UDFMD5.java

package com.facebook.hive.udf;

import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDF;

import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * Returns the MD5 hash of argument
 */
@Description(name = "udfMD5",
             value = "_FUNC_(string) - MD5",
    extended = "Example:\n"
             + "  > SELECT MD5('hashme') FROM potato;\n")
  public class UDFMD5 extends UDF {
    public String evaluate(String message) {
      try {
        MessageDigest md = MessageDigest.getInstance("MD5");
        md.update(message.getBytes());
        byte[] message_digest = md.digest();
        BigInteger msg_int = new BigInteger(1, message_digest);
        String hash_string = msg_int.toString(16);
        while(hash_string.length() < 32) {
          // pre-pend with zeros if necessary
          hash_string = "0"+hash_string;
        }
        return hash_string;
      } catch (NoSuchAlgorithmException e) {
        // If MD5 is not available
        return null;
      } catch (NullPointerException e) {
        // If input is null
        return null;
      }
    }
  }