Configuration

Configuration objects

You can use @ConfigurationProperties to bind Java objects to properties. If you define the prefix attribute, it defines the subtree of the properties for the mapping.

@ConfigurationProperties(prefix = "app")
public class AppConfig {
    private Database database;
    private Service service;

    public static class Database {
        private String url;
    }

    public static class Service {
        private String name;
    }
}

app.database.url=localhost:3032
app.service.name=AService

Use dynamic ports in tests

Do not use static fix ports in your tests. Use SpringBootTest.WebEnvironment.RANDOM_PORT. Then you can access the port with the @LocalServerPort annotation

@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
public class ApplicationTest {

   @LocalServerPort
   private int serverPort;  // Contains the random server port

   @Test
   void test() {
      Assertions.assertTrue(serverPort > 0);
   }
}

Generic exception handling

If you put the annotation @ControllerAdvice on a class, it will work as a global class for handling exceptions. @RestController is similar but designed for RestController with response in JSON or XML.

@RestControllerAdvice
public class FileNotFoundHandler {

    @ResponseStatus(HttpStatus.NO_CONTENT)
    @ExceptionHandler(NoSuchElementException.class)
    public void handleNotFoundError() {
    }
}

Use dependency check plugin

Use the OWASP dependency check Maven plugin to scan your libraries for security issues.

Dependency Check Maven Plugin

Structured logs

Structured logging generates log output in a consistent, machine-readable format. There are several formats defined. e.g.

• ecs: Elastic Common Schema format
• logstash: Logstash format

To enable it. Add the following property to your application properties

logging:
  structured:
    format:
      console: ecs

or for files

logging:
  structured:
    format:
      file: ecs
  file:
    name: log.json