面试向：SpringData MongoDB

还是那一套：
加spring data mongoDB 的dependencies 在Pom.xml里面。
然后config mongoDB by add the configration class:

@Configuration
public class AppConfig {
 public @Bean MongoClient mongoClient() {
  return MongoClients.create('mongodb://localhost:27017');
 }
}

1. what’s mongoDBTemplate class:
   it provide conveniene operations to create, update, delete and read mongoDB database
   also it can mapping domain objects and mongoDB documents.
   the exception handling mechanism is very implemented(originally from mongoDB driver.)

2. ways to initialize mongoDBTemplate class?
   MongoTemplate(MongoClient mongoClient, String databaseName) - Takes MongoClient object and default database name.
   MongoTemplate(MongoDatabaseFactory mongoFactory) - Takes a MongoDataBaseFactory object that encapsulates MongoClient, database, and its credentials.

3. CRUD operation

MongoTemplate mongoTemplate = new MongoTemplate(MongoClients.create(), 'database');
//Create MongoDB document
Website w = new Website('interviewgrid','www.interviewgrid.com');
mongoTemplate.insert(w);
//find document
w = findById('interviewgrid',Website.class);
//update document
mongoTemplate.updateFirst(query(where('id')is('interviewgrid')),update('url','http://www.interviewgrid.com'), Website.class);
//delete document
mongoTemplate.remove(w);

看到了吗 很容易使用。所以不用太慌。