如何在Java中将字节数组转换为Base64？

Question

好的,我知道如何在C#中做到这一点.

它很简单:

Convert.ToBase64String(byte[])
and Convert.FromBase64String(string) to get byte[] back.

我怎么能用Java做到这一点？

Answer 1

Java 8+

编码或解码字节数组:

byte[] encoded = Base64.getEncoder().encode("Hello".getBytes());
println(new String(encoded));   // Outputs "SGVsbG8="

byte[] decoded = Base64.getDecoder().decode(encoded);
println(new String(decoded))    // Outputs "Hello"

或者如果你只是想要字符串:

String encoded = Base64.getEncoder().encodeToString("Hello".getBytes());
println(encoded);   // Outputs "SGVsbG8="

String decoded = new String(Base64.getDecoder().decode(encoded.getBytes()));
println(decoded)    // Outputs "Hello"

有关详细信息,请参阅Base64.

Java <8

Base64不与小于8的Java版本捆绑在一起.我建议使用Apache Commons Codec.

对于直接字节数组:

Base64 codec = new Base64();
byte[] encoded = codec.encode("Hello".getBytes());
println(new String(encoded));   // Outputs "SGVsbG8="

byte[] decoded = codec.decode(encoded);
println(new String(decoded))    // Outputs "Hello"

或者如果你只是想要字符串:

Base64 codec = new Base64();
String encoded = codec.encodeBase64String("Hello".getBytes());
println(encoded);   // Outputs "SGVsbG8="

String decoded = new String(codec.decodeBase64(encoded));
println(decoded)    // Outputs "Hello"

Android(Java <8)

如果您在Java 8之前使用Android SDK,那么您最好的选择是使用捆绑的android.util.Base64.

对于直接字节数组:

byte[] encoded = Base64.encode("Hello".getBytes());
println(new String(encoded))    // Outputs "SGVsbG8="

byte [] decoded = Base64.decode(encoded);
println(new String(decoded))    // Outputs "Hello"

或者如果你只是想要字符串:

String encoded = Base64.encodeToString("Hello".getBytes());
println(encoded);   // Outputs "SGVsbG8="

String decoded = new String(Base64.decode(encoded));
println(decoded)    // Outputs "Hello"

Answer 2

使用:

byte[] data = Base64.encode(base64str);

编码转换为Base64

您需要从项目中引用commons编解码器才能使该代码生效.

对于java8:

import java.util.Base64

Answer 3

此外，对于我们的Android朋友（API级别8）：

import android.util.Base64

...

Base64.encodeToString(bytes, Base64.DEFAULT);

Answer 4

In case you happen to be using Spring framework along with java, there is an easy way around.

1. Import the following.

   import org.springframework.util.Base64Utils;

2. Convert like this.

   byte[] bytearr ={0,1,2,3,4};
   String encodedText = Base64Utils.encodeToString(bytearr);
   

   To decode you can use the decodeToString method of the Base64Utils class.