Apache Commons Codec — 加密与编码

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>org.apache.commons</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) {  
      logger.error("md5 error", e);  
    }  
    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) {  
      logger.error("sha256 error", e);  
    }  
    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) {  
      logger.error("base64 error", e);  
    }

    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