我这边java在没有通过ssl连接mqtt的时候是可以连接的(可以订阅与发布)，

但是通过ssl就不行了，发现是读取证书的时候出错了，错误是这样的：

java.security.cert.CertificateException: Unable to initialize, java.io.IOException: extra data given to DerValue constructor

at sun.security.x509.X509CertImpl.<init>(Unknown Source)

at sun.security.provider.X509Factory.engineGenerateCertificate(Unknown Source)

at java.security.cert.CertificateFactory.generateCertificate(Unknown Source)

at com.test.mqtt.AppTest.main(AppTest.java:51)

Caused by: java.io.IOException: extra data given to DerValue constructor

at sun.security.util.DerValue.init(Unknown Source)

at sun.security.util.DerValue.<init>(Unknown Source)

at sun.security.util.DerValue.<init>(Unknown Source)

... 4 more

具体代码是：

CertificateFactory cf;

try {

cf = CertificateFactory.getInstance("X.509");

FileInputStream crtIn = new FileInputStream("D:\\test\\client.crt");

X509Certificate caCert = (X509Certificate) cf.generateCertificate(crtIn);

//Certificate caCert =  cf.generateCertificate(crtIn);

crtIn.close();

} catch (CertificateException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

关键问题是ca能读但是读取这个证书的时候就报错了。。。。。哪位大神帮我解决一下问题，拜托了