言归正传，直接看代码

public class RemoveDuplicateFiles {public static void main(String[] args) throws IOException {String directoryPath = "D:\\dir";List<File> allFiles = getAllFiles(directoryPath);removeDuplicateFile(allFiles);}private static void removeDuplicateFile(List<File> allFiles) throws IOException {// 按文件大小排序allFiles.sort(Comparator.comparing(File::length));// 找出文件大小相同的文件for (int i = 0; i < allFiles.size(); i++) {File file = allFiles.get(i);byte[] fileContent = getFileContent(file);for (int j = i+1;j<allFiles.size();j++){File file1 = allFiles.get(j);// 如果文件大小相同则比较内容if (file.length() == file1.length()){byte[] fileContent1 = getFileContent(file1);// 比较字节内容，如果内容也想通，则删除重复的文件if (Arrays.equals(fileContent,fileContent1)){file1.delete();}}else {i=j;break;}}}}private static byte[] getFileContent(File file) throws IOException {Path path = Paths.get(file.getAbsolutePath());return Files.readAllBytes(path);}private static List<File> getAllFiles(String directoryPath) {List<File> allFiles = new ArrayList<>();File directory = new File(directoryPath);File[] files = directory.listFiles();for (File file : files) {if (file.isDirectory()){String absolutePath = file.getAbsolutePath();List<File> allFiles1 = getAllFiles(absolutePath);allFiles.addAll(allFiles1);}else {allFiles.add(file);}}return allFiles;}
}