生成随机字符串
public static String getRandomString(int length) { //length表示生成字符串的长度
String base = "abcdefghijklmnopqrstuvwxyz0123456789";
Random random = new Random();
StringBuffer sb = new StringBuffer();
for (int i = 0; i < length; i++) {
int number = random.nextInt(base.length());
sb.append(base.charAt(number));
}
return sb.toString();
}
Md5加密
public static String md5(String string) {
byte[] hash;
try {
//获取指定加密字符串的摘要
hash = MessageDigest.getInstance("MD5").digest(string.getBytes("UTF-8"));
} catch (NoSuchAlgorithmException e) {
throw new RuntimeException("Huh, MD5 should be supported?", e);
} catch (UnsupportedEncodingException e) {
throw new RuntimeException("Huh, UTF-8 should be supported?", e);
}
StringBuilder hex = new StringBuilder(hash.length * 2);
for (byte b : hash) {
if ((b & 0xFF) < 0x10) hex.append("0");
//通过b & 0xFF运算获得int值，再通过Integer.toHexString转成16进制字符串。
hex.append(Integer.toHexString(b & 0xFF));
}
return hex.toString();
}
