In java programming, it is often necessary to convert binary data into text format for transmission, and Base64 encoding is a commonly used conversion method.

Base64 converts three bytes of data into four bytes of text data. The text data consists of 64 characters. It only contains printable characters, so it can be used in emails, HTTP request messages, etc. transmitted in the protocol. Java provides Base64 encoding and decoding APIs, so we can easily convert data.

This article will introduce how to use Base64 to encode and decode data in Java.

1. Use the Base64 method provided by Java8 and above versions

Java8 and above versions provide the Base64 class, and we can directly use the methods it provides for encoding and decoding operations.

1. Base64 encoding

Base64 encoding is the process of converting binary data into text form. Java provides some APIs that can easily implement the Base64 encoding process.

String str = "Java Base64編碼解碼";
byte[] data = str.getBytes("UTF-8");
String result = Base64.getEncoder().encodeToString(data);
System.out.println(result);

The output result is: SmF2YSBCYXNlNjQgY29tbWl0IGplZmFjdGlvbg==

The getBytes() method is used to obtain the byte array corresponding to the string, and the Base64.getEncoder().encodeToString() method is used to implement encoding Operation to convert a byte array into a string in Base64 encoding format.

2. Base64 decoding

corresponds to encoding. Decoding is the process of converting a string in Base64 format into binary data. Similarly, Java provides an API to easily implement the Base64 decoding process.

String text = "SmF2YSBCYXNlNjQgY29tbWl0IGplZmFjdGlvbg==";
byte[] data = Base64.getDecoder().decode(text);
String result = new String(data, "UTF-8");
System.out.println(result);

The output result is: Java Base64 encoding and decoding

Among them, the Base64.getDecoder().decode() method can decode the Base64 format string into a byte array, new String() Method converts a byte array to a string.

2. Use Apache Commons Codec to implement Base64 encoding and decoding

The Apache Commons Codec library is an open source project under Apache. It provides some encoding/decoding APIs. In addition to Base64, it also includes Hex, URL, Soundex and other encoding methods. Here, we only introduce how to use the Commons Codec library for Base64 encoding and decoding.

1. Base64 encoding

String str = "Java Base64編碼解碼";
byte[] data = str.getBytes("UTF-8");
String result = org.apache.commons.codec.binary.Base64.encodeBase64String(data);
System.out.println(result);

The output result is the same as above.

Here, we call the encodeBase64String() method in the org.apache.commons.codec.binary.Base64 class to implement Base64 encoding. This method will convert the byte array into a string in Base64 format.

2. Base64 decoding

String text = "SmF2YSBCYXNlNjQgY29tbWl0IGplZmFjdGlvbg==";
byte[] data = org.apache.commons.codec.binary.Base64.decodeBase64(text);
String result = new String(data, "UTF-8");
System.out.println(result);

The output result is the same as above.

Here, we call the decodeBase64() method in the org.apache.commons.codec.binary.Base64 class to implement Base64 decoding. The decodeBase64() method converts a Base64-formatted string into a byte array.

Summary:

Whether you use the Base64 class provided by Java8 or the Apache Commons Codec library, you can easily perform Base64 encoding and decoding. Which method to use depends on the specific situation. In actual programming, we need to choose which method to use according to our needs.

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