Java

Connect a Java application to TeselaDB with the official MongoDB driver for Java. TeselaDB presents itself as a mongos, so the driver works unchanged.

Requirements

• Java 11 or later and Maven or Gradle.
• The address of one or more nodes, a user with readWrite on the database and the pki/ca.pem file of the cluster.

Install the driver

<dependency>
  <groupId>org.mongodb</groupId>
  <artifactId>mongodb-driver-sync</artifactId>
  <version><!-- the latest driver version --></version>
</dependency>

Store the connection string

Put the string in an environment variable instead of writing it in the code:

export TESELADB_URI="mongodb://user:<password>@node-01:27017,node-02:27017/shop?tls=true"

Add the CA to a trust store

The Java driver does not read tlsCAFile from the string. Put the cluster CA in a trust store with keytool and give that store to the JVM, together with its password, in the javax.net.ssl.trustStore and javax.net.ssl.trustStorePassword properties when you start your application:

keytool -importcert -alias teseladb -file ca.pem -keystore teseladb.jks -storepass <secret>
java -Djavax.net.ssl.trustStore=teseladb.jks -Djavax.net.ssl.trustStorePassword=<secret> -jar app.jar

In the connection string of your application keep only the tls=true option, without tlsCAFile.

Write and read a document

try (MongoClient client = MongoClients.create(System.getenv("TESELADB_URI"))) {
    MongoCollection<Document> orders = client.getDatabase("shop").getCollection("orders");
    orders.insertOne(new Document("total", 149.5));
    System.out.println(orders.countDocuments());
}

Check

The program prints the number of documents in orders, which grows by one each time you run it.

Common problems

• The connection closes before authenticating because tls=true is missing from the string.
• The driver does not trust the node certificate because it does not have the CA of this cluster.

See also

• Connection string and options
• Read and write documents