Java计算文件MD5值(支持大文件)

import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.security.MessageDigest; import org.apache.commons.codec.binary.Hex; import org.apache.commons.codec.digest.DigestUtils; /** *MD5计算工具 */
public class Md5CaculateUtil { /** * 获取一个文件的md5值(可处理大文件) * @return md5 value */
    public static String getMD5(File file) { FileInputStream fileInputStream = null; try { MessageDigest MD5 = MessageDigest.getInstance("MD5"); fileInputStream = new FileInputStream(file); byte[] buffer = new byte[8192]; int length; while ((length = fileInputStream.read(buffer)) != -1) { MD5.update(buffer, 0, length); } return new String(Hex.encodeHex(MD5.digest())); } catch (Exception e) { e.printStackTrace(); return null; } finally { try { if (fileInputStream != null){ fileInputStream.close(); } } catch (IOException e) { e.printStackTrace(); } } } /** * 求一个字符串的md5值 * @param target 字符串 * @return md5 value */
    public static String MD5(String target) { return DigestUtils.md5Hex(target); } public static void main(String[] args) { long beginTime = System.currentTimeMillis(); File file = new File("D:/1/pdi-ce-7.0.0.0-24.zip"); String md5 = getMD5(file); long endTime = System.currentTimeMillis(); System.out.println("MD5:" + md5 + "\n 耗时:" + ((endTime - beginTime) / 1000) + "s"); } }

 修改的一个utils方法：

package hanwl.FileDemo;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Files;
import java.nio.file.StandardOpenOption;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;


public class CalcMD5 {
    
    private static final char[] hexCode = "0123456789ABCDEF".toCharArray();

    public static void main(String[] args) {

        long beginTime = System.currentTimeMillis();
        File file = new File("E:/云舒测试文件/20180628-北大社-中国古文字学通论.pdf");
        //File file = new File("E:/拉鲁斯法汉双解词典(12新)/制作文件库/其他/SJ00040936 拉鲁斯法汉双解词典(内文排版).zip");
        String md5 = calcMD5(file);
        long endTime = System.currentTimeMillis();
        System.out.println("MD5:" + md5 + "\n 耗时:" + ((endTime - beginTime) / 1000) + "s");
    }

    /**
     * 计算文件 MD5
     * @param file
     * @return 返回文件的md5字符串，如果计算过程中任务的状态变为取消或暂停，返回null， 如果有其他异常，返回空字符串
     */
    protected static String calcMD5(File file) {
        try (InputStream stream = Files.newInputStream(file.toPath(), StandardOpenOption.READ)) {
            MessageDigest digest = MessageDigest.getInstance("MD5");
            byte[] buf = new byte[8192];
            int len;
            while ((len = stream.read(buf)) > 0) {
                digest.update(buf, 0, len);
            }
            return toHexString(digest.digest());
        } catch (IOException e) {
            e.printStackTrace();
            return "";
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
            return "";
        }
    }
    
    public static String toHexString(byte[] data) {
          StringBuilder r = new StringBuilder(data.length * 2);
          for (byte b : data) {
              r.append(hexCode[(b >> 4) & 0xF]);
              r.append(hexCode[(b & 0xF)]);
          }
          return r.toString();
      }

}