BridgeLi's Blog

明天就是十一假期了，公司也没多大事，刷知乎，看到有人吐槽曾经的一个合作伙伴连 md5 都写不对，告诉对方写错了，对方顾头不顾腚的修，还是没修对，然后测了一下自己写的想亏写对了，不然又遗留 bug 了，不过看下面评论，有人提到 Apache Commons Codec 里面都已经写好了，看了一下确实，反正也无聊，也写不了大文章，写着玩玩。

1. 先看自己手写的 md5 // 今后大家不要这么写了，太傻了

package cn.bridgeli.demo;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * Created by bridgeli on 2019/7/12.
 */
public class EncryptUtils {

    private static Logger logger = LoggerFactory.getLogger(EncryptUtils.class);

    private EncryptUtils() {
    }

    public static String getMD5(String content) {

        if (null == content) {
            return "";
        }

        MessageDigest messageDigest = null;
        try {
            messageDigest = MessageDigest.getInstance("md5");
        } catch (NoSuchAlgorithmException e) {
            logger.error("md5 error", e);
        }
        if (null == messageDigest) {
            return "";
        }
        messageDigest.update(content.getBytes());
        byte[] bytes = messageDigest.digest();
        StringBuilder stringBuilder = new StringBuilder();
        for (byte b : bytes) {
            String str = Integer.toHexString(b & 0xFF);
            if (str.length() == 1) {
                stringBuilder.append("0");
            }
            stringBuilder.append(str);
        }
        String result = stringBuilder.toString();

        return result;
    }
}

2. 借助别人写好的工具类实现

先引入依赖

        <dependency>
            <artifactId>commons-codec</artifactId>
            <groupId>commons-codec</groupId>
            <version>1.9</version>
        </dependency>

具体实现

package cn.bridgeli.demo;

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.codec.binary.Hex;
import org.apache.commons.codec.digest.DigestUtils;
import org.junit.Test;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

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

/**
 * Created by bridgeli on 2019/9/22.
 */
public class DigestUtilsTest {

    @Test
    public void testMd5() {
        String string = DigestUtils.md5Hex("test");
        System.out.println(string);

        MessageDigest md = null;
        try {
            md = MessageDigest.getInstance("MD5");
        } catch (NoSuchAlgorithmException e) {
            // 日志
        }
        byte[] md5Bytes = md.digest("test".getBytes());
        System.out.println(Hex.encodeHex(md5Bytes));

    }

    @Test
    public void testSHA256() {
        MessageDigest md = null;
        try {
            md = MessageDigest.getInstance("SHA-256");
        } catch (NoSuchAlgorithmException e) {
            // 日志
        }
        byte[] md5Bytes = md.digest("test".getBytes());
        System.out.println(Hex.encodeHex(md5Bytes));

        System.out.println(DigestUtils.sha256Hex("test"));

    }

    @Test
    public void testBASE64() {
        BASE64Encoder encoder = new BASE64Encoder();
        String enStr = encoder.encode("test".getBytes());
        System.out.println(enStr);
        BASE64Decoder decoder = new BASE64Decoder();
        try {
            System.out.println(new String(decoder.decodeBuffer(enStr)));
        } catch (IOException e) {
            // 日志
        }

        byte[] result = Base64.encodeBase64("test".getBytes());
        System.out.println(new String(result));
        System.out.println(new String(Base64.decodeBase64(result)));

    }

}

最后想说的是，Apache commons 中有各种各样好用的工具类，没事的时候，翻翻就会有大收获，然后将来写代码的时候，不知道速度能提升多少倍

参考资料：https://www.jianshu.com/p/cf5d511d2db0