I'm trying to execute simplest async REST controller using java.util.concurrent.Callable:
@RequestMapping("/AsyncRequest")
public Callable asyncRequest() {
return () -> {
Thread.sleep(3000);
return "reply";
};
}
Then I run http://localhost/AsyncRequest two times in browser. The first answer I get in 3 seconds, but the second just after 6 seconds. It seems like that the requests processed not asynchronously. Why this happen?
Spring Boot behavior really depends on version and configuration.
The following configuration and code works for me:
Starter
package com.stackoverflow.spring.boot.async;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.context.annotation.Import;
@Import(WebConfig.class)
@SpringBootApplication
public class WebMain {
private final SpringApplication application;
public WebMain() {
final SpringApplicationBuilder applicationBuilder = new SpringApplicationBuilder(WebMain.class);
application = applicationBuilder.build();
}
public SpringApplication getApplication() { return application; }
public static void main(final String[] args) {
new WebMain().getApplication().run(args);
}
}
Configuration
package com.stackoverflow.spring.boot.async;
import org.springframework.boot.context.embedded.ConfigurableEmbeddedServletContainer;
import org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizer;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
@Configuration
public class WebConfig extends WebMvcConfigurerAdapter implements EmbeddedServletContainerCustomizer
{
public void customize(final ConfigurableEmbeddedServletContainer container) {}
}
Controller
I've changed sleep time here to 6 second and added some payload into response.
package com.stackoverflow.spring.boot.async;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import java.util.Date;
import java.util.concurrent.Callable;
@Controller
public class AsyncController {
@RequestMapping(path = "/AsyncRequest", method = RequestMethod.GET)
@ResponseBody
public Callable<String> asyncRequest() {
return () -> {
final long currentThread = Thread.currentThread().getId();
final Date requestProcessingStarted = new Date();
Thread.sleep(6000L);
final Date requestProcessingFinished = new Date();
return String.format(
"request: [threadId: %s, started: %s - finished: %s]"
, currentThread, requestProcessingStarted, requestProcessingFinished);
};
}
}
pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.stackoverflow.spring.boot</groupId>
<artifactId>async</artifactId>
<packaging>jar</packaging>
<version>1.0-SNAPSHOT</version>
<properties>
<java.version>1.8</java.version>
<spring-boot.version>1.4.1.RELEASE</spring-boot.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-dependencies</artifactId>
<version>${spring-boot.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot</artifactId>
<version>${spring-boot.version}</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<version>${spring-boot.version}</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
<version>${spring-boot.version}</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.5.1</version>
<inherited>true</inherited>
<configuration>
<source>${java.version}</source>
<target>${java.version}</target>
</configuration>
</plugin>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>${spring-boot.version}</version>
<executions>
<execution>
<goals>
<goal>repackage</goal>
</goals>
<configuration>
<classifier>exec</classifier>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
Testing
java -version
java version "1.8.0_111"
Java(TM) SE Runtime Environment (build 1.8.0_111-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.111-b14, mixed mode)
--
mvn spring-boot:run
...
--
# start following command from different consoles:
curl http://localhost:8080/AsyncRequest
Results
request: [threadId: 33, started: 15:50:28 - finished: 15:50:34]
request: [threadId: 35, started: 15:50:29 - finished: 15:50:35]
request: [threadId: 37, started: 15:50:30 - finished: 15:50:36]
