Using Java to Operate IBM Cloudant

IBM Cloudant is a hosted NoSQL database solution based on Apache CouchDB and provides hosted services. Using Java to operate Cloudant can be achieved through the Java SDK. This tutorial will demonstrate how to use Java for data insertion, modification, querying, and deletion. 1. Add Maven dependency Firstly, the following Maven dependencies need to be added to the pom.xml file of the project: <dependency> <groupId>com.cloudant</groupId> <artifactId>cloudant-client</artifactId> <version>2.17.0</version> </dependency> 2. Create Cloudant instance To use Cloudant, you need to create a Cloudant instance. You can use the service credentials (username, password, and URL) in IBM Cloud to create an instance: String username = "<your-username>"; String password = "<your-password>"; String url = "<your-url>"; CloudantClient client = ClientBuilder.account(username) .username(username) .password(password) .url(url) .build(); 3. Data insertion Next, we will demonstrate how to insert a document (JSON object) into the Cloudant database. //Get Database Objects Database db = client.database("mydatabase", false); //Create a JSON object JsonObject json = new JsonObject(); json.addProperty("name", "John Doe"); json.addProperty("age", 30); //Insert Document Response response = db.save(json); if (response.getError() == null) { System. out. println ("Insert successful"); } 4. Data modification Cloudant uses documentation for_ ID and_ The rev attribute identifies each document. To modify a document, you need to first retrieve it and update its content before saving it. //Obtain the document to be modified Document doc = db.find(Document.class, "<document-id>"); //Update document content doc.set("name", "Jane Smith"); //Save the modified document Response response = db.update(doc); if (response.getError() == null) { System. out. println ("modified successfully"); } 5. Data Query Using Cloudant's view function allows for easy data querying. Firstly, we need to create a view in the database. //Create a Software design description and define views DesignDocument designDoc = new DesignDocument(); designDoc.setId("_design/mydesigndoc"); View view = new View(); view.setMap("function (doc) { emit(doc.name, doc.age); }"); designDoc.addView("myview", view); db.save(designDoc); Then, the view can be used to query the specified data. //Query View ViewRequest<String, String> request = db.getViewRequestBuilder("mydesigndoc", "myview") .newRequest(Key.Type.STRING, KeyValue.Type.STRING) .build(); ViewResponse<String, String> response = request.getResponse(); List<Row<String, String>> rows = response.getRows(); for (Row<String, String> row : rows) { System.out.println(row.getKey() + ": " + row.getValue()); } 6. Data deletion To delete a document, use the db. remove (Document doc) method and pass the document object. //Obtain the document to be deleted Document doc = db.find(Document.class, "<document-id>"); //Delete Document Response response = db.remove(doc); if (response.getError() == null) { System. out. println ("deleted successfully"); } This is the complete example code of how to use Java to operate IBM Cloudant for data insertion, modification, query, and deletion. According to the actual situation, the above code can be modified and adapted.