com.xiangzhurui.util.email.POP3Mail.java Source code

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Here is the source code for com.xiangzhurui.util.email.POP3Mail.java

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/*
 * 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 com.xiangzhurui.util.email;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Locale;

import org.apache.commons.net.PrintCommandListener;
import org.apache.commons.net.pop3.POP3Client;
import org.apache.commons.net.pop3.POP3MessageInfo;
import org.apache.commons.net.pop3.POP3SClient;

/**
 * This is an example program demonstrating how to use the POP3[S]Client class.
 * This program connects to a POP3[S] server and retrieves the message headers
 * of all the messages, printing the From: and Subject: header entries for each
 * message.
 * <p>
 * Usage: POP3Mail <pop3[s] server hostname> <username> <password> [secure
 * protocol, e.g. TLS]
 */
public final class POP3Mail {

    public static final void printMessageInfo(BufferedReader reader, int id) throws IOException {
        String from = "";
        String subject = "";
        String line;
        while ((line = reader.readLine()) != null) {
            String lower = line.toLowerCase(Locale.ENGLISH);
            if (lower.startsWith("from: ")) {
                from = line.substring(6).trim();
            } else if (lower.startsWith("subject: ")) {
                subject = line.substring(9).trim();
            }
        }

        System.out.println(id + " From: " + from + "  Subject: " + subject);
    }

    public static void main(String[] args) {
        if (args.length < 3) {
            System.err
                    .println("Usage: POP3Mail <pop3 server hostname> <username> <password> [TLS [true=implicit]]");
            System.exit(1);
        }

        String server = args[0];
        String username = args[1];
        String password = args[2];

        String proto = args.length > 3 ? args[3] : null;
        boolean implicit = args.length > 4 && Boolean.parseBoolean(args[4]);

        POP3Client pop3;

        if (proto != null) {
            System.out.println("Using secure protocol: " + proto);
            pop3 = new POP3SClient(proto, implicit);
        } else {
            pop3 = new POP3Client();
        }
        System.out.println("Connecting to server " + server + " on " + pop3.getDefaultPort());

        // We want to timeout if a response takes longer than 60 seconds
        pop3.setDefaultTimeout(60000);

        // suppress login details
        pop3.addProtocolCommandListener(new PrintCommandListener(new PrintWriter(System.out), true));

        try {
            pop3.connect(server);
        } catch (IOException e) {
            System.err.println("Could not connect to server.");
            e.printStackTrace();
            System.exit(1);
        }

        try {
            if (!pop3.login(username, password)) {
                System.err.println("Could not login to server.  Check password.");
                pop3.disconnect();
                System.exit(1);
            }

            POP3MessageInfo[] messages = pop3.listMessages();

            if (messages == null) {
                System.err.println("Could not retrieve message list.");
                pop3.disconnect();
                return;
            } else if (messages.length == 0) {
                System.out.println("No messages");
                pop3.logout();
                pop3.disconnect();
                return;
            }

            for (POP3MessageInfo msginfo : messages) {
                BufferedReader reader = (BufferedReader) pop3.retrieveMessageTop(msginfo.number, 0);

                if (reader == null) {
                    System.err.println("Could not retrieve message header.");
                    pop3.disconnect();
                    System.exit(1);
                }
                printMessageInfo(reader, msginfo.number);
            }

            pop3.logout();
            pop3.disconnect();
        } catch (IOException e) {
            e.printStackTrace();
            return;
        }
    }
}