在本章中，我们将了解如何使用JavaMail API删除电子邮件.删除消息涉及使用与消息关联的标志.不同的状态有不同的标志，一些是系统定义的，一些是用户定义的.预定义标志在内部类Flags.Flag中定义，如下所示:
Flags.Flag.ANSWERED
Flags.Flag.DELETED
Flags.Flag.DRAFT
Flags.Flag.FLAGGED
Flags.Flag.RECENT
Flags.Flag.SEEN
Flags.Flag.USER
POP协议仅支持删除邮件.
删除程序中遵循的基本步骤为:
在属性中获取具有POP和SMPT服务器详细信息的Session对象.我们需要POP详细信息来检索消息和SMPT详细信息以发送消息.
创建POP3商店对象并连接到商店.
创建文件夹对象并以READ_WRITE模式打开邮箱中的相应文件夹.
从收件箱文件夹中检索邮件.
如果要通过调用setFlag方法删除消息(Flags.Flag.DELETED，则迭代消息并输入"Y"或"y".在Message对象上.
标记为DELETED的消息实际上没有删除，直到我们调用Folder对象上的expunge()方法，或关闭将expunge设置为true的文件夹.
关闭商店对象.
创建一个java类文件 ForwardEmail ，其内容如下:
package com.it1352;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Properties;
import javax.mail.Flags;
import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.NoSuchProviderException;
import javax.mail.Session;
import javax.mail.Store;
public class DeleteEmail {
public static void delete(String pop3Host, String storeType, String user,
String password)
{
try
{
// get the session object
Properties properties = new Properties();
properties.put("mail.store.protocol", "pop3");
properties.put("mail.pop3s.host", pop3Host);
properties.put("mail.pop3s.port", "995");
properties.put("mail.pop3.starttls.enable", "true");
Session emailSession = Session.getDefaultInstance(properties);
// emailSession.setDebug(true);
// create the POP3 store object and connect with the pop server
Store store = emailSession.getStore("pop3s");
store.connect(pop3Host, user, password);
// create the folder object and open it
Folder emailFolder = store.getFolder("INBOX");
emailFolder.open(Folder.READ_WRITE);
BufferedReader reader = new BufferedReader(new InputStreamReader(
System.in));
// retrieve the messages from the folder in an array and print it
Message[] messages = emailFolder.getMessages();
System.out.println("messages.length---" + messages.length);
for (int i = 0; i < messages.length; i++) {
Message message = messages[i];
System.out.println("---------------------------------");
System.out.println("Email Number " + (i + 1));
System.out.println("Subject: " + message.getSubject());
System.out.println("From: " + message.getFrom()[0]);
String subject = message.getSubject();
System.out.print("Do you want to delete this message [y/n] ? ");
String ans = reader.readLine();
if ("Y".equals(ans) || "y".equals(ans)) {
// set the DELETE flag to true
message.setFlag(Flags.Flag.DELETED, true);
System.out.println("Marked DELETE for message: " + subject);
} else if ("n".equals(ans)) {
break;
}
}
// expunges the folder to remove messages which are marked deleted
emailFolder.close(true);
store.close();
} catch (NoSuchProviderException e) {
e.printStackTrace();
} catch (MessagingException e) {
e.printStackTrace();
} catch (IOException io) {
io.printStackTrace();
}
}
public static void main(String[] args) {
String host = "pop.gmail.com";// change accordingly
String mailStoreType = "pop3";
String username = "abc@gmail.com";// change accordingly
String password = "*****";// change accordingly
delete(host, mailStoreType, username, password);
}
}您可以通过取消注释语句 emailSession来设置调试开启.setDebug(true);
现在我们的类已准备就绪，让我们编译上面的类.我已将类DeleteEmail.java保存到目录:/home/manisha/JavaMailAPIExercise .我们需要类路径中的jar javax.mail.jar 和 activation.jar .执行以下命令从命令提示符编译类(两个jar放在/home/manisha/目录中):
javac -cp/home/manisha/activation.jar:/home/manisha/javax.mail.jar:DeleEmail.java
现在该类已编译，请执行以下命令运行:
java -cp/home/manisha/activation.jar:/home/manisha/javax.mail.jar:DeleEmail
您应该在命令控制台上看到以下消息:
messages.length---1 --------------------------------- Email Number 1 Subject: Testing From: ABC <abc@gmail.com> Do you want to delete this message [y/n] ? y Marked DELETE for message: Testing
