如何避免Java中的代码重复

时间：2018-08-28 12:31:58

标签： java javamail 

public static void sendMail(String[] to, String subject, String messageBody, String[] cc, String[] bcc) throws Exception {
    Properties props = System.getProperties();
    props.put("mail.transport.protocol", "smtp");
    props.put("mail.smtp.port", PORT);
    props.put("mail.smtp.starttls.enable", "true");
    props.put("mail.smtp.auth", "true");
    Session session = Session.getDefaultInstance(props);
    MimeMessage msg = new MimeMessage(session);
    msg.setFrom(new InternetAddress(from, fromname));
    InternetAddress[] toAddress = new InternetAddress[to.length];
    for (int i = 0; i < to.length; i++) {
        toAddress[i] = new InternetAddress(to[i]);    
    }
    for (int i = 0; i < toAddress.length; i++) {
        msg.addRecipient(Message.RecipientType.TO, toAddress[i]);
    }
    msg.setSubject(subject);
    msg.setContent(messageBody, "text/html");
    if(cc[0] != "") {
        InternetAddress[] ccAddress = new InternetAddress[cc.length];
        for (int i = 0; i < cc.length; i++) {
            ccAddress[i] = new InternetAddress(cc[i]);
        }
        for (int i = 0; i < ccAddress.length; i++) {
            msg.addRecipient(Message.RecipientType.CC, ccAddress[i]);
        }
    }
    if(bcc[0] != "") {
        InternetAddress[] bccAddress = new InternetAddress[bcc.length];
        for (int i = 0; i < bcc.length; i++) {
            bccAddress[i] = new InternetAddress(bcc[i]);
        }
        for (int i = 0; i < bccAddress.length; i++) {
            msg.addRecipient(Message.RecipientType.BCC, bccAddress[i]);
        }
    }
    Transport transport = session.getTransport();
    try {
        System.out.println("Sending...");
        transport.connect(HOST, SMTP_USERNAME, SMTP_PASSWORD);
        transport.sendMessage(msg, msg.getAllRecipients());
        System.out.println("Email sent!");
    } catch (Exception ex) {
        System.out.println("The email was not sent.");
        System.out.println("Error message: " + ex.getMessage());
    } finally {
        transport.close();
    }
}
public static void sendMail(String[] to, String subject, String messageBody) throws Exception {
    Properties props = System.getProperties();
    props.put("mail.transport.protocol", "smtp");
    props.put("mail.smtp.port", PORT);
    props.put("mail.smtp.starttls.enable", "true");
    props.put("mail.smtp.auth", "true");
    Session session = Session.getDefaultInstance(props);
    MimeMessage msg = new MimeMessage(session);
    msg.setFrom(new InternetAddress(from, fromname));
    InternetAddress[] toAddress = new InternetAddress[to.length];
    for (int i = 0; i < to.length; i++) {
        toAddress[i] = new InternetAddress(to[i]);
    }
    for (int i = 0; i < toAddress.length; i++) {
        msg.addRecipient(Message.RecipientType.TO, toAddress[i]);
    }
    msg.setSubject(subject);
    msg.setContent(messageBody, "text/html");
    Transport transport = session.getTransport();
    try {
        System.out.println("Sending...");
        transport.connect(HOST, SMTP_USERNAME, SMTP_PASSWORD);
        transport.sendMessage(msg, msg.getAllRecipients());
        System.out.println("Email sent!");
    } catch (Exception ex) {
        System.out.println("The email was not sent.");
        System.out.println("Error message: " + ex.getMessage());
    } finally {
        transport.close();
    }
}

在此，我们在两种方法中使用相同的代码。 我想将通用代码放在另一种方法中。 我将尝试将通用代码放入另一个方法中，然后尝试调用该方法，但不适用于两个方法。 如果我们尝试在这两种方法中都调用一个通用方法，那么它将仅适用于一个方法。

请给我任何建议。

3 个答案:

答案 0 :(得分：1)

您似乎可以使用空数组编写第二种方法来使用第一种方法：

public static void sendMail(String[] to, String subject, String messageBody) throws Exception {
    sendMail(to, subject, messageBody, new String[]{""}. new String[]{""});
}

这会在cc和bcc数组中传递一个空字符串，以便您的其他方法将跳过该数组。

请注意，您将在此处保持对N​​ullPointerExceptions的了解：

if(cc[0] != "") { ... }

这是盲目的假设cc数组包含至少一个元素。 如果要使用一个空数组调用该方法，或者为cc或bcc调用null，则程序将引发异常。 在该if语句内部，您已经在使用cc.length，因此，如果cc.length为零，则不会添加CC地址。 该测试的更好实现可能是：

if (cc != null && cc.length > 0) {...}

此外，我不确定为什么您构建ccAddress数组只是为了丢弃它。 这是同一循环，用单个ccAddress对象替换ccAddress数组。

if(cc != null && cc.length > 0) {
    for (int i = 0; i < cc.length; i++) {
        InternetAddress ccAddress = new InternetAddress(cc[i]);
        msg.addRecipient(Message.RecipientType.CC, ccAddress);
    }
}

答案 1 :(得分：0)

您可以做的最简单的事情就是实现第二种方法，以便它以某种方式调用第一种，这样就不会添加任何抄送或密件抄送收件人。根据您当前的代码，它可以是：

public static void sendMail(String[] to, String subject, String body) {
    sendMail(to, subject, body, new Object[]{""}, new Object[]{""});
}

答案 2 :(得分：0)

您不必制作其他方法。参数计数较低的方法只调用参数计数较高的方法，其值为空，然后在“ real”方法中进行空检查。

public static void sendMail(String[] to, String subject, String messageBody, String[] cc, String[] bcc) throws Exception {
    Properties props = System.getProperties();
    props.put("mail.transport.protocol", "smtp");
    props.put("mail.smtp.port", PORT);
    props.put("mail.smtp.starttls.enable", "true");
    props.put("mail.smtp.auth", "true");
    Session session = Session.getDefaultInstance(props);
    MimeMessage msg = new MimeMessage(session);
    msg.setFrom(new InternetAddress(from, fromname));
    InternetAddress[] toAddress = new InternetAddress[to.length];
    for (int i = 0; i < to.length; i++) {
        toAddress[i] = new InternetAddress(to[i]);    
    }
    for (int i = 0; i < toAddress.length; i++) {
        msg.addRecipient(Message.RecipientType.TO, toAddress[i]);
    }
    msg.setSubject(subject);
    msg.setContent(messageBody, "text/html");
    if(cc != null && cc[0] != "") {
        InternetAddress[] ccAddress = new InternetAddress[cc.length];
        for (int i = 0; i < cc.length; i++) {
            ccAddress[i] = new InternetAddress(cc[i]);
        }
        for (int i = 0; i < ccAddress.length; i++) {
            msg.addRecipient(Message.RecipientType.CC, ccAddress[i]);
        }
    }
    if(bcc != null && bcc[0] != "") {
        InternetAddress[] bccAddress = new InternetAddress[bcc.length];
        for (int i = 0; i < bcc.length; i++) {
            bccAddress[i] = new InternetAddress(bcc[i]);
        }
        for (int i = 0; i < bccAddress.length; i++) {
            msg.addRecipient(Message.RecipientType.BCC, bccAddress[i]);
        }
    }
    Transport transport = session.getTransport();
    try {
        System.out.println("Sending...");
        transport.connect(HOST, SMTP_USERNAME, SMTP_PASSWORD);
        transport.sendMessage(msg, msg.getAllRecipients());
        System.out.println("Email sent!");
    } catch (Exception ex) {
        System.out.println("The email was not sent.");
        System.out.println("Error message: " + ex.getMessage());
    } finally {
        transport.close();
    }
}

public static void sendMail(String[] to, String subject, String messageBody) throws Exception {
    sendMail(to, subject, messageBody, null, null);
}
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