Skip to main content

Spring boot application events

Spring boot provides an easy and quick way to implement the event listeners. Spring boot generates multiple events during it's application lifecycle. We will see the below events which are provided by spring application under "org.springframework.boot.context.event" Java package. Thanks to spring that we don't need to focus on writing the listeners but the business logics which we want to execute during a specific event and to do that we just need to annotate our business method with @EventListener.

  • ApplicationContextInitializedEvent

Event published when a SpringApplication is starting up and the ApplicationContext is prepared and ApplicationContextInitializers have been called but before any bean definitions are loaded.

Implementation and code example

  • ApplicationEnvironmentPreparedEvent

Event published when a SpringApplication is starting up and the Environment is first available for inspection and modification.

Implementation and code example

  • ApplicationFailedEvent

Event published by a SpringApplication when it fails to start.

Implementation and code example

  • ApplicationPreparedEvent

Event published as when a SpringApplication is starting up and the ApplicationContext is fully prepared but not refreshed. The bean definitions will be loaded and the Environment is ready for use at this stage.
For implementation you can refer any of the other events defined here, for example:- ApplicationReadyEvent or ApplicationStartedEvent in below sections.

  • ApplicationReadyEvent

Event published as late as conceivably possible to indicate that the application is ready to service requests. The source of the event is the SpringApplication itself, but beware of modifying its internal state since all initialization steps will have been completed by then.

Implementation and code example

  • ApplicationStartedEvent

Event published once the application context has been refreshed but before any application and command line runners have been called.

Implementation and code example

  • ApplicationStartingEvent

Event published as early as conceivably possible as soon as a SpringApplication has been started - before the Environment or ApplicationContext is available, but after the ApplicationListeners have been registered. The source of the event is the SpringApplication itself, but beware of using its internal state too much at this early stage since it might be modified later in the lifecycle.

Implementation and code example





Labels:

Comments

Post a Comment

Popular Posts

Setting up kerberos in Mac OS X

Kerberos in MAC OS X Kerberos authentication allows the computers in same domain network to authenticate certain services with prompting the user for credentials. MAC OS X comes with Heimdal Kerberos which is an alternate implementation of the kerberos and uses LDAP as identity management database. Here we are going to learn how to setup a kerberos on MAC OS X which we will configure latter in our application. Installing Kerberos In MAC we can use Homebrew for installing any software package. Homebrew makes it very easy to install the kerberos by just executing a simple command as given below. brew install krb5 Once installation is complete, we need to set the below export commands in user's profile which will make the kerberos utility commands and compiler available to execute from anywhere. Open user's bash profile: vi ~/.bash_profile Add below lines: export PATH=/usr/local/opt/krb5/bin:$PATH export PATH=/usr/local/opt/krb5/sbin:$PATH export LDFLAGS=&
85 comments
Read more

Why HashMap key should be immutable in java

HashMap is used to store the data in key, value pair where key is unique and value can be store or retrieve using the key. Any class can be a candidate for the map key if it follows below rules. 1. Overrides hashcode() and equals() method.   Map stores the data using hashcode() and equals() method from key. To store a value against a given key, map first calls key's hashcode() and then uses it to calculate the index position in backed array by applying some hashing function. For each index position it has a bucket which is a LinkedList and changed to Node from java 8. Then it will iterate through all the element and will check the equality with key by calling it's equals() method if a match is found, it will update the value with the new value otherwise it will add the new entry with given key and value. In the same way it check for the existing key when get() is called. If it finds a match for given key in the bucket with given hashcode(), it will return the value other
1 comment
Read more

Entity to DTO conversion in Java using Jackson

It's very common to have the DTO class for a given entity in any application. When persisting data, we use entity objects and when we need to provide the data to end user/application we use DTO class. Due to this we may need to have similar properties on DTO class as we have in our Entity class and to share the data we populate DTO objects using entity objects. To do this we may need to call getter on entity and then setter on DTO for the same data which increases number of code line. Also if number of DTOs are high then we need to write lot of code to just get and set the values or vice-versa. To overcome this problem we are going to use Jackson API and will see how to do it with minimal code only. Maven dependency <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-databind</artifactId> <version>2.9.9</version> </dependency> Entity class Below is
Post a Comment
Read more

Multiple data source with Spring boot, batch and cloud task

Here we will see how we can configure different datasource for application and batch. By default, Spring batch stores the job details and execution details in database. If separate data source is not configured for spring batch then it will use the available data source in your application if configured and create batch related tables there. Which may be the unwanted burden on application database and we would like to configure separate database for spring batch. To overcome this situation we will configure the different datasource for spring batch using in-memory database, since we don't want to store batch job details permanently. Other thing is the configuration of  spring cloud task in case of multiple datasource and it must point to the same data source which is pointed by spring batch. In below sections, we will se how to configure application, batch and cloud task related data sources. Application Data Source Define the data source in application properties or yml con
47 comments
Read more