Spring Boot教程（十）：登录密码数据加密

MessageDigest 类为应用程序提供信息摘要算法的功能，如 MD5 或 SHA 算法。信息摘要是安全的单向哈希函数，它接收任意大小的数据，输出固定长度的哈希值。

下面通过代码来演示一下具体的用法：

import java.security.MessageDigest;

public class Demo {
    
    
    private static final String hexDigits[] = {
    
    "0", "1", "2", "3", "4", "5",
            "6", "7", "8", "9", "a", "b", "c", "d", "e", "f"};

    private static String byteArrayToHexString(byte b[]) {
    
    
        StringBuffer resultSb = new StringBuffer();
        for (int i = 0; i < b.length; i++)
            resultSb.append(byteToHexString(b[i]));

        return resultSb.toString();
    }

    private static String byteToHexString(byte b) {
    
    
        int n = b;
        if (n < 0)
            n += 256;
        int d1 = n / 16;
        int d2 = n % 16;
        return hexDigits[d1] + hexDigits[d2];
    }

    public static String MD5Encode(String origin, String charsetname) {
    
    
        String resultString = null;
        try {
    
    
            resultString = origin;
            MessageDigest md = MessageDigest.getInstance("MD5");
            if (charsetname == null || "".equals(charsetname))
                resultString = byteArrayToHexString(md.digest(resultString
                        .getBytes()));
            else
                resultString = byteArrayToHexString(md.digest(resultString
                        .getBytes(charsetname)));
        } catch (Exception exception) {
    
    
        }
        return resultString;
    }

    //就地测试一下
    public static void main(String[] args) {
    
    
        String pass="tuantuan";
        String passMD5=Demo.MD5Encode(pass,"UTF-8");
        System.out.println("pass:"+pass);
        System.out.println("passMD5:"+passMD5);
    }
}

运行main方法后，得到加密前和加密后的pass：