Java Servlets: Tomcat server find MongoDB classes and packages

Question

I'm trying to connect a MongoDB database to Tomcat. I downloaded the three 3.10.1 Java Driver jar files, mongodb-driver-3.10.1-javadoc.jar , mongodb-driver-3.10.1-sources.jar , and mongodb-driver-3.10.1.jar . I added them to WEB-INF\\lib . I also added a MongoDB resource in META-INF\\context.xml , and a resource reference in WEB-INF\\web.xml . Still, Tomcat is saying that the package com.mongodb does not exist. Does anyone have a fix for this?

My context.xml file:

<Context reloadable="true">

    <WatchedResource>WEB-INF/web.xml</WatchedResource>

    <Resource name="mongodb/MyMongoClient"
          auth="Container"
          type="com.mongodb.MongoClient"
          closeMethod="close"
          factory="com.mongodb.client.jndi.MongoClientFactory"
          singleton="true"
          connectionString="mongodb://localhost:80"/>

</Context>

My web.xml file:

<?xml version="1.0" encoding="ISO-8859-1"?>

<web-app version="3.0"
    xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">

    <servlet>
        <servlet-name>Test</servlet-name>
        <servlet-class>Test</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>Test</servlet-name>
        <url-pattern>/test</url-pattern>
    </servlet-mapping>

    <servlet>
        <servlet-name>TestCheck</servlet-name>
        <servlet-class>TestCheck</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>TestCheck</servlet-name>
        <url-pattern>/testCheck</url-pattern>
    </servlet-mapping>

    <resource-ref>
        <res-ref-name>
            mongodb/MyMongoClient
        </res-ref-name>
        <res-type>
            com.mongodb.MongoClient
        </res-type>
        <res-auth>
            Container
        </res-auth>
    </resource-ref>

</web-app>

My Test.java file:

import javax.servlet.annotation.*;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.ServletException;

import java.io.IOException;


import com.mongodb.MongoClient;
import com.mongodb.MongoClientURI;

import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBObject;
import com.mongodb.BasicDBObject;

@WebServer("/test")
public class Test extends HttpServlet{

    @Override
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {


        //Connect
        MongoClient mongoClient = new MongoClient(new MongoClientURI("mongodb://localhost:80"));


        DB database = mongoClient.getDB("testDB");
        DBCollection collection = database.getCollection("testCollection");

        DBObject testDoc = new BasicDBObject("_id", "This is a test");

        collection.insert(testDoc);

        //close
        mongoClient.close();

    }

}

And finally, the output from the command prompt after trying to compile:

Test.java:11: error: package com.mongodb does not exist
import com.mongodb.MongoClient;
                  ^
Test.java:12: error: package com.mongodb does not exist
import com.mongodb.MongoClientURI;
                  ^
Test.java:14: error: package com.mongodb does not exist
import com.mongodb.DB;
                  ^
Test.java:15: error: package com.mongodb does not exist
import com.mongodb.DBCollection;
                  ^
Test.java:16: error: package com.mongodb does not exist
import com.mongodb.DBObject;
                  ^
Test.java:17: error: package com.mongodb does not exist
import com.mongodb.BasicDBObject;
                  ^
Test.java:19: error: cannot find symbol
@WebServer("/test")
 ^
  symbol: class WebServer
Test.java:27: error: cannot find symbol
                MongoClient mongoClient = new MongoClient(new MongoClientURI("mo
ngodb://localhost:80"));
                ^
  symbol:   class MongoClient
  location: class Test
Test.java:27: error: cannot find symbol
                MongoClient mongoClient = new MongoClient(new MongoClientURI("mo
ngodb://localhost:80"));
                                              ^
  symbol:   class MongoClient
  location: class Test
Test.java:27: error: cannot find symbol
                MongoClient mongoClient = new MongoClient(new MongoClientURI("mo
ngodb://localhost:80"));
                                                              ^
  symbol:   class MongoClientURI
  location: class Test
Test.java:30: error: cannot find symbol
                DB database = mongoClient.getDB("testDB");
                ^
  symbol:   class DB
  location: class Test
Test.java:31: error: cannot find symbol
                DBCollection collection = database.getCollection("testCollection
");
                ^
  symbol:   class DBCollection
  location: class Test
Test.java:33: error: cannot find symbol
                DBObject testDoc = new BasicDBObject("_id", "Hello!");
                ^
  symbol:   class DBObject
  location: class Test
Test.java:33: error: cannot find symbol
                DBObject testDoc = new BasicDBObject("_id", "Hello!");
                                       ^
  symbol:   class BasicDBObject
  location: class Test
14 errors

Any help would be much appreciated.

Answer 1

It's not Tomcat, it's compiler. To add the MongoDB libraries to Tomcat is needed to be able to run the (web)app, but in order to compile it you have to add them to the compiler's classpath. If you use the javac directly, see the -cp switch (or have a look here ), if you use some build system (like Maven), look into its documentation how to add a compile dependency.