4.4.3. @Readiness 注释示例

以下示例演示了如何检查与数据库的连接：如果数据库停机，就绪度检查报告错误。

@Readiness
@ApplicationScoped
public class DatabaseConnectionHealthCheck implements HealthCheck {

    @Inject
    @ConfigProperty(name = "database.up", defaultValue = "false")
    private boolean databaseUp;

    @Override
    public HealthCheckResponse call() {

        HealthCheckResponseBuilder responseBuilder = HealthCheckResponse.named("Database connection health check");

        try {
            simulateDatabaseConnectionVerification();
            responseBuilder.up();
        } catch (IllegalStateException e) {
            // cannot access the database
            responseBuilder.down()
                .withData("error", e.getMessage()); // pass the exception message
        }

        return responseBuilder.build();
    }

    private void simulateDatabaseConnectionVerification() {
        if (!databaseUp) {
            throw new IllegalStateException("Cannot contact database");
        }
    }
}