How to Configure Cache in Spring Boot Applications
In this tutorial we are going to learn about configuring the Cache in Spring Boot Applications with an example.
Caching helps to increase the performance of the application by reducing number of round trips between the database or any expensive resources. In real time we will face the scenarios like we have to execute heavy database query and lets say the data in the database will change very rarely, for this kind of scenarios its not a good idea to hit the database for every call, rather just cache the result at the first time when it hits the database and return the same data again for the other calls.
Steps to configure cache in spring boot applications..
- In pom.xml add spring cache dependency spring-boot-starter-cache module.
- @EnableChaching annotation in the main class at class level helps the spring boot application enable cache mechanism.
- A method level annotation i.e., # @Cacheable is addded to the method for which we want to result to be cached.
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/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.bj</groupId>
<artifactId>SpringBootCache</artifactId>
<version>0.0.1-SNAPSHOT</version>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.6.RELEASE</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-cache</artifactId>
</dependency>
</dependencies>
<properties>
<java.version>1.8</java.version>
</properties>
</project>SpringBootApp.java
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cache.annotation.EnableCaching;
@SpringBootApplication
@EnableCaching
public class SpringBootApp {
public static void main(String[] args) {
SpringApplication.run(SpringBootApp.class, args);
}
}SpringJavaController.java
import java.util.Arrays;
import java.util.List;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import com.bj.model.Customer;
@RestController
public class SpringJavaController {
@RequestMapping("/get-cust-info")
@Cacheable(value="cacheCustInfo")
public List customerInformation() {
System.out.println("I am from customerInformation");
List custDetails = Arrays.asList(
/*
* Here you can add your database logic/flow to get the customer details
* For time being I am hard coding 2 values
*/
new Customer(100,"Bank Of America","USA"),
new Customer(101,"Bank Of India","India")
);
return custDetails;
}
}Customer.java
package com.bj.model;
public class Customer {
private int custNo;
private String name;
private String country;
public Customer() {
}
public Customer(int custNumber, String name, String country) {
this.custNo = custNumber;
this.name = name;
this.country = country;
}
public int getCustNo() {
return custNo;
}
public void setCustNo(int custNo) {
this.custNo = custNo;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getCountry() {
return country;
}
public void setCountry(String country) {
this.country = country;
}
}Output:
Run the application at..
I hit/refreshed the above URL several times and still its showing one system out message means the cached method executing once and storing its data in the cache with key name cacheCustInfo, and it returns the data from cache when we make the same API call again.
Note: Spring doesnt have the ability to clean the cached data automatically so we need to clean it since it is available in the cache memory after our work is done. To manage the cached memory better we can use EhCache, Redis etc providers as an integration into the spring boot application to get the control over the cached data.
Ref. https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-caching.html
Clear the Cache
Generally from our side we will clean or flush the cache after any update or delete operations, for that we use @CacheEvict annotation on the required method.
@CacheEvict(value = "cacheCustInfo", allEntries=true) // @CacheEvict will clear the cached data when we delete any customer info from the database.
public void removeEmployee(Id customerId) {
//Database logic will go here to remove the particular customer from the DB.
}How to Disable cache
If we would like to disable the cache, no need to remove all the annotations just add the below line in the application.properties file, it takes care everything for you.
spring.cache.type=none
