(Java) Send HTML Email with External CSS as Related Item

Demonstrates how to compose an HTML email with an external CSS file included as a related item and referenced by CID (Content-ID).

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import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    // The mailman object is used for sending and receiving email.
    CkMailMan mailman = new CkMailMan();

    // Use your SMTP server hostname.  This example uses office365, but it could be any SMTP server..
    mailman.put_SmtpHost("outlook.office365.com");
    mailman.put_SmtpPort(587);
    mailman.put_StartTLS(true);

    // Set the SMTP login/password
    mailman.put_SmtpUsername("OFFICE365-SMTP-LOGIN");
    mailman.put_SmtpPassword("OFFICE365-SMTP-PASSWORD");

    // Create a new email object
    CkEmail email = new CkEmail();
    email.put_Subject("HTML Email with embedded CSS");
    email.put_From("Chilkat Support <my-office365-user@mydomain.com>");
    email.AddTo("Chilkat Support","support@chilkatsoft.com");

    CkStringBuilder sbCss = new CkStringBuilder();
    boolean bCrlf = true;
    sbCss.AppendLine("body {",bCrlf);
    sbCss.AppendLine("    background-color: powderblue;",bCrlf);
    sbCss.AppendLine("}",bCrlf);
    sbCss.AppendLine("h1 {",bCrlf);
    sbCss.AppendLine("    color: blue;",bCrlf);
    sbCss.AppendLine("}",bCrlf);
    sbCss.AppendLine("p {",bCrlf);
    sbCss.AppendLine("    color: red;",bCrlf);
    sbCss.AppendLine("}",bCrlf);

    // It's possible to add a CSS file directly by calling AddRelatedFile.
    // This example will add the CSS from a string.
    String filenameInHtml = "styles.css";
    String contentIdCss = email.addRelatedString(filenameInHtml,sbCss.getAsString(),"utf-8");
    if (email.get_LastMethodSuccess() != true) {
        System.out.println(email.lastErrorText());
        return;
        }

    // The src attribute for the image tag is set to the contentIdCss:
    CkStringBuilder sbHtml = new CkStringBuilder();
    sbHtml.AppendLine("<!DOCTYPE html>",bCrlf);
    sbHtml.AppendLine("<html>",bCrlf);
    sbHtml.AppendLine("<head>",bCrlf);
    sbHtml.AppendLine("  <link rel=\"stylesheet\" href=\"cid:CONTENT_ID_CSS\">",bCrlf);
    sbHtml.AppendLine("</head>",bCrlf);
    sbHtml.AppendLine("<body>",bCrlf);
    sbHtml.AppendLine("",bCrlf);
    sbHtml.AppendLine("<h1>This is a heading</h1>",bCrlf);
    sbHtml.AppendLine("<p>This is a paragraph.</p>",bCrlf);
    sbHtml.AppendLine("",bCrlf);
    sbHtml.AppendLine("</body>",bCrlf);
    sbHtml.AppendLine("</html>",bCrlf);

    int numReplacements = sbHtml.Replace("CONTENT_ID_CSS",contentIdCss);

    email.SetHtmlBody(sbHtml.getAsString());

    boolean success = mailman.SendEmail(email);
    if (success != true) {
        System.out.println(mailman.lastErrorText());
        }
    else {
        System.out.println("Mail Sent!");
        }
  }
}