java中MD5函数

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class MD5Utils {
//静态方法，便于作为工具类
public static String getMD5(String plainText) {
try {
MessageDigest md = MessageDigest.getInstance("MD5");
md.update(plainText.getBytes());
byte b[] = md.digest();

int i;

StringBuffer buf = new StringBuffer("");
for (int offset = 0; offset < b.length; offset++) {
i = b[offset];
if (i < 0)
i += 256;
if (i < 16)
buf.append("0");
buf.append(Integer.toHexString(i));
}
//32位加密
return buf.toString();
// 16位的加密
//return buf.toString().substring(8, 24);
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
return null;
}

}

public static void main(String[] args) {
//测试
System.out.println(MD5Utils.getMD5("hello"));
}
}