1. download java keyutil
https://java-keyutil.googlecode.com/files/keyutil-0.4.0.jar
2. run the following command
java -jar keyutil-0.4.0.jar --import --new-keystore trustStore.jks --import-pem-file ca-bundle.crt -p 123456
ca-bundle.crt to java truststore(e.g. trustStore.jks)
原文：http://www.cnblogs.com/jmbkeyes/p/4551101.html