Returns the MD5 of the specified bytes - Java Security

Java examples for Security:MD5

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Description

Returns the MD5 of the specified bytes

Demo Code


//package com.java2s;
import java.io.File;
import java.io.FileInputStream;

import java.io.IOException;
import java.io.InputStream;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class Main {
    public static void main(String[] argv) throws Exception {
        byte[] data = new byte[] { 34, 35, 36, 37, 37, 37, 67, 68, 69 };
        System.out.println(md5(data));
    }//ww  w .j  av  a  2  s  . c  om

    /**
     * Returns the MD5 of the specified bytes
     *
     * @param data
     *            A byte array
     * @return the MD5 sum
     */
    public static final String md5(final byte[] data) {
        if (null == data || data.length <= 0) {
            throw new IllegalArgumentException("empty data");
        }

        try {
            final MessageDigest md = MessageDigest.getInstance("MD5");
            return toHexString(md.digest(data));
        } catch (final NoSuchAlgorithmException e) {
            return null;
        }
    }

    /**
     * Returns the MD5 of the specified string
     *
     * @param data
     *            A string value
     * @return the MD5 sum
     */
    public static final String md5(final String data) {
        if (null == data) {
            throw new IllegalArgumentException("null string");
        }

        try {
            final MessageDigest md = MessageDigest.getInstance("MD5");
            return toHexString(md.digest(data.getBytes()));
        } catch (final NoSuchAlgorithmException e) {
            return null;
        }
    }

    /**
     * Returns the MD5 of the specified file
     *
     * @param file
     *            A file
     * @return the MD5 sum of the file
     * @throws FileNotFoundException
     * @throws IOException
     */
    public static String md5(final File file) throws IOException {
        if (null == file || !file.exists()) {
            throw new IllegalArgumentException("file is unavailable");
        }

        final byte[] buf = new byte[1024 * 8];

        try {
            final MessageDigest md = MessageDigest.getInstance("MD5");

            InputStream is = null;

            try {
                is = new FileInputStream(file);

                for (int n = 0; (n = is.read(buf)) != -1;) {
                    md.update(buf, 0, n);
                }
            } finally {
                if (is != null) {
                    try {
                        is.close();
                    } catch (IOException e) {
                    }
                    is = null;
                }
            }

            return new BigInteger(1, md.digest()).toString(16);
        } catch (final NoSuchAlgorithmException e) {
            return null;
        }
    }

    /**
     * Returns the specified data as hex sequence
     *
     * @param data
     *            The data
     * @return a hex string
     */
    public static String toHexString(byte[] data) {
        final int n = data.length;
        final StringBuilder hex = new StringBuilder();

        for (int i = 0; i < n; i++) {
            final byte b = data[i];
            hex.append(String.format("%02x", b & 0xff));
        }

        return hex.toString();
    }
}

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