常用文件工具类FileTools

package cn.com.wind.src.utils;

import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.collect.Interner;
import com.google.common.collect.Interners;
import com.google.common.io.Files;
import org.springframework.util.DigestUtils;

import java.io.*;
import java.util.ArrayList;
import java.util.List;

/**
 * @Author qymeng
 * @Date 2022/7/28
 * @Description
 */

public class FileTools {

    private static ObjectMapper mapper = new ObjectMapper();

    private static Interner<String> stringPool = Interners.newWeakInterner();

    static {
        mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
    }

    private FileTools() {
    }

    /**
     * 读取byte[]文件内容
     * @param fileBytes
     * @return
     */
    public static String readFile(byte[] fileBytes) {
        StringBuilder stringBuilder = null;
        try {
            if (fileBytes!=null) {
                InputStream inputStream = new ByteArrayInputStream(fileBytes);
                InputStreamReader streamReader = new InputStreamReader(inputStream);
                BufferedReader reader = new BufferedReader(streamReader);
                String line;
                stringBuilder = new StringBuilder();
                while ((line = reader.readLine()) != null) {
                    stringBuilder.append(line);
                }
                reader.close();
                inputStream.close();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return String.valueOf(stringBuilder);
    }

    /**
     * 写文件
     * @param file
     * @param fileContent
     */
    public static void writeFile(File file, byte[] fileContent) {
        try {
            ensureParentExists(file);
            Files.asByteSink(file).write(fileContent);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void writeFile(String filePath, byte[] fileContent){
        writeFile(new File(filePath), fileContent);
    }

    public static void ensureParentExists(File file) throws IOException {
        if (!file.exists()) {
            ensureParentExists(file.getParentFile());
            Files.createParentDirs(file);
        }
    }

    /**
     * byte数组转文件
     *
     * @param bytes
     * @return
     * @throws IOException
     */
    public static File byteToFile(byte[] bytes, String path) {
        File dir = new File(path);
        if (!dir.exists() && !dir.isDirectory()) {//判断文件目录是否存在
            dir.mkdirs();
        }

        File file = new File(path);
        FileOutputStream fout = null;
        try {
            fout = new FileOutputStream(file);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        BufferedOutputStream bout = new BufferedOutputStream(fout);
        try {
            bout.write(bytes);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return file;
    }

    /**
     * 删除文件或目录,若是文件,则直接删除,若是目录,则递归删除目录下的所有文件后再删除目录
     *
     * @param fileOrDir fileOrDir
     * @return
     */
    public static boolean delDirAndFile(File fileOrDir) {
        if (fileOrDir.isFile()) {
            return fileOrDir.delete();
        }
        File[] subFiles = fileOrDir.listFiles();
        if (subFiles != null) {
            for (File file : subFiles) {
                delDirAndFile(file);
            }
        }
        return fileOrDir.delete();
    }


    /**
     * 寻找固定后缀名的文件
     *
     * @param dir
     * @param suffix
     * @return
     */
    public static List<File> findFiles(File dir, String suffix) {
        List<File> files = new ArrayList<>();
        if (dir.exists()
                && dir.isDirectory()) {
            for (File file : dir.listFiles()) {
                if (file.isDirectory()) {
                    files.addAll(findFiles(file, suffix));
                } else {
                    if (suffix != null) {
                        if (file.getName().endsWith(suffix)) {
                            files.add(file);
                        }
                    } else {
                        files.add(file);
                    }
                }
            }
        }
        return files;
    }

    /**
     * 得到无扩展名的文件名
     *
     * @param filename
     * @return
     */
    public static String getFileNameNoEx(String filename) {
        if ((filename != null) && (filename.length() > 0)) {
            int dot = filename.lastIndexOf('.');
            if ((dot > -1) && (dot < (filename.length()))) {
                return filename.substring(0, dot);
            }
        }
        return filename;
    }


    public static String calcMd5(Object source) throws IOException {
        return DigestUtils.md5DigestAsHex(mapper.writeValueAsBytes(source));
    }


    public static <T> T deserialize(String content, Class<T> type) throws IOException {
        return mapper.readValue(content, type);
    }

    public static <T> T deserialize(File file, Class<T> type) throws IOException {
        synchronized (stringPool.intern(file.getName())) {
            return mapper.readValue(file, type);
        }
    }

    public static void serialize(File file, Object value) throws IOException {
        ensureParentExists(file);
        synchronized (stringPool.intern(file.getName())) {
            mapper.writerWithDefaultPrettyPrinter().writeValue(file, value);
        }
    }

    public static String charset(String path) {
        String charset = "GBK";
        byte[] first3Bytes = new byte[3];
        try (BufferedInputStream bis = new BufferedInputStream(new FileInputStream(path))) {
            boolean checked = false;

            bis.mark(0); // 读者注： bis.mark(0);修改为 bis.mark(100);我用过这段代码，需要修改上面标出的地方。
            // Wagsn注：不过暂时使用正常，遂不改之
            int read = bis.read(first3Bytes, 0, 3);
            if (read == -1) {
                return charset; // 文件编码为 ANSI
            } else if (first3Bytes[0] == (byte) 0xFF && first3Bytes[1] == (byte) 0xFE) {
                charset = "UTF-16LE"; // 文件编码为 Unicode
                checked = true;
            } else if (first3Bytes[0] == (byte) 0xFE && first3Bytes[1] == (byte) 0xFF) {
                charset = "UTF-16BE"; // 文件编码为 Unicode big endian
                checked = true;
            } else if (first3Bytes[0] == (byte) 0xEF && first3Bytes[1] == (byte) 0xBB
                    && first3Bytes[2] == (byte) 0xBF) {
                charset = "UTF-8"; // 文件编码为 UTF-8
                checked = true;
            }
            bis.reset();
            if (!checked) {
                while ((read = bis.read()) != -1) {
                    if (read >= 0xF0) {
                        break;
                    }
                    if (0x80 <= read && read <= 0xBF) // 单独出现BF以下的，也算是GBK
                    {
                        break;
                    }
                    if (0xC0 <= read && read <= 0xDF) {
                        read = bis.read();
                        if (0x80 <= read && read <= 0xBF) // 双字节 (0xC0 - 0xDF)
                        // (0x80 - 0xBF),也可能在GB编码内
                        {
                            continue;
                        } else {
                            break;
                        }
                    } else if (0xE0 <= read && read <= 0xEF) { // 也有可能出错，但是几率较小
                        read = bis.read();
                        if (0x80 <= read && read <= 0xBF) {
                            read = bis.read();
                            if (0x80 <= read && read <= 0xBF) {
                                charset = "UTF-8";
                                break;
                            } else {
                                break;
                            }
                        } else {
                            break;
                        }
                    }
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return charset;
    }
}