我正在尝试使用Java程序读取未读的电子邮件。我正在使用下面提到的来自https://www.tutorialspoint.com/javamail_api/javamail_api_fetching_emails.htm的Java代码。我在gmail设置中打开了不安全的应用访问权限。请帮助我解决问题。
public class FetchingEmail {
public static void fetch(String pop3Host, String storeType, String user,
String password) {
try {
Properties properties = new Properties();
properties.put("mail.store.protocol", "pop3");
properties.put("mail.pop3.host", pop3Host);
properties.put("mail.pop3.port", "995");
properties.put("mail.pop3.starttls.enable", "*");
Session emailSession = Session.getDefaultInstance(properties);
Store store = emailSession.getStore("pop3s");
store.connect(pop3Host, user, password);
Folder emailFolder = store.getFolder("INBOX");
emailFolder.open(Folder.READ_ONLY);
BufferedReader reader = new BufferedReader(new InputStreamReader(
System.in));
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("---------------------------------");
writePart(message);
String line = reader.readLine();
if ("YES".equals(line)) {
message.writeTo(System.out);
} else if ("QUIT".equals(line)) {
break;
}
}
emailFolder.close(false);
store.close();
} catch (NoSuchProviderException e) {
e.printStackTrace();
} catch (MessagingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
String host = "pop.gmail.com";// change accordingly
String mailStoreType = "pop3";
String username = "abc@gmail.com";
//"abc@gmail.com";// change accordingly
String password = "abc";// change accordingly
fetch(host, mailStoreType, username, password);
}
public static void writePart(Part p) throws Exception {
if (p instanceof Message)
writeEnvelope((Message) p);
System.out.println("----------------------------");
System.out.println("CONTENT-TYPE: " + p.getContentType());
if (p.isMimeType("text/plain")) {
System.out.println("This is plain text");
System.out.println("---------------------------");
System.out.println((String) p.getContent());
}
else if (p.isMimeType("multipart/*")) {
System.out.println("This is a Multipart");
System.out.println("---------------------------");
Multipart mp = (Multipart) p.getContent();
int count = mp.getCount();
for (int i = 0; i < count; i++)
writePart(mp.getBodyPart(i));
}
else if (p.isMimeType("message/rfc822")) {
System.out.println("This is a Nested Message");
System.out.println("---------------------------");
writePart((Part) p.getContent());
}
else if (p.getContentType().contains("image/")) {
System.out.println("content type" + p.getContentType());
File f = new File("image" + new Date().getTime() + ".jpg");
DataOutputStream output = new DataOutputStream(
new BufferedOutputStream(new FileOutputStream(f)));
com.sun.mail.util.BASE64DecoderStream test =
(com.sun.mail.util.BASE64DecoderStream) p
.getContent();
byte[] buffer = new byte[1024];
int bytesRead;
while ((bytesRead = test.read(buffer)) != -1) {
output.write(buffer, 0, bytesRead);
}
}
else {
Object o = p.getContent();
if (o instanceof String) {
System.out.println("This is a string");
System.out.println("---------------------------");
System.out.println((String) o);
}
else if (o instanceof InputStream) {
System.out.println("This is just an input stream");
System.out.println("---------------------------");
InputStream is = (InputStream) o;
is = (InputStream) o;
int c;
while ((c = is.read()) != -1)
System.out.write(c);
}
else {
System.out.println("This is an unknown type");
System.out.println("---------------------------");
System.out.println(o.toString());
}
}
}
public static void writeEnvelope(Message m) throws Exception {
System.out.println("This is the message envelope");
System.out.println("---------------------------");
Address[] a;
if ((a = m.getFrom()) != null) {
for (int j = 0; j < a.length; j++)
System.out.println("FROM: " + a[j].toString());
}
if ((a = m.getRecipients(Message.RecipientType.TO)) != null) {
for (int j = 0; j < a.length; j++)
System.out.println("TO: " + a[j].toString());
}
if (m.getSubject() != null)
System.out.println("SUBJECT: " + m.getSubject());
}
}
但是我正在获得例外。我已经发布了堆栈跟踪。
javax.mail.MessagingException: Connect failed;
nested exception is:
javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at com.sun.mail.pop3.POP3Store.protocolConnect(POP3Store.java:213)
at javax.mail.Service.connect(Service.java:366)
at javax.mail.Service.connect(Service.java:246)
at com.util.FetchingEmail.fetch(FetchingEmail.java:62)
at com.util.FetchingEmail.main(FetchingEmail.java:110)
Caused by: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at sun.security.ssl.Alerts.getSSLException(Alerts.java:192)
at sun.security.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1964)
at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:328)
at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:322)
at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1614)
at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:216)
at sun.security.ssl.Handshaker.processLoop(Handshaker.java:1052)
at sun.security.ssl.Handshaker.process_record(Handshaker.java:987)
at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1072)
at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1385)
at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1413)
at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1397)
at com.sun.mail.util.SocketFetcher.configureSSLSocket(SocketFetcher.java:598)
at com.sun.mail.util.SocketFetcher.createSocket(SocketFetcher.java:372)
at com.sun.mail.util.SocketFetcher.getSocket(SocketFetcher.java:238)
at com.sun.mail.pop3.Protocol.<init>(Protocol.java:112)
at com.sun.mail.pop3.POP3Store.getPort(POP3Store.java:265)
at com.sun.mail.pop3.POP3Store.protocolConnect(POP3Store.java:207)
... 4 more
Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:397)
at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:302)
at sun.security.validator.Validator.validate(Validator.java:260)
at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:324)
at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:229)
at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:124)
at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1596)
... 17 more
Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at sun.security.provider.certpath.SunCertPathBuilder.build(SunCertPathBuilder.java:141)
at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(SunCertPathBuilder.java:126)
at java.security.cert.CertPathBuilder.build(CertPathBuilder.java:280)
at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:392)