commons-codec是Apache开源组织提供的用于摘要运算、编码的包。在该包中主要分为四类加密：BinaryEncoders、DigestEncoders、LanguageEncoders、NetworkEncoders。

今天就为大家介绍一下如何用commons-codec包完成常见的编码、摘要运算。

Base64

示例代码：

@Test
public void testBase64()
{
   System.out.println("==============Base64================");
   byte[] data = "jianggujin".getBytes();
   Base64 base64 = new Base64();
   String encode = base64.encodeAsString(data);
   System.out.println(encode);
   System.out.println(new String(base64.decode(encode)));
}

运行结果：

==============Base64================
amlhbmdndWppbg==
jianggujin

MD5摘要运算

示例代码：

@Test
public void testMD5()
{
   System.out.println("==============MD5================");
   String result = DigestUtils.md5Hex("jianggujin");
   System.out.println(result);
}

运行结果：

acab4efdfd3b8efcdec37fe160d7be0e

SHA等摘要运算和MD5类似。

URLCodec

示例代码：

@Test
public void testURLCodec() throws Exception
{
   System.out.println("==============URLCodec================");
   URLCodec codec = new URLCodec();
   String data = "蒋固金";
   String encode = codec.encode(data, "UTF-8");
   System.out.println(encode);
   System.out.println(codec.decode(encode, "UTF-8"));
}

运行结果：

==============URLCodec================
%E8%92%8B%E5%9B%BA%E9%87%91
蒋固金

完整示例代码：

package com.gujin.codec;

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.codec.digest.DigestUtils;
import org.apache.commons.codec.net.URLCodec;
import org.junit.Test;

public class CodecTest
{
   @Test
   public void testBase64()
   {
      System.out.println("==============Base64================");
      byte[] data = "jianggujin".getBytes();
      Base64 base64 = new Base64();
      String encode = base64.encodeAsString(data);
      System.out.println(encode);
      System.out.println(new String(base64.decode(encode)));
   }

   @Test
   public void testMD5()
   {
      System.out.println("==============MD5================");
      String result = DigestUtils.md5Hex("jianggujin");
      System.out.println(result);
   }

   @Test
   public void testURLCodec() throws Exception
   {
      System.out.println("==============URLCodec================");
      URLCodec codec = new URLCodec();
      String data = "蒋固金";
      String encode = codec.encode(data, "UTF-8");
      System.out.println(encode);
      System.out.println(codec.decode(encode, "UTF-8"));
   }
}