Develop Reference

Spring boot how to use #PostConstruct correctly

Spring boot 2.5.4 I used #PostConstruct for the very first time in my service class. As following:-
#Slf4j
#Service
#AllArgsConstructor
public class FileMonitorService {
private final AppProperties appProperties;
private final WatchService watchService;
private final RestTemplate restTemplate;
#PostConstruct
#Async
public void startMonitoring() {
FileUtils.setAppProperties(appProperties);
FileUtils.setRestTemplate(restTemplate);
FileUtils.readFilesForDirectory();
log.info("START_MONITORING");
try {
WatchKey key;
while ((key = watchService.take()) != null) {
for (WatchEvent<?> event : key.pollEvents()) {
log.info("Event kind: {}; File affected: {}", event.kind(), event.context());
if((event.kind() == StandardWatchEventKinds.ENTRY_CREATE ||
event.kind() == StandardWatchEventKinds.ENTRY_MODIFY) &&
event.context().toString().contains(".xml")){
try {
restTemplateRequest(event.context().toString()+" processing");
FileUtils.readXml(Path.of(FileUtils.getFileAbsolutePath(appProperties.getDataIn()),
event.context().toString()));
}catch (Exception e){
log.error("startMonitoring Exception: "+e.getMessage());
}
}
}
key.reset();
}
} catch (InterruptedException e) {
log.warn("startMonitoring: interrupted exception for monitoring service: "+e.getMessage());
}
}
}
This method is called as soon as app launched. That is my requirements to process all file as soon as the app starts. I have controller as following:-
#RestController
#RequestMapping("/xml")
public class FileController {
#Autowired
FileMonitorService fileMonitorService;
#SneakyThrows
#GetMapping("/restart")
public String restartFileMonitoring(){
fileMonitorService.startMonitoring();
return "File monitoring restarted started successfully";
}
}
My app starts on port 8080 and no exception at all. But when I get call this end point localhost:8080/xml/restart
It is not reachable. If I comment out the #PostConstruct then I can call the end point. I am confused how to use this annotation properly. What is wrong in my code?
Update info:-
:: Spring Boot :: (v2.5.4)
2021-09-14 18:23:21.521 INFO 71192 --- [ main] c.f.i.task.BatchProcessorApplication : Starting BatchProcessorApplication using Java 14.0.2 on dev with PID 71192 (/home/dev/Desktop/batch-processor/batch-processor/target/classes started by dev in /home/dev/Desktop/batch-processor/batch-processor)
2021-09-14 18:23:21.523 INFO 71192 --- [ main] c.f.i.task.BatchProcessorApplication : No active profile set, falling back to default profiles: default
2021-09-14 18:23:22.485 INFO 71192 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http)
2021-09-14 18:23:22.495 INFO 71192 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2021-09-14 18:23:22.495 INFO 71192 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/9.0.52]
2021-09-14 18:23:22.564 INFO 71192 --- [ main] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2021-09-14 18:23:22.564 INFO 71192 --- [ main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 988 ms
File to monitor: /home/dev/Desktop/batch-processor/batch-processor/data/in
2021-09-14 18:23:22.647 INFO 71192 --- [ main] c.f.i.task.config.FileMonitorConfig : MONITORING_DIR: /home/dev/Desktop/batch-processor/batch-processor/data/in/
2021-09-14 18:23:22.667 INFO 71192 --- [ main] c.f.i.task.service.FileMonitorService : START_MONITORING
That is the log when I run the app. After debugging I found that while ((key = watchService.take()) != null) { call never returns until I copy some XML file as this app process xml files. Then I copy any xml file in the monitoring dir. I was expecting that #Async it will run in back ground thread in async mode. How to monitory this dir in background thread? So the caller of this method won't be blocked.

PostContstruct semantics
The PostConstruct annotation is part of JSR 330 (Dependency Injection) and is not a Spring custom annotation.
The annotation specification dictates that the annotated method MUST run before the service being injected into context or translated into a service.
Spring supports the PostConstruct lifecycle hook allowing to perform extra post-initialization actions once a bean has been initialized, i.e., it had all its dependencies injected.
Async semantics
The Async annotation on the other hand is a Spring specific annotation allowing to mark a method or a type as being a candidate for asynchronous execution.
Alternative
In a case where you are interested into starting a background process as long as you application starts, you should better use the application lifecycle events and more specifically the ApplicationReadyEvent to spin your monitoring activity:
#Slf4j
#Service
#AllArgsConstructor
public class FileMonitorService {
private final AppProperties appProperties;
private final WatchService watchService;
private final RestTemplate restTemplate;
#EventListener(ApplicationReadyEvent.class)
#Async
public void startMonitoring() {
// ...
}
}
And don't forget to add the #EnableAsync annotation on your Spring Boot configuration type to activate the asynchronous processing feature.

For your case, you don't need to use #PostConstruct and that is why its working when removing the #PostConstruct
to simplify, #PostConstruct is considered as a class empty constructor but it make sure all the Beans are loaded before being called

How to implement ApplicationRunner before springboot application starts?

By reading Spring-boot docs I have understood that I can create a class implementing ApplicationRunner or CommandLineRunner in order to execute code before application starts.
From docs:
An ApplicationReadyEvent is sent after any application and command-line runners have been called. It indicates that the application is ready to service requests.
However, I have following class:
#Component
public class MyClass implements ApplicationRunner {
#Override
public void run(ApplicationArguments args) throws Exception {
Thread.sleep(10000);
}
}
And instead of waiting those 10 seconds to start, it says application started in 3seconds:
2018-11-19 08:51:21.906 INFO 24872 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2018-11-19 08:51:21.909 INFO 24872 --- [ main] com.mycompany.Application : Started Application in 3.565 seconds (JVM running for 4.016)
I assume my class is running in another thread. But I have the feeling that this does not guarantee that my code has finished executing before any possible incoming request.
Is this the correct approach? Am I missing something?

Running a Spring Boot app with Quartz

I have this Spring Boot app. using Quartz (a richly featured, open source job scheduling library that can be integrated within virtually any Java application ) to execute a Job the 10th day of the month
#EnableScheduling
#SpringBootApplication
public class IberiaUtilsApplication implements CommandLineRunner {
public static void main(String[] args) {
SpringApplication app = new SpringApplication(IberiaUtilsApplication.class);
app.run(args);
}
#Override
public void run(String... args) throws Exception {
..
}
}
and inside the config package:
#Configuration
public class JobConfig {
#Bean
public JobDetail sampleJobDetail() {
return JobBuilder.newJob(MonthlyIberiaMetrics.class).withIdentity("iberiaJob")
.usingJobData("iberiaMetrics", "fleet").storeDurably().build();
}
#Bean
public Trigger sampleJobTrigger() {
return newTrigger()
.forJob(sampleJobDetail())
.withIdentity("iberiaTrigger")
.withSchedule(cronSchedule("0 0 10 10 * ?"))
.build();
}
}
I run the app. from the command line, using mvn spring-boot:run but it seems that the Quartz is not initialised:
...
017-10-31 15:11 [main] INFO com.zaxxer.hikari.HikariDataSource - HikariPool-1 - Starting...
2017-10-31 15:11 [main] WARN c.z.hikari.util.DriverDataSource - Registered driver with driverClassName=oracle.jdbc.driver.OracleDriver was not found, trying direct instantiation.
2017-10-31 15:12 [main] INFO com.zaxxer.hikari.HikariDataSource - HikariPool-1 - Start completed.
2017-10-31 15:12 [main] INFO org.quartz.impl.StdSchedulerFactory - Using default implementation for ThreadExecutor
2017-10-31 15:12 [main] INFO o.quartz.core.SchedulerSignalerImpl - Initialized Scheduler Signaller of type: class org.quartz.core.SchedulerSignalerImpl
2017-10-31 15:12 [main] INFO org.quartz.core.QuartzScheduler - Quartz Scheduler v.2.3.0 created.
2017-10-31 15:12 [main] INFO org.quartz.simpl.RAMJobStore - RAMJobStore initialized.
2017-10-31 15:12 [main] INFO org.quartz.core.QuartzScheduler - Scheduler meta-data: Quartz Scheduler (v2.3.0) 'quartzScheduler' with instanceId 'NON_CLUSTERED'
Scheduler class: 'org.quartz.core.QuartzScheduler' - running locally.
NOT STARTED.
Currently in standby mode.
Number of jobs executed: 0
Using thread pool 'org.quartz.simpl.SimpleThreadPool' - with 10 threads.
Using job-store 'org.quartz.simpl.RAMJobStore' - which does not support persistence. and is not clustered.
2017-10-31 15:12 [main] INFO org.quartz.impl.StdSchedulerFactory - Quartz scheduler 'quartzScheduler' initialized from an externally provided properties instance.
2017-10-31 15:12 [main] INFO org.quartz.impl.StdSchedulerFactory - Quartz scheduler version: 2.3.0
2017-10-31 15:12 [main] INFO org.quartz.core.QuartzScheduler - JobFactory set to: org.springframework.boot.autoconfigure.quartz.AutowireCapableBeanJobFactory#64ea8964
2017-10-31 15:12 [main] INFO o.s.j.e.a.AnnotationMBeanExporter - Registering beans for JMX exposure on startup
2017-10-31 15:12 [main] INFO o.s.j.e.a.AnnotationMBeanExporter - Bean with name 'dataSource' has been autodetected for JMX exposure
2017-10-31 15:12 [main] INFO o.s.j.e.a.AnnotationMBeanExporter - Located MBean 'dataSource': registering with JMX server as MBean [com.zaxxer.hikari:name=dataSource,type=HikariDataSource]
2017-10-31 15:12 [main] INFO o.s.c.s.DefaultLifecycleProcessor - Starting beans in phase 2147483647
2017-10-31 15:12 [main] INFO o.s.s.quartz.SchedulerFactoryBean - Starting Quartz Scheduler now
2017-10-31 15:12 [main] INFO org.quartz.core.QuartzScheduler - Scheduler quartzScheduler_$_NON_CLUSTERED started.
2017-10-31 15:12 [Thread-3] INFO o.s.c.a.AnnotationConfigApplicationContext - Closing org.springframework.context.annotation.AnnotationConfigApplicationContext#589ebb: startup date [Tue Oct 31 15:11:56 CET 2017]; root of context hierarchy
2017-10-31 15:12 [Thread-3] INFO o.s.c.s.DefaultLifecycleProcessor - Stopping beans in phase 2147483647
2017-10-31 15:12 [Thread-3] INFO org.quartz.core.QuartzScheduler - Scheduler quartzScheduler_$_NON_CLUSTERED paused.
2017-10-31 15:12 [Thread-3] INFO o.s.s.quartz.SchedulerFactoryBean - Shutting down Quartz Scheduler
2017-10-31 15:12 [Thread-3] INFO org.quartz.core.QuartzScheduler - Scheduler quartzScheduler_$_NON_CLUSTERED shutting down.
2017-10-31 15:12 [Thread-3] INFO org.quartz.core.QuartzScheduler - Scheduler quartzScheduler_$_NON_CLUSTERED paused.
2017-10-31 15:12 [Thread-3] INFO org.quartz.core.QuartzScheduler - Scheduler quartzScheduler_$_NON_CLUSTERED shutdown complete.
2017-10-31 15:12 [Thread-3] INFO o.s.j.e.a.AnnotationMBeanExporter - Unregistering JMX-exposed beans on shutdown
2017-10-31 15:12 [Thread-3] INFO o.s.j.e.a.AnnotationMBeanExporter - Unregistering JMX-exposed beans
2017-10-31 15:12 [Thread-3] INFO com.zaxxer.hikari.HikariDataSource - HikariPool-1 - Shutdown initiated...
2017-10-31 15:12 [Thread-3] INFO com.zaxxer.hikari.HikariDataSource - HikariPool-1 - Shutdown completed.
MacBook-Pro-de-lopes:iberiaUtils lopes$
I also tried changing the expression to 0 * * * * ? (every minute) with the same result
and also created this other class with the same result:
public class ScheduledTasks1 {
private static final SimpleDateFormat dateFormat = new SimpleDateFormat("HH:mm:ss");
#Scheduled(cron = "0 * * * * ?")
public void reportCurrentTime() {
System.out.println("The time is now {}" +
dateFormat.format(new Date()));
}
}
for your information, I have another similar application without Quartz properties and its working fine:
#SpringBootApplication
public class IberiaReservationsApplication {
public static void main(String[] args) {
SpringApplication.run(IberiaReservationsApplication.class, args);
}
#Bean
public JobDetail sampleJobDetail() {
return JobBuilder.newJob(CheckDBJobExecution.class).withIdentity("sampleJob")
.usingJobData("name", "World").storeDurably().build();
}
#Bean
public Trigger sampleJobTrigger() {
return newTrigger()
.forJob(sampleJobDetail())
.withIdentity("sampleTrigger")
.withSchedule(cronSchedule("0 0/2 8-17 * * ?"))
.build();
}
}

Have you considered using Springs own scheduler, it's easy to configure and I've always found it to work well.
https://spring.io/guides/gs/scheduling-tasks/

You are missing various configuration for Quartz here like
Quartz properties
SchedulerFactoryBean
Follow below examples for complete implementation:
https://chynten.wordpress.com/2016/06/17/quartz-with-databse-and-spring-4/
http://www.baeldung.com/spring-quartz-schedule

Apache Camel Cron Job scheduling

New to Apache camel, I have a requirement that I need to look for a folder and move the files from source to destination every five minutes. I wrote the below code, but when I run the Job it is copying the files to destination irrespective of time when I copy the files to source, Please help me in understanding this :
import org.apache.camel.CamelContext;
import org.apache.camel.builder.RouteBuilder;
import org.apache.camel.impl.DefaultCamelContext;
import org.apache.camel.routepolicy.quartz.CronScheduledRoutePolicy;
public class App1 {
public static void main(final String[] arguments) {
final CamelContext camelContext = new DefaultCamelContext();
try {
camelContext.addRoutes(new RouteBuilder() {
#Override
public void configure() throws Exception {
CronScheduledRoutePolicy startPolicy = new CronScheduledRoutePolicy();
startPolicy.setRouteStartTime("0 0/5 * 1/1 * ? *");
from("file:E:\\TestingWatch1\\input")
.routeId("testRoute").routePolicy(startPolicy)
.to("file:E:\\TestingWatch1\\output");
}
});
camelContext.start();
Thread.sleep(10000);
//camelContext.stop();
} catch (Exception camelException) {
}
}
}

In order to schedule a route I have been using the CAMEL QUARTZ component. I believe Claus has been alluding to this option as well:
from("quartz://scheduler_name?cron={{cron.schedule}}")
.routeId("cron-scheduler")
cron.schedule value is set in params as:
00+00+*/2+1/1+*+?+*
I.e to run every two hours.
So to run every 5 minutes that would be something like:
00+*/5+*+1/1+*+?+*

As Claus Ibsen said, you can use cron directly:
public class CopyTest {
public static void main(final String[] arguments) {
final CamelContext camelContext = new DefaultCamelContext();
try {
camelContext.addRoutes(new RouteBuilder() {
#Override
public void configure() throws Exception {
from("file://c:/test/input?scheduler=quartz2&scheduler.cron=00+*/5+*+1/1+*+?+*")
.routeId("testRoute")
.log(LoggingLevel.INFO, "File name : ${header.CamelFileName}")
.to("file://c:/test/output");
}
});
camelContext.start();
Thread.sleep(10*60*1000);
//camelContext.stop();
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
More info can be found here:
http://www.davsclaus.com/2013/08/apache-camel-212-even-easier-cron.html
or here:
http://camel.apache.org/file2.html URI options->Consumer->scheduler
or here:
http://camel.apache.org/quartz2.html Using QuartzScheduledPollConsumerScheduler
Here is my log:
2016-12-23 21:52:24,440 [main ] INFO DefaultCamelContext - Apache Camel 2.15.2 (CamelContext: camel-1) is starting
2016-12-23 21:52:24,440 [main ] INFO ManagedManagementStrategy - JMX is enabled
2016-12-23 21:52:25,329 [main ] INFO DefaultTypeConverter - Loaded 200 type converters
2016-12-23 21:52:25,985 [main ] INFO DefaultCamelContext - AllowUseOriginalMessage is enabled. If access to the original message is not needed, then its recommended to turn this option off as it may improve performance.
2016-12-23 21:52:25,985 [main ] INFO DefaultCamelContext - StreamCaching is not in use. If using streams then its recommended to enable stream caching. See more details at http://camel.apache.org/stream-caching.html
2016-12-23 21:52:26,187 [main ] INFO QuartzComponent - Create and initializing scheduler.
2016-12-23 21:52:26,187 [main ] INFO QuartzComponent - Setting org.quartz.scheduler.jmx.export=true to ensure QuartzScheduler(s) will be enlisted in JMX.
2016-12-23 21:52:26,312 [main ] INFO StdSchedulerFactory - Using default implementation for ThreadExecutor
2016-12-23 21:52:26,312 [main ] INFO SimpleThreadPool - Job execution threads will use class loader of thread: main
2016-12-23 21:52:26,359 [main ] INFO SchedulerSignalerImpl - Initialized Scheduler Signaller of type: class org.quartz.core.SchedulerSignalerImpl
2016-12-23 21:52:26,359 [main ] INFO QuartzScheduler - Quartz Scheduler v.2.2.1 created.
2016-12-23 21:52:26,390 [main ] INFO RAMJobStore - RAMJobStore initialized.
2016-12-23 21:52:26,421 [main ] INFO QuartzScheduler - Scheduler meta-data: Quartz Scheduler (v2.2.1) 'DefaultQuartzScheduler-camel-1' with instanceId 'NON_CLUSTERED'
Scheduler class: 'org.quartz.core.QuartzScheduler' - running locally.
NOT STARTED.
Currently in standby mode.
Number of jobs executed: 0
Using thread pool 'org.quartz.simpl.SimpleThreadPool' - with 10 threads.
Using job-store 'org.quartz.simpl.RAMJobStore' - which does not support persistence. and is not clustered.
2016-12-23 21:52:26,421 [main ] INFO StdSchedulerFactory - Quartz scheduler 'DefaultQuartzScheduler-camel-1' initialized from an externally provided properties instance.
2016-12-23 21:52:26,421 [main ] INFO StdSchedulerFactory - Quartz scheduler version: 2.2.1
2016-12-23 21:52:26,999 [main ] INFO DefaultCamelContext - Route: testRoute started and consuming from: Endpoint[file://c:/test/input?scheduler=quartz2&scheduler.cron=00+*%2F5+*+1%2F1+*+%3F+*]
2016-12-23 21:52:26,999 [main ] INFO QuartzComponent - Starting scheduler.
2016-12-23 21:52:26,999 [main ] INFO QuartzScheduler - Scheduler DefaultQuartzScheduler-camel-1_$_NON_CLUSTERED started.
2016-12-23 21:52:26,999 [main ] INFO DefaultCamelContext - Total 1 routes, of which 1 is started.
2016-12-23 21:52:26,999 [main ] INFO DefaultCamelContext - Apache Camel 2.15.2 (CamelContext: camel-1) started in 2.574 seconds
2016-12-23 21:55:00,052 [amel-1_Worker-1] INFO testRoute - File name : client.log
You'll need the dependency:
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-quartz2</artifactId>
<version>${camel.version}</version>
</dependency>

How to make sure quartz.properties is being used?

I set following properties in my quartz.properties file:
org.quartz.threadPool.threadCount = 60
org.quartz.scheduler.batchTriggerAcquisitionMaxCount = 60
, however, for some reason, apparently it doesn't take effect. because when I start my application, the log shows that it still uses 1 thread in the pool:
[main] INFO org.quartz.impl.StdSchedulerFactory - Using default implementation for ThreadExecutor
[main] INFO org.quartz.core.SchedulerSignalerImpl - Initialized Scheduler Signaller of type: class org.quartz.core.SchedulerSignalerImpl
[main] INFO org.quartz.core.QuartzScheduler - Quartz Scheduler v.2.1.1 created.
[main] INFO org.quartz.simpl.RAMJobStore - RAMJobStore initialized.
[main] INFO org.quartz.core.QuartzScheduler - Scheduler meta-data: Quartz Scheduler (v2.1.1) 'QuartzScheduler' with instanceId 'NON_CLUSTERED' Scheduler class: 'org.quartz.core.QuartzScheduler' - running locally. NOT STARTED. Currently in standby mode. Number of jobs executed: 0
Using **thread pool 'org.quartz.simpl.SimpleThreadPool' - with 1 threads.**
I know, the quartz.properties needs to be at class path to be found. and I just did it.
any other reason why this file is not detected? or it is detected but number of threads is not set correctly?
Thanks

For those who are using Spring + Quartz and quartz.properties file is not working (i.e. gets ignored while starting the application):
Quartz Scheduler (org.quartz.Scheduler) instantiated by Spring Factory Bean (org.springframework.scheduling.quartz.SchedulerFactoryBean) won't read quartz.properties file from the classpath by default as it's said in Quartz docs - you need to set the reference manually:
[in case of Java config]:
#Bean
public SchedulerFactoryBean schedulerFactoryBean() {
SchedulerFactoryBean schedulerFactoryBean = new SchedulerFactoryBean();
schedulerFactoryBean.setConfigLocation(new ClassPathResource("quartz.properties"));
// ...
}
[in case of XML config]:
<bean class="org.springframework.scheduling.quartz.SchedulerFactoryBean">
<property name="configLocation" value="classpath:quartz.properties" />
// ...
</bean>

oops, I found the problem, actually the code was overriding the properties file config by creating an instance of Properties class in the code. so the answer is this line:
sf = new StdSchedulerFactory("conf/quartz.properties");

If someone still looking for answer, they can use the below snippet
#Bean
public SchedulerFactoryBean schedulerFactoryBean() throws IOException {
SchedulerFactoryBean scheduler = new SchedulerFactoryBean();
scheduler.setTriggers(jobOneTrigger());
scheduler.setQuartzProperties(quartzProperties());
scheduler.setJobDetails(jobOneDetail());
return scheduler;
}
#Bean
public Properties quartzProperties() throws IOException {
PropertiesFactoryBean propertiesFactoryBean = new PropertiesFactoryBean();
propertiesFactoryBean.setLocation(new ClassPathResource("/quartz.properties"));
propertiesFactoryBean.afterPropertiesSet();
return propertiesFactoryBean.getObject();
}