Java 枚举类示例

本文主要是介绍Java 枚举类示例，对大家解决编程问题具有一定的参考价值，需要的程序猿们随着小编来一起学习吧！

import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.security.MessageDigest;

public enum Hash {

	MD5("MD5"), SHA1("SHA1"), SHA256("SHA-256"), SHA512("SHA-512");

	private String name;

	Hash(String name) {
		this.name = name;
	}

	public String getName() {
		return name;
	}

	public byte[] checksum(File input) {
		try (InputStream in = new FileInputStream(input)) {
			MessageDigest digest = MessageDigest.getInstance(getName());
			byte[] block = new byte[4096];
			int length;
			while ((length = in.read(block)) > 0) {
				digest.update(block, 0, length);
			}
			return digest.digest();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}

}

import java.io.File;

public class FileChecksumExample {

	public static void main(String[] args) throws Exception {

		File file = new File("f:\\Fedora-KDE-Live-x86_64-34-1.2.iso");

		System.out.println("MD5    : " + toHex(Hash.MD5.checksum(file)));
		System.out.println("SHA1   : " + toHex(Hash.SHA1.checksum(file)));
		System.out.println("SHA256 : " + toHex(Hash.SHA256.checksum(file)));
		System.out.println("SHA512 : " + toHex(Hash.SHA512.checksum(file)));
	}

	private static String toHex(byte[] bytes) {
		StringBuilder result = new StringBuilder();
		for (byte aByte : bytes) {
			result.append(String.format("%02x", aByte));
			// upper case
			// result.append(String.format("%02X", aByte));
		}
		return result.toString();
	}

}

这篇关于Java 枚举类示例的文章就介绍到这儿，希望我们推荐的文章对大家有所帮助，也希望大家多多支持为之网！