Dropbox V1 to V2 migration Error in Spring Web MVC Project - spring

Question

As per Dropbox API V2(dropbox-core-sdk-2.1.1.jar) tutorial, I have been migrated in Java console application as shown in the following code.
import java.io.IOException;
import com.dropbox.core.DbxException;
import com.dropbox.core.DbxRequestConfig;
import com.dropbox.core.v2.DbxClientV2;
import com.dropbox.core.v2.files.ListFolderResult;
import com.dropbox.core.v2.files.Metadata;
public class Main {
private static final String ACCESS_TOKEN = "xxxx-xxxx-xxxx";
public static void main(String args[]) throws DbxException, IOException {
DbxRequestConfig config = new DbxRequestConfig("");
DbxClientV2 client = new DbxClientV2(config, ACCESS_TOKEN);
try {
ListFolderResult result = client.files().listFolder("");
while (true) {
for (Metadata metadata : result.getEntries()) {
System.out.println(metadata.getPathLower());
}
if (!result.getHasMore()) {
break;
}
result = client.files().listFolderContinue(result.getCursor());
}
} catch (Exception er) {
er.printStackTrace();
}
}
}
Above code compiled and run perfectly. But the same code I have been implemented in the Spring web application. But it is not working, only thrown the following exception.
Aug 26, 2016 3:18:30 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [dispatcher] in context with path [/dropboxz] threw exception [Handler processing failed; nested exception is java.lang.ExceptionInInitializerError] with root cause
java.lang.RuntimeException: Error loading version from resource "sdk-version.txt": Text doesn't follow expected pattern: "${project.version}"
at com.dropbox.core.DbxSdkVersion.loadVersion(DbxSdkVersion.java:66)
at com.dropbox.core.DbxSdkVersion.<clinit>(DbxSdkVersion.java:17)
at com.dropbox.core.DbxRequestUtil.buildUserAgentHeader(DbxRequestUtil.java:144)
at com.dropbox.core.DbxRequestUtil.addUserAgentHeader(DbxRequestUtil.java:129)
at com.dropbox.core.DbxRequestUtil.startPostRaw(DbxRequestUtil.java:226)
at com.dropbox.core.v2.DbxRawClientV2$1.execute(DbxRawClientV2.java:100)
at com.dropbox.core.v2.DbxRawClientV2.executeRetriable(DbxRawClientV2.java:252)
at com.dropbox.core.v2.DbxRawClientV2.rpcStyle(DbxRawClientV2.java:97)
at com.dropbox.core.v2.files.DbxUserFilesRequests.listFolder(DbxUserFilesRequests.java:629)
at com.dropbox.core.v2.files.DbxUserFilesRequests.listFolder(DbxUserFilesRequests.java:656)
at com.doj.spring4.controller.HelloSpring4Controller.viewDropboxLoginScreen(HelloSpring4Controller.java:34)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:176)
at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:445)
at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:433)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:947)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:878)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:946)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:837)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:822)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:528)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1099)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:670)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1520)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1476)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Unknown Source)
Please give the solution.

Answer 1

That error comes from here:
https://github.com/dropbox/dropbox-sdk-java/blob/3cfa878e5d73f06ed4782c8833b229838fd21472/src/main/java/com/dropbox/core/DbxSdkVersion.java#L66
So, it looks like your "sdk-version.txt" file contains "${project.version}" when a number is expected.
The sdk-version.txt file does initially contain that string:
https://github.com/dropbox/dropbox-sdk-java/blob/af7a43e691dccc95eca0a591f7d61250c16db314/src/main/resources/sdk-version.txt
However, it should be replaced during the gradle build:
https://github.com/dropbox/dropbox-sdk-java/blob/af7a43e691dccc95eca0a591f7d61250c16db314/build.gradle#L96
So, it sounds like that gradle build isn't happening in your Spring web application.