javamail邮件发送

按这条博客写的方法https://www.cnblogs.com/xdp-gacl/p/4216311.html

日志信息：

DEBUG SMTP: AUTH LOGIN command trace suppressed
DEBUG SMTP: AUTH LOGIN succeeded
DEBUG: getProvider() returning javax.mail.Provider[TRANSPORT,smtp,com.sun.mail.smtp.SMTPTransport,Oracle]
DEBUG SMTP: need username and password for authentication
DEBUG SMTP: protocolConnect returning false, host=smtp.sina.com, user=fyf, password=<null>
javax.mail.AuthenticationFailedException: failed to connect, no password specified?

显示登录成功但是发送需要认证（need username and password for authentication）

所以session获取方法需要修改，添加认证信息

Session session = Session.getInstance(prop);

 改为

Session session = Session.getDefaultInstance(prop,new SimpleAuthenticator(USERNAME,PASSWORD));

其中SimpleAuthenticator类需要继承javax.mail.Authenticator;

因为javax.mail.Authenticator;并没有实现getPasswordAuthentication()方法，根据Authenticator中对该方法的描述

    /**
     * Called when password authentication is needed.  Subclasses should
     * override the default implementation, which returns null. <p>
     *
     * Note that if this method uses a dialog to prompt the user for this
     * information, the dialog needs to block until the user supplies the
     * information.  This method can not simply return after showing the
     * dialog.
     * @return The PasswordAuthentication collected from the
     *		user, or null if none is provided.
     */
    protected PasswordAuthentication getPasswordAuthentication() {
	return null;
    }

 当需要密码认证是会被调用，子类必须实现该方法，并返回PasswordAuthentication，重写代码如下

代码如下

package com.taotao.common.utils;

import javax.mail.Authenticator;
import javax.mail.PasswordAuthentication;

public class SimpleAuthenticator extends Authenticator {
    
    private String username;
    private String password;
    
    public SimpleAuthenticator(String username, String password) {
        super();
        this.username = username;
        this.password = password;
    }

    @Override
    protected PasswordAuthentication getPasswordAuthentication() {
        // TODO Auto-generated method stub
        return new PasswordAuthentication(username, password);
    }
    
}

 再次运行发送成功

DEBUG SMTP: Attempt to authenticate using mechanisms: LOGIN PLAIN DIGEST-MD5 NTLM XOAUTH2 
DEBUG SMTP: Using mechanism LOGIN
DEBUG SMTP: AUTH LOGIN command trace suppressed
DEBUG SMTP: AUTH LOGIN succeeded
DEBUG SMTP: use8bit false
MAIL FROM:<yonglai_zhuce@sina.com>
250 ok
RCPT TO:<truthmustdie@163.com>
250 ok
DEBUG SMTP: Verified Addresses
DEBUG SMTP:   truthmustdie@163.com
DATA
354 End data with <CR><LF>.<CR><LF>
Date: Fri, 14 Dec 2018 20:26:37 +0800 (CST)
From: yonglai_zhuce@sina.com
To: truthmustdie@163.com