SHA256加密算法

非对称算法SHA256，使用场景如密码加密等，现记录如下

package com.example.utils;

import lombok.extern.slf4j.Slf4j;

import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

@Slf4j
public class SHA256Utils {

    /**
     * sha256加密
     *
     * @param str 要加密的字符串
     * @return 加密后的字符串
     */
    public static String getSha256Str(String str) {
        MessageDigest messageDigest;
        String encodeStr = "";
        try {
            messageDigest = MessageDigest.getInstance("SHA-256");
            messageDigest.update(str.getBytes(StandardCharsets.UTF_8));
            encodeStr = byte2Hex(messageDigest.digest());
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return encodeStr;
    }

    /**
     * sha256加密
     *
     * @param str 要加密的字符串
     * @return 加密后的byte数组
     */
    public static byte[] getSha256(String str) {
        MessageDigest messageDigest;
        byte[] encodeStr = null;
        try {
            messageDigest = MessageDigest.getInstance("SHA-256");
            messageDigest.update(str.getBytes(StandardCharsets.UTF_8));
            encodeStr = messageDigest.digest();
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return encodeStr;
    }

    /**
     * sha256加密 将byte转为16进制
     *
     * @param bytes 字节码
     * @return 加密后的字符串
     */
    private static String byte2Hex(byte[] bytes) {
        StringBuilder stringBuilder = new StringBuilder();
        String temp;
        for (byte aByte : bytes) {
            temp = Integer.toHexString(aByte & 0xFF);
            if (temp.length() == 1) {
                //1得到一位的进行补0操作
                stringBuilder.append("0");
            }
            stringBuilder.append(temp);
        }
        return stringBuilder.toString();
    }

    public static void main(String[] args) {
        String encodeStr = getSha256Str("123456");
        // 8d969eef6ecad3c29a3a629280e686cf0c3f5d5a86aff3ca12020c923adc6c92
        System.out.println(encodeStr);
    }
}