版权声明:feixie https://blog.csdn.net/qq_36850813/article/details/85014749
package com.test.general.md5;
import java.math.BigInteger;
import java.security.MessageDigest;
public class app1 {
public static void main(String[] args) {
String md5 = getMD5("1");
String md52 = MD5("1");
System.out.println(md5);
System.out.println(md52);
}
/* 对字符串md5加密(小写+字母)
*
* @return
*/
public static String getMD5(String str) {
try {
// 生成一个MD5加密计算摘要
MessageDigest md = MessageDigest.getInstance("MD5");
// 计算md5函数
md.update(str.getBytes());
// digest()最后确定返回md5 hash值,返回值为8为字符串。因为md5 hash值是16位的hex值,实际上就是8位的字符
// BigInteger函数则将8位的字符串转换成16位hex值,用字符串来表示;得到字符串形式的hash值
return new BigInteger(1,md.digest()).toString(16);
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
/* 对字符串md5加密(大写+数字)
*
* @param str
* @return
*/
public static String MD5(String str) {
char hexDigits[]={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};
try {
byte[] btInput = str.getBytes();
// 获得MD5摘要算法的 MessageDigest 对象
MessageDigest mdInst = MessageDigest.getInstance("MD5");
// 使用指定的字节更新摘要
mdInst.update(btInput);
// 获得密文
byte[] md = mdInst.digest();
// 把密文转换成十六进制的字符串形式
char s[] = new char[md.length * 2];
int k=0;
for (int i = 0; i <md.length ; i++) {
byte byte0 = md[i];
s[k++]=hexDigits[byte0 >>>4 & 0xf];
s[k++]=hexDigits[byte0 & 0xf];
}
return new String(s);
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
private final static String[] hexDigits = {"0", "1", "2", "3", "4", "5", "6", "7",
"8", "9", "a", "b", "c", "d", "e", "f"};
/*
* 转换字节数组为16进制字串
*/
public static String byteArrayToHexString(byte[] b) {
StringBuilder resultSb = new StringBuilder();
for (byte aB : b) {
resultSb.append(byteToHexString(aB));
}
return resultSb.toString();
}
/*
* 转换byte到16进制
*/
private static String byteToHexString(byte b) {
int n = b;
if (n < 0) {
n = 256 + n;
}
int d1 = n / 16;
int d2 = n % 16;
return hexDigits[d1] + hexDigits[d2];
}
}