如何连接到 postgres 并使用 r2dbc 执行查询

Question

I'm trying to write a simple function which will connect to postgres and execute a select statement.

PostgresqlConnectionFactory connectionFactory = new PostgresqlConnectionFactory(
        PostgresqlConnectionConfiguration.builder()
            .host("localhost")
            .port(5432)
            .database("MyDB")
            .username("username")
            .password("password").build());



DatabaseClient client = DatabaseClient.create(connectionFactory);

Flux<Map<String, Object>> result = client.execute("select * from table").fetch().all();

result.map(s -> {
  System.out.println(s);
  return null;
});

The above piece of code isn't printing anything. There is no error as well. I can connect to DB using the same credentials. What is missing in the code to stream data from DB?

Answer 1

Create the configuration class which is similar to the below code to connect to the PostgreSQL database

@Configuration
@EnableR2dbcRepositories
public class DatabaseConfig extends AbstractR2dbcConfiguration {

    @Override
    public ConnectionFactory connectionFactory() {
        return ConnectionFactories.get("r2dbc:postgresql://localhost:5432/DATABASE_NAME");
    }

}