll(fragments);    Collections.sort(list, new Comparator<Fragment>(){@Overridepublic int compare(Fragment o1, Fragment o2) {return o1.order - o2.order;}    });    long startPos = 0;    for(int i = 0; i < list.size(); i++){    Fragment f = list.get(i);    if(f.order != i + 1){    return Collections.emptyList();    }    if(f.count != list.size()){    return Collections.emptyList();    }    f.startPos = startPos;    startPos = startPos + f.byteSize;    }    return list;    }    public static class Fragment {    private int count;    private int order;    private long startPos;    private int byteSize;    private File partFile;    public int getCount() {return count;}public void setCount(int count) {this.count = count;}public int getOrder() {return order;}public void setOrder(int order) {this.order = order;}public long getStartPos() {return startPos;}public void setStartPos(long startPos) {this.startPos = startPos;}public int getByteSize() {return byteSize;}public void setByteSize(int byteSize) {this.byteSize = byteSize;}public File getPartFile() {return partFile;}public void setPartFile(File partFile) {this.partFile = partFile;}@Overridepublic int hashCode() {final int prime = 31;long result = 1;result = prime * result + byteSize;result = prime * result + count;result = prime * result + order;result = prime * result + startPos;return (int)result;}@Overridepublic boolean equals(Object obj) {if (this == obj)return true;if (obj == null)return false;if (getClass() != obj.getClass())return false;Fragment other = (Fragment) obj;if (byteSize != other.byteSize)return false;if (count != other.count)return false;if (order != other.order)return false;if (startPos != other.startPos)return false;return true;}    }        /**     * 分割处理Runnable     */    private class SplitRunnable implements Runnable {        File originFile;        Fragment fragment;        public SplitRunnable(File originFile, Fragment fragment) {            this.fragment = fragment;            this.originFile = originFile;        }        public void run() {            RandomAccessFile rFile;            DataOutputStream os;            try {                rFile = new RandomAccessFile(originFile, "r");                byte[] b = new byte[fragment.byteSize];                os = new DataOutputStream(new FileOutputStream(fragment.partFile));                os.writeShort(MAGIC);                os.writeInt(fragment.count);                os.writeInt(fragment.order);                rFile.seek(fragment.startPos);                int s = rFile.read(b);                os.writeInt(s);                os.write(b, 0, s);                os.flush();                os.close();            } catch (IOException e) {                e.printStackTrace();            }        }    }    /**     * 合并处理Runnable     */    private class MergeRunnable implements Runnable {        String mergeFileName;        Fragment fragment;        public MergeRunnable(String mergeFileName, Fragment fragment) {            this.mergeFileName = mergeFileName;            this.fragment = fragment;        }        public void run() {            RandomAccessFile rFile;            try {                rFile = new RandomAccessFile(mergeFileName, "rw");                rFile.seek(fragment.startPos);                BufferedInputStream bis = new BufferedInputStream(new FileInputStream(fragment.partFile));                byte[] buf = new byte[2048];                bis.read(buf, 0, 14);                int len = 0;                while((len = bis.read(buf)) > 0){                rFile.write(buf, 0, len);                }                bis.close();                rFile.close();            } catch (IOException e) {                e.printStackTrace();            }        }    }}
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