Explore the technical principles of the Base64 framework in the Java class library

Base64 is a 64 -printed character -based encoding scheme that can convert binary data into readable text formats.In the Java library, the Base64 framework provides support for Base64 encoding and decoding.This article will explore the technical principles of the Base64 framework in the Java library and provide the corresponding Java code example. 1. Base64 encoding principle Base64 encoding is a process of transforming binary data into text format.It encodes the binary data of every 3 bytes into 4 printed Base64 characters.The encoding process is as follows: 1. Divide the input data from 3 bytes. 3. Convert the 6 of each group to the corresponding base64 character. The base64 encoding uses a character table containing 64 characters, usually containing lowercase letters, numbers, and two special characters (such as '+' and '/').Each character's coding value in the ASCII table is 0 to 63, corresponding to the position on the character table. The Base64 framework in the Java class library uses a standard Base64 encoding solution, namely the BASE64 encoding scheme specified in the RFC 4648.This standard specifies the arrangement of the Base64 character table and defines the details of the base64 encoding. 2. Base64 decoding principle The Base64 decoding is to convert the base64 -encoded text format into primitive binary data.The decoding process is opposite to the encoding process. The specific steps are as follows: 1. Divide the input data from 4 characters. 2. Convert the position of each character in the Base64 character to a 6 -bit bit bit sequence. 3. Combine the four 6 -bit of each group into a 24 -bit byte. 4. For each byte, 8 -bit height as part of the decoding result. Base64 decoding will ignore the filling characters in the Base64 character table (usually '='), and return the decoding result as the byte array. 3. Java code example The Java class library provides Java.util.base64, which encapsulates the Base64 encoding and decoding method.The following is an example code for base64 encoding and decoding: 1. Base64 encoding example: import java.util.Base64; public class Base64Example { public static void main(String[] args) { // Binary data to be coded byte[] binaryData = { 0x41, 0x42, 0x43 }; // Use base64 encoding byte[] encodedData = Base64.getEncoder().encode(binaryData); String encodedString = new String(encodedData); System.out.println ("base64 encoding result:"); System.out.println(encodedString); } } 2. Base64 decoding example: import java.util.Base64; public class Base64Example { public static void main(String[] args) { // Base64 text to be decoded String encodedString = "QUJD"; // Use Base64 decoding byte[] decodedData = Base64.getDecoder().decode(encodedString); String decodedString = new String(decodedData); System.out.println ("Base64 decoding result:"); System.out.println(decodedString); } } The above two examples demonstrate the process of Base64 encoding and decoding respectively. The Base64 framework in the Java class library can easily perform Base64 encoding and decoding operations.