base64.java

来自「java mail,java mailjava mailjava mailjav」· Java 代码 · 共 79 行

/****************************************************************
 * Licensed to the Apache Software Foundation (ASF) under one   *
 * or more contributor license agreements.  See the NOTICE file *
 * distributed with this work for additional information        *
 * regarding copyright ownership.  The ASF licenses this file   *
 * to you under the Apache License, Version 2.0 (the            *
 * "License"); you may not use this file except in compliance   *
 * with the License.  You may obtain a copy of the License at   *
 *                                                              *
 *   http://www.apache.org/licenses/LICENSE-2.0                 *
 *                                                              *
 * Unless required by applicable law or agreed to in writing,   *
 * software distributed under the License is distributed on an  *
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY       *
 * KIND, either express or implied.  See the License for the    *
 * specific language governing permissions and limitations      *
 * under the License.                                           *
 ****************************************************************/

package org.apache.james.util;

import javax.mail.internet.MimeUtility;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStreamReader;


/**
 * Simple Base64 string decoding function
 *
 * @version This is $Revision: 494012 $
 */

public class Base64 {

    public static BufferedReader decode(String b64string) throws Exception {
        return new BufferedReader(
                   new InputStreamReader(
                       MimeUtility.decode(
                            new ByteArrayInputStream(
                                b64string.getBytes()), "base64")));
    }

    public static String decodeAsString(String b64string) throws Exception {
        if (b64string == null) {
            return b64string;
        }
        String returnString = decode(b64string).readLine();
        if (returnString == null) {
            return returnString;
        }
        return returnString.trim();
    }

    public static ByteArrayOutputStream encode(String plaintext)
            throws Exception {
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        byte[] in = plaintext.getBytes();
        ByteArrayOutputStream inStream = new ByteArrayOutputStream();
        inStream.write(in, 0, in.length);
        // pad
        if ((in.length % 3 ) == 1){
            inStream.write(0);
            inStream.write(0);
        } else if((in.length % 3 ) == 2){
            inStream.write(0);
        }
        inStream.writeTo( MimeUtility.encode(out, "base64")  );
        return out;
    }

    public static String encodeAsString(String plaintext) throws Exception {
        return  encode(plaintext).toString();
    }


}