Java：Base64编码解码

Base64编码解码已经加入Java 8 类库的标准。
使用文档：https://www.runoob.com/java/java8-base64.html

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编码解码示例：

import java.util.Base64;
import java.util.Base64.Decoder;

public class Test {
  public static void main(String[] args) throws Exception {
    String str = "锄禾日当午，汗滴禾下土。\n谁知盘中餐，粒粒皆辛苦。";
    
    String base64_1 = Base64.getEncoder().encodeToString(str.getBytes("utf-8"));
    System.out.println(base64_1);
    System.out.println("*******");
    
    String base64_2 = Base64.getMimeEncoder().encodeToString(str.getBytes("utf-8"));
    System.out.println(base64_2);
    System.out.println("*******");

    Decoder decoder = Base64.getMimeDecoder();
    
    byte[] bs_1 = decoder.decode(base64_1);
    System.out.println(new String(bs_1, "utf-8"));
    System.out.println("*******");
    
    byte[] bs_2 = decoder.decode(base64_2);
    System.out.println(new String(bs_2, "utf-8"));
  }
}

打印结果：

6ZSE56a+5pel5b2T5Y2I77yM5rGX5ru056a+5LiL5Zyf44CCCuiwgeefpeebmOS4remkkO+8jOeykueykueahui+m+iLpuOAgg==
*******
6ZSE56a+5pel5b2T5Y2I77yM5rGX5ru056a+5LiL5Zyf44CCCuiwgeefpeebmOS4remkkO+8jOey
kueykueahui+m+iLpuOAgg==
*******
锄禾日当午，汗滴禾下土。
谁知盘中餐，粒粒皆辛苦。
*******
锄禾日当午，汗滴禾下土。
谁知盘中餐，粒粒皆辛苦。