Java操作文件

痛定思痛。 2022-07-13 01:49 143阅读 0赞

需求如下:
        一个文件夹有很多图片,图片名字混杂,要求把当前文件夹所有的文件复制到另一个文件目录下,但是名字要从从1开始,按照时间或大小或者名称
        先后排序

code:

import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileOutputStream;
    import java.io.InputStream;
    import java.util.Arrays;
    import java.util.Collections;
    import java.util.Comparator;
    import java.util.List;
    
    /** * Created by simon on 16-12-19. */
    @SuppressWarnings("Duplicates")
    public class Demo { 
    
        public static void main(String ss[]) {
            File file = new File("/home/simon/桌面/我们的故事/img");
            orderByDate("/home/simon/桌面/我们的故事/img");
            File[] tempList = file.listFiles();
            for (int i = 0; i < tempList.length; i++) {
                File temp = tempList[i];
                copyFile(temp.getPath(), "/home/simon/桌面/我们的故事/gen/" + (i + 1) + getFileSux(temp));
            }
    
        }
    
        //获取文件后缀
        public static String getFileSux(File f) {
            String fileName = f.getName();
            String prefix = fileName.substring(fileName.lastIndexOf("."));
            return prefix;
        }
    
    
        //复制文件
        public static void copyFile(String oldPath, String newPath) {
            try {
                int bytesum = 0;
                int byteread = 0;
                File oldfile = new File(oldPath);
                if (oldfile.exists()) { //文件存在时
                    InputStream inStream = new FileInputStream(oldPath); //读入原文件
                    FileOutputStream fs = new FileOutputStream(newPath);
                    byte[] buffer = new byte[1444];
                    while ((byteread = inStream.read(buffer)) != -1) {
                        bytesum += byteread; //字节数 文件大小
                        fs.write(buffer, 0, byteread);
                    }
                    inStream.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    
        //重命名
        public static void renameFile(String path, String oldname, String newname) {
            if (!oldname.equals(newname)) {
       //新的文件名和以前文件名不同时,才有必要进行重命名
                File oldfile = new File(path + "/" + oldname);
                File newfile = new File(path + "/" + newname);
                if (!oldfile.exists()) {
                    return;//重命名文件不存在
                }
                if (newfile.exists())//若在该目录下已经有一个文件和新文件名相同，则不允许重命名
                    System.out.println(newname + "已经存在！");
                else {
                    oldfile.renameTo(newfile);
                }
            } else {
                System.out.println("新文件名和旧文件名相同...");
            }
        }
    
        //按照文件大小排序
        public static void orderByLength(String fliePath) {
            List<File> files = Arrays.asList(new File(fliePath).listFiles());
            Collections.sort(files, new Comparator<File>() {
                public int compare(File f1, File f2) {
                    long diff = f1.length() - f2.length();
                    if (diff > 0)
                        return 1;
                    else if (diff == 0)
                        return 0;
                    else
                        return -1;
                }
    
                public boolean equals(Object obj) {
                    return true;
                }
            });
            for (File f : files) {
                if (f.isDirectory()) continue;
                System.out.println(f.getName() + ":" + f.length());
            }
        }
    
        //按照文件名称排序
        public static void orderByName(String fliePath) {
            List files = Arrays.asList(new File(fliePath).listFiles());
            Collections.sort(files, new Comparator<File>() {
                @Override
                public int compare(File o1, File o2) {
                    if (o1.isDirectory() && o2.isFile())
                        return -1;
                    if (o1.isFile() && o2.isDirectory())
                        return 1;
                    return o1.getName().compareTo(o2.getName());
                }
            });
        }
    
        //按日期排序
        public static void orderByDate(String fliePath) {
            File file = new File(fliePath);
            File[] fs = file.listFiles();
            Arrays.sort(fs, new Comparator<File>() {
                public int compare(File f1, File f2) {
                    long diff = f1.lastModified() - f2.lastModified();
                    if (diff > 0)
                        return 1;
                    else if (diff == 0)
                        return 0;
                    else
                        return -1;
                }
    
                public boolean equals(Object obj) {
                    return true;
                }
            });
        }
    
    }