Spring autowire custom @ConfigurationProperties object by prefix

Question

I would like to achieve not-trivial bean injection implementation.

I have a custom properties file:

@Getter
@Setter
@ConfigurationProperties
public class DatabaseProperties {
  private String url;
  private String username;
  private String password;
}

I Here is the configuration file:

@Configuration
@EnableConfigurationProperties(DatabaseProperties.class)
public class DBConfig {

  @Bean
  @ConfigurationProperties(prefix = "datasource.database1")
  public JdbcTemplate jdbcTemplateDatabase1(DatabaseProperties databaseProperties) {
    DataSource dataSource = new DriverManagerDataSource(
            databaseProperties.getUrl(),
            databaseProperties.getUsername(),
            databaseProperties.getPassword());
    return new JdbcTemplate(dataSource);
  }

  @Bean
  @ConfigurationProperties(prefix = "datasource.database2")
  public JdbcTemplate jdbcTemplateDatabase2(DatabaseProperties databaseProperties) {
    DataSource dataSource = new DriverManagerDataSource(
            databaseProperties.getUrl(),
            databaseProperties.getUsername(),
            databaseProperties.getPassword());
    return new JdbcTemplate(dataSource);
  }
}

The goal I want to achieve is to instantiate a new DatabaseProperties instance based on prefix.

There are two possible solutions:

• create two beans of type DatabaseProperties using corresponding prefixes and two JdbcTemplate beans where parameter is qualified DatabaseProperties bean accordingly.
• in each JdbcTemplate bean provide 3 parameters (String url, String username, String password) and inject them through @Value

BUT Is it possible to get rid of creating DatabaseProperties beans for each JdbcTemplate or using @Value ?

Answer 1

You don't need create a DatabaseProperties. Spring already does this for us on datasources and proprierties variable

@Configuration
public class ConfigDataSource {


    @Bean("datasource-1")  // this name will qualify on @autowired
    @ConfigurationProperties(prefix="spring.datasource.yourname-datasource-1") // this is the name for the prefix for datasource on .properties settings
    public DataSource dataSourcePostgres() {
        return DataSourceBuilder.create().build();
    }
    
    
    @Bean("datasource-2")  // this name will qualify on @autowired
    @ConfigurationProperties(prefix="spring.datasource.yourname-datasource-2") // this is the name for the prefix for datasource on .properties settings
    public DataSource dataSourceMySql() {
        return DataSourceBuilder.create().build();
    }
    
}

.properties

# Its required use the same name declared in bean
spring.datasource.yourname-datasource-1.url=...
spring.datasource.yourname-datasource-1.jdbcUrl=${spring.datasource.yourname-datasource-1}
spring.datasource.yourname-datasource-1.username=user
spring.datasource.yourname-datasource-1.password=pass
spring.datasource.yourname-datasource-1.driver-class-name=your.driver

spring.datasource.yourname-datasource-2.url=...
spring.datasource.yourname-datasource-2.jdbcUrl=${spring.datasource.yourname-datasource-2}
spring.datasource.yourname-datasource-2.username=user
spring.datasource.yourname-datasource-2.password=pass
spring.datasource.yourname-datasource-2.driver-class-name=your.driver

using on services

@Awtowired
@Qualifier("datasource-1")
private DataSource dataSource1;

@Awtowired
@Qualifier("datasource-2")
private DataSource dataSource2;

public testJdbcTemplate(){
     // You can qualifier JdbcTemplate below on bean and not necessary need instance on service
     JdbcTemplate jdbcTemplateDatasource1 = new JdbcTemplate(dataSource1);
     JdbcTemplate jdbcTemplateDatasource2 = new JdbcTemplate(dataSource2);
}