各类Hash算法-Java版

以下Hash算法经常被用在数据的签名中，这里整理了一下Java版sha-x和md5算法

import java.io.UnsupportedEncodingException;
import java.security.NoSuchAlgorithmException;
import java.security.MessageDigest;

public class SHA_1 {
    public static void main(String[] args) {
        String v0_1, v0_2, v0_3;
        v0_1 = MD5("测试qwerty1234");
        System.out.println("MD5加密：" + v0_1.toUpperCase());
        v0_2 = SHA1("测试qwerty1234");
        System.out.println("SHA1加密：" + v0_2.toUpperCase());
        v0_3 = SHA256("测试qwerty1234");
        System.out.println("SHA256加密：" + v0_3.toUpperCase());
    }

    public final static String MD5(String plaintext) {
        char hexDigits[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
        try {
            MessageDigest mdTemp = MessageDigest.getInstance("MD5");
            mdTemp.update(plaintext.getBytes("UTF-8"));    // 不设置编码的话中文加密会错误
            byte tmp[] = mdTemp.digest();
            char str[] = new char[16 * 2];
            int k = 0;
            for (int i = 0; i < 16; i++) {
                str[k++] = hexDigits[tmp[i] >>> 4 & 0xf];
                str[k++] = hexDigits[tmp[i] & 0xf];
            }
            return new String(str);
        } catch (UnsupportedEncodingException | NoSuchAlgorithmException e) {
            return null;
        }
    }

    public final static String SHA1(String plaintext) {
        try {
            MessageDigest digest = MessageDigest.getInstance("SHA-1");
            digest.update(plaintext.getBytes("UTF-8"));    // 不设置编码的话中文加密会错误
            byte messageDigest[] = digest.digest();
            StringBuffer hexString = new StringBuffer();
            for (int i = 0; i < messageDigest.length; i++) {
                String shaHex = Integer.toHexString(messageDigest[i] & 0xFF);
                if (shaHex.length() < 2) {
                    hexString.append(0);
                }
                hexString.append(shaHex);
            }
            return hexString.toString();
        } catch (UnsupportedEncodingException | NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return "";
    }

    public final static String SHA256(String plaintext) {
        try {
            MessageDigest digest = MessageDigest.getInstance("SHA-256");
            digest.update(plaintext.getBytes("UTF-8"));    // 不设置编码的话中文加密会错误
            byte messageDigest[] = digest.digest();
            StringBuffer hexString = new StringBuffer();
            for (int i = 0; i < messageDigest.length; i++) {
                String shaHex = Integer.toHexString(messageDigest[i] & 0xFF);
                if (shaHex.length() < 2) {
                    hexString.append(0);
                }
                hexString.append(shaHex);
            }
            return hexString.toString();
        } catch (UnsupportedEncodingException | NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return "";
    }

}

输出

MD5加密：A93D78B74CC3472A98EAC49F3B9996ED
SHA1加密：36565A8732E345BB785BEA18DD5924B637062627
SHA256加密：C45D2D155D599DF32272B1AC75CDF6799AEB584FD24FDBC5FB0620B946BE7DAC