Analysis of the technical principles of the Base64 framework in the Java class library
Analysis of the technical principles of the Base64 framework in the Java class library
Base64 is a coding method for encoding binary data as ASCII characters.In the Java library, this encoding method is encapsulated in the Base64 framework, providing a convenient method for Base64 encoding and decoding operations.This article will analyze the technical principles of the Base64 framework in the Java class library, and provide relevant Java code examples.
1. Base64 encoding principle
The base64 encoding transforms binary data to ASCII characters in accordance with certain rules.The main principle is as follows:
-Dilation of binary data to be encoded into 6 -bit fragments.
-The each fragment convert to a decimal value.
-Cer the decimal value to the index in the Base64 character table to get the corresponding character.
-Che all conversion characters to form a string after 64 encoded.
2. Base64 character table
The character table used in the Base64 framework in the Java class library contains 64 characters, as shown below:
ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/
Among them, '=' is a filling character used for alignment.
3. Base64 framework in the Java class library
The Base64 framework in the Java class library provides Java.util.Base64 to perform Base64 encoding and decoding operations.This class contains the following core methods:
- `public static String encodeToString(byte[] src)`
- `public static byte[] encode(byte[] src)`
This method accepts a byte array as a parameter and returns the Base64 -encoded byte array.
- `public static byte[] decode(String src)`
This method accepts a base64 -encoded string as a parameter, and returns the decoding byte array.
- `public static byte[] decode(byte[] src)`
This method accepts a Base64 -encoded byte array as a parameter and returns the decoding byte array.
4. Java code example
The following is an example code that uses the Base64 framework in the Java class library to use the base64 encoding and decoding:
import java.util.Base64;
public class Base64Example {
public static void main(String[] args) {
String originalData = "Hello, World!";
byte[] encodedBytes = Base64.getEncoder().encode(originalData.getBytes());
System.out.println("Base64 encoded string: " + new String(encodedBytes));
byte[] decodedBytes = Base64.getDecoder().decode(encodedBytes);
String decodedData = new String(decodedBytes);
System.out.println("Base64 decoded string: " + decodedData);
}
}
Run the above code, the output result is as follows:
Base64 encoded string: SGVsbG8sIFdvcmxkIQ==
Base64 decoded string: Hello, World!
In the above code, first convert the original data "hello, world!" To byte array, then use the base64 encoding method for coding, and convert the encoded byte array into strings for output.Then, use the base64 decoding method to decode the encoded string to be decoded into byte array, and convert the decoding byte array to a string to output.
In summary, the Base64 framework in the Java class library has achieved the function of converting binary data into ASCII characters and restoring raw data from Base64 by coding and decoding the binary data.By using the method provided by the Base64 category, we can easily perform the Base64 encoding and decoding operation.
