Java Key Public getPublicKey(String publicKeyFilepath, String algorithm)

Description

Creates a PublicKey from the specified public key file and algorithm.

License

Open Source License

Parameter

Parameter	Description
publicKeyFilepath	location of public key file
algorithm	algorithm of specified key file

Exception

Parameter	Description
IOException	an exception
NoSuchAlgorithmException	an exception
InvalidKeySpecException	an exception

Return

PublicKey object representing contents of specified public key file, null if error in generating key or invalid file specified

Declaration

public static PublicKey getPublicKey(String publicKeyFilepath, String algorithm)
        throws IOException, NoSuchAlgorithmException, InvalidKeySpecException

Method Source Code

//package com.java2s;

import java.io.FileInputStream;

import java.io.IOException;
import java.io.InputStream;

import java.net.MalformedURLException;
import java.net.URL;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;

import java.security.PublicKey;
import java.security.spec.InvalidKeySpecException;

import java.security.spec.X509EncodedKeySpec;

public class Main {
    /**//from  w  ww .  jav  a 2  s .c  o m
     * Creates a PublicKey from the specified public key file and algorithm.
     * Returns null if failure to generate PublicKey.
     * 
     * @param publicKeyFilepath location of public key file
     * @param algorithm algorithm of specified key file
     * @return PublicKey object representing contents of specified public key
     *         file, null if error in generating key or invalid file specified
    * @throws IOException 
    * @throws NoSuchAlgorithmException 
    * @throws InvalidKeySpecException 
     */
    public static PublicKey getPublicKey(String publicKeyFilepath, String algorithm)
            throws IOException, NoSuchAlgorithmException, InvalidKeySpecException {
        InputStream pubKey = null;
        try {
            URL url = new URL(publicKeyFilepath);
            pubKey = url.openStream();
        } catch (MalformedURLException e) {
            pubKey = new FileInputStream(publicKeyFilepath);
        }
        byte[] bytes = new byte[pubKey.available()];
        pubKey.read(bytes);
        pubKey.close();
        X509EncodedKeySpec pubSpec = new X509EncodedKeySpec(bytes);
        KeyFactory factory = KeyFactory.getInstance(algorithm);
        return factory.generatePublic(pubSpec);
    }
}