import java.io.UnsupportedEncodingException; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; public class TestMain { public String md5(String plainText) throws NoSuchAlgorithmException, UnsupportedEncodingException { // a b c d e f 也可以改成大写的 A B C D E F char[] feedArray = new char[]{'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'}; MessageDigest msgDigest = MessageDigest.getInstance("MD5"); msgDigest.update(plainText.getBytes("UTF-8")); byte[] bytes = msgDigest.digest(); int length = bytes.length; char[] out = new char[length << 1]; for (int i = 0, j = 0; i < length; i++) { out[j++] = feedArray[(0xF0 & bytes[i]) >>> 4]; out[j++] = feedArray[0xF0 & bytes[i]]; } String md5Str = new String(out); return md5Str; } }
第二种实现
import java.io.UnsupportedEncodingException; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; public class TestMain { public String md5(String plainText) throws NoSuchAlgorithmException, UnsupportedEncodingException { // a b c d e f 也可以改成大写的 A B C D E F char[] feedArray = new char[]{'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'}; MessageDigest msgDigest = MessageDigest.getInstance("MD5"); msgDigest.update(plainText.getBytes("UTF-8")); byte[] bytes = msgDigest.digest(); char[] out = new char[16 * 2]; for (int i = 0, j = 0; i < 16; i++) { out[j++] = feedArray[bytes[i] >>> 4 & 0xf]; out[j++] = feedArray[bytes[i] & 0xf]; } String md5Str = new String(out); return md5Str; } }
其中plainText 参数就是你传入的明文信息 经过md5加密以后会变成32位长度的字符串