通过Java计算文件的MD5值实现方式

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.io.FileInputStream;
import java.io.IOException;

public class FileMD5 {
    public static void main(String[] args) {
        // 替换为你的文件路径
        String filePath = "your_file_path";
        
        try {
            // 创建MessageDigest实例，指定MD5算法
            MessageDigest md = MessageDigest.getInstance("MD5");
            
            // 读取文件内容
            FileInputStream fis = new FileInputStream(filePath);
            
            // 定义缓存区大小
            byte[] buffer = new byte[1024];
            int length;
            
            // 循环读取文件内容，并更新摘要数据
            while ((length = fis.read(buffer)) != -1) {
                md.update(buffer, 0, length);
            }
            
            // 完成哈希计算，得到字节数组形式的MD5值
            byte[] digestBytes = md.digest();
            
            // 将字节数组转换为十六进制字符串
            String md5Hex = bytesToHex(digestBytes);
            
            System.out.println("文件的MD5值是: " + md5Hex);
            
            // 关闭资源
            fis.close();
        } catch (NoSuchAlgorithmException e) {
            System.out.println("不支持MD5算法");
            e.printStackTrace();
        } catch (IOException e) {
            System.out.println("读取文件时发生错误");
            e.printStackTrace();
        }
    }

    // 将字节数组转换为十六进制字符串
    private static String bytesToHex(byte[] bytes) {
        StringBuilder sb = new StringBuilder();
        for (byte b : bytes) {
            String hex = String.format("%02x", b);
            sb.append(hex);
        }
        return sb.toString();
    }
}

public class StringMD5 {
    public static void main(String[] args) {
        String str = "Hello, World!";
        try {
            MessageDigest md = MessageDigest.getInstance("MD5");
            byte[] hashBytes = md.digest(str.getBytes(java.nio.charset.StandardCharsets.UTF_8));
            String md5Hex = bytesToHex(hashBytes);
            System.out.println("字符串的MD5值是: " + md5Hex);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
    }

    private static String bytesToHex(byte[] bytes) {
        // 同上
    }
}

public class MD5Utils {
    public static String getFileMD5(String filePath) throws NoSuchAlgorithmException, IOException {
        MessageDigest md = MessageDigest.getInstance("MD5");
        try (FileInputStream fis = new FileInputStream(filePath)) {
            byte[] buffer = new byte[1024];
            int length;
            while ((length = fis.read(buffer)) != -1) {
                md.update(buffer, 0, length);
            }
            return bytesToHex(md.digest());
        }
    }

    private static String bytesToHex(byte[] bytes) {
        // 同上
    }
}