Java
Force Quoted-Printable Encoding for Email

Demonstrates how to force the quoted-printable encoding for email.
Chilkat Java Downloads

Java
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[])
  {
    boolean success = false;

    CkEmail email = new CkEmail();

    email.put_Subject("test");
    email.put_From("bob@example.com");
    email.AddTo("Mary","mary@example.com");

    // Add plain-text and HTML alternative bodies.
    // Include some "=" chars so we can see the quoted-printable encoding when used..
    email.AddPlainTextAlternativeBody("This is a test == Hello World!");
    email.AddHtmlAlternativeBody("<html><body>This is a test == Hello World!</body></html>");

    // Examine the MIME of the email to see that it does not use quoted-printable.
    // (If the email contained non-usascii chars, it would automatically use quoted-printable.)
    CkMailMan mailman = new CkMailMan();
    System.out.println(mailman.renderToMime(email));

    // Here is the MIME before forcing quoted-printable.
    // Notice the Content-Transfer-Encoding is "7bit" (not "quoted-printable")

    // MIME-Version: 1.0
    // Date: Tue, 29 Sep 2020 12:26:52 -0500
    // Message-ID: <CF274FC0A2F82B98A05B7507DF7DFB966A2C0EB8@CHILKATSLICE>
    // Content-Type: multipart/alternative;
    //  boundary="------------080901080902080000030208"
    // X-Priority: 3 (Normal)
    // Subject: test
    // From: bob@example.com
    // To: Mary <mary@example.com>
    // 
    // --------------080901080902080000030208
    // Content-Transfer-Encoding: 7bit
    // Content-Type: text/plain; charset=us-ascii; format=flowed
    // 
    // This is a test == Hello World!
    // --------------080901080902080000030208
    // Content-Transfer-Encoding: 7bit
    // Content-Type: text/html; charset=us-ascii
    // 
    // <html><body>This is a test == Hello World!</body></html>
    // --------------080901080902080000030208--

    System.out.println("----");

    // To force quoted-printable, set the Content-Transfer-Encoding header.
    // It will automatically propagate as needed to the MIME sub-parts.
    email.AddHeaderField("Content-Transfer-Encoding","quoted-printable");
    System.out.println(mailman.renderToMime(email));

    // MIME-Version: 1.0
    // Date: Tue, 29 Sep 2020 12:26:52 -0500
    // Message-ID: <F36B276E3A720FE5111D15CE9142C8909E1F5AB9@CHILKATSLICE>
    // Content-Type: multipart/alternative;
    //  boundary="------------080901080902080000030208"
    // X-Priority: 3 (Normal)
    // Subject: test
    // From: bob@example.com
    // To: Mary <mary@example.com>
    // 
    // --------------080901080902080000030208
    // Content-Transfer-Encoding: quoted-printable
    // Content-Type: text/plain; charset=us-ascii; format=flowed
    // 
    // This is a test =3D=3D Hello World!
    // --------------080901080902080000030208
    // Content-Transfer-Encoding: quoted-printable
    // Content-Type: text/html; charset=us-ascii
    // 
    // <html><body>This is a test =3D=3D Hello World!</body></html>
    // --------------080901080902080000030208--
  }
}