com.sun.mail.smtp.SMTPSendFailedException: 503 Error: need EHLO and AUTH first !

Properties props = System.getProperties();

props.setProperty("mail.smtp.host", "smtp.qq.com");

props.setProperty("mail.smtp.port", "25");

props.put("mail.smtp.auth", "true");  //如果这行不写或写成props.put("mail.smtp.auth", true);将会报如上异常，注意：true是字符串格式的参数。