如何修复 Android 上 Spongy Castle 的错误：找不到类 java.awt.datatransfer.DataFlavor

我使用 lib Spongy Castle 在 Android 上对邮件进行签名和加密这个例子 https://github.com/rtyley/spongycastle/blob/spongy-master/scmail-jdk15on/src/main/java/org/spongycastle/mail/smime/examples/SendSignedAndEncryptedMail.java.

            /* Add BC */
            Security.addProvider(new BouncyCastleProvider());
            /* Open the keystore */
            KeyStore keystore = KeyStore.getInstance("PKCS12", "SC");
            keystore.load(new FileInputStream(pkcs12Keystore),
                    password.toCharArray());
            Certificate[] chain = keystore.getCertificateChain(keyalias);

            /* Get the private key to sign the message with */
            PrivateKey privateKey = (PrivateKey) keystore.getKey(keyalias,
                    password.toCharArray());

            /* Create the SMIMESignedGenerator */
            SMIMECapabilityVector capabilities = new SMIMECapabilityVector();
            capabilities.addCapability(SMIMECapability.dES_EDE3_CBC);
            capabilities.addCapability(SMIMECapability.rC2_CBC, 128);
            capabilities.addCapability(SMIMECapability.dES_CBC);

            ASN1EncodableVector attributes = new ASN1EncodableVector();
            attributes.add(new SMIMEEncryptionKeyPreferenceAttribute(
                    new IssuerAndSerialNumber(new X500Name(
                            ((X509Certificate) chain[0]).getIssuerDN()
                                    .getName()), ((X509Certificate) chain[0])
                            .getSerialNumber())));
            attributes.add(new SMIMECapabilitiesAttribute(capabilities));

            SMIMESignedGenerator signer = new SMIMESignedGenerator();
            signer.addSignerInfoGenerator(new JcaSimpleSignerInfoGeneratorBuilder()
                    .setProvider("SC")
                    .setSignedAttributeGenerator(new AttributeTable(attributes))
                    .build("DSA".equals(privateKey.getAlgorithm()) ? "SHA1withDSA"
                            : "MD5withDSA", privateKey,
                            (X509Certificate) chain[0]));

            /* Add the list of certs to the generator */
            List certList = new ArrayList();
            certList.add(chain[0]);
            Store certs = new JcaCertStore(certList);
            signer.addCertificates(certs);

            /* Sign the message */
            MimeMultipart mm = signer.generate(originalMessage, "SC");
            signedMessage = new MimeMessage(session);

            /* Set all original MIME headers in the signed message */
            Enumeration headers = originalMessage.getAllHeaderLines();
            while (headers.hasMoreElements()) {
                signedMessage.addHeaderLine((String) headers.nextElement());
            }

            /* Set the content of the signed message */
            signedMessage.setContent(mm);
            signedMessage.saveChanges();

            ByteArrayOutputStream out = new ByteArrayOutputStream();
            signedMessage.writeTo(out);

            FileOutputStream f = new FileOutputStream(new File(
                    "/sdcard/MobilePKI/out.txt"));
            f.write(out.toByteArray());
            f.close();

当我运行我的应用程序时，它返回以下错误：

11-13 08:54:11.867: E/dalvikvm(13188): Could not find class '[Ljava.awt.datatransfer.DataFlavor;', referenced from method org.spongycastle.mail.smime.handlers.multipart_signed.<clinit>
11-13 08:54:11.890: E/AndroidRuntime(13188): FATAL EXCEPTION: main
11-13 08:54:11.890: E/AndroidRuntime(13188): java.lang.VerifyError: org.spongycastle.mail.smime.handlers.multipart_signed
11-13 08:54:11.890: E/AndroidRuntime(13188):    at java.lang.Class.newInstanceImpl(Native Method)
11-13 08:54:11.890: E/AndroidRuntime(13188):    at java.lang.Class.newInstance(Class.java:1409)
11-13 08:54:11.890: E/AndroidRuntime(13188):    at javax.activation.MailcapCommandMap.getDataContentHandler(MailcapCommandMap.java:609)
11-13 08:54:11.890: E/AndroidRuntime(13188):    at javax.activation.MailcapCommandMap.createDataContentHandler(MailcapCommandMap.java:563)
11-13 08:54:11.890: E/AndroidRuntime(13188):    at javax.activation.DataHandler.getDataContentHandler(DataHandler.java:626)
11-13 08:54:11.890: E/AndroidRuntime(13188):    at javax.activation.DataHandler.writeTo(DataHandler.java:329)
11-13 08:54:11.890: E/AndroidRuntime(13188):    at javax.mail.internet.MimeBodyPart.writeTo(MimeBodyPart.java:1403)
11-13 08:54:11.890: E/AndroidRuntime(13188):    at javax.mail.internet.MimeMessage.writeTo(MimeMessage.java:1745)
11-13 08:54:11.890: E/AndroidRuntime(13188):    at javax.mail.internet.MimeMessage.writeTo(MimeMessage.java:1721)

Spongy Castle lib的源代码似乎需要java.awt.datatransfer：

package org.spongycastle.mail.smime.handlers;

import org.spongycastle.mail.smime.SMIMEStreamingProcessor;

import javax.activation.ActivationDataFlavor;
import javax.activation.DataContentHandler;
import javax.activation.DataSource;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.internet.ContentType;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMultipart;

import java.awt.datatransfer.DataFlavor;

import java.io.BufferedInputStream;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Enumeration;

(link: https://github.com/rtyley/spongycastle/blob/spongy-master/scmail-jdk15on/src/main/java/org/spongycastle/mail/smime/handlers/multipart_signed.java https://github.com/rtyley/spongycastle/blob/spongy-master/scmail-jdk15on/src/main/java/org/spongycastle/mail/smime/handlers/multipart_signed.java)

我认为它必须导入包 java.awt 并且我将 rt.jar （包括 java.awt.*）导入到我的项目中，但它仍然有这个错误。

我修正了我的错误：
+ 我下载了源代码海绵城堡库 https://github.com/rtyley/spongycastle
+ 替换行“import java.awt.datatransfer.DataFlavor;”通过“导入 myjava.awt.datatransfer.DataFlavor;” （包 myjava.awt.datatransfer 包含在附加库 http://code.google.com/p/javamail-android/downloads/list)
+ 重建 spongycastle 库
+ 使用新的 spongycastle 库