Configuring timeouts is essential for building resilient Spring applications. When you set clear time limits for operations like database queries or external API calls, you prevent your app from waiting indefinitely and becoming unresponsive. By learning how to configure timeouts, you ensure that your application can quickly recover from slow or failing services, maintain good user experience, and avoid resource bottlenecks. In this chapter, you will discover practical ways to set up and manage timeouts in your Spring projects to boost reliability and performance.

Configuring Timeouts in Spring Applications

Configuring timeouts helps your Spring applications stay responsive and avoid waiting too long for slow operations. You can set timeouts for HTTP requests, database calls, or any operation that might take too long. Here’s how you can set up timeouts in common Spring scenarios.

Setting a Timeout for RestTemplate

RestTemplate is often used to make HTTP calls. You should set both connection and read timeouts to prevent your app from hanging if a remote service is slow or unavailable.

Step 1: Create a RestTemplate bean with custom timeouts.

@Bean
public RestTemplate restTemplate() {
    HttpComponentsClientHttpRequestFactory factory = new HttpComponentsClientHttpRequestFactory();
    factory.setConnectTimeout(5000); // 5 seconds
    factory.setReadTimeout(3000);    // 3 seconds
    return new RestTemplate(factory);
}

Step 2: Use this RestTemplate in your service to make HTTP calls. If a request takes longer than the specified time, a timeout exception is thrown.

Setting a Timeout for WebClient

WebClient is a non-blocking, reactive HTTP client. You can set timeouts using the responseTimeout option.

Step 1: Create a WebClient bean with a response timeout.

@Bean
public WebClient webClient() {
    return WebClient.builder()
        .clientConnector(
            new ReactorClientHttpConnector(
                HttpClient.create()
                    .responseTimeout(Duration.ofSeconds(2))
            )
        )
        .build();
}

Step 2: Use this WebClient to make HTTP calls. If the server does not respond within the timeout period, a timeout error occurs.

Setting a Timeout for Database Connections

You can set timeouts for database connections in your application.properties:

spring.datasource.hikari.connection-timeout=5000

This setting ensures that if a database connection cannot be established within 5 seconds, an exception is thrown.