Example method of using ehcache three steps to get springboot cache

This article mainly introduces the data caching function of Spring Boot application based on Ehcache 3.0. In the Spring Boot application, we can quickly handle data caching with Spring Caching. Next, we'll show you how to get the Spring Boot cache done in 3 steps.

1. Create an Spring Boot project and add an Maven dependency

The maven dependency file of the Spring Boot application you create should look at least like the following:

<?xml version="1.0" encoding="UTF-8"?>
<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>
 <parent>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-parent</artifactId>
 <version>2.1.3.RELEASE</version>
 <relativePath/> <!-- lookup parent from repository -->
 </parent>
 <groupId>com.ramostear</groupId>
 <artifactId>cache</artifactId>
 <version>0.0.1-SNAPSHOT</version>
 <name>cache</name>
 <description>Demo project for Spring Boot</description>

 <properties>
 <java.version>1.8</java.version>
 </properties>

 <dependencies>
 <dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-cache</artifactId>
 </dependency>
 <dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-web</artifactId>
 </dependency>
 <dependency>
  <groupId>org.ehcache</groupId>
  <artifactId>ehcache</artifactId>
 </dependency>
 <dependency>
  <groupId>javax.cache</groupId>
  <artifactId>cache-api</artifactId>
 </dependency>
 <dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-test</artifactId>
  <scope>test</scope>
 </dependency>
 <dependency>
  <groupId>org.projectlombok</groupId>
  <artifactId>lombok</artifactId>
 </dependency>
 </dependencies>

 <build>
 <plugins>
  <plugin>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-maven-plugin</artifactId>
  </plugin>
 </plugins>
 </build>

</project>

Dependency description:

spring-boot-starter-cache provides caching support for Spring Boot applications ehcache provides a cache implementation of Ehcache cache-api provides a cache specification based on JSR-107

2. Configure the Ehcache cache

Now, you need to tell Spring Boot where to find the cache configuration file, which needs to be set in the Spring Boot configuration file:

spring.cache.jcache.config=classpath:ehcache.xml

Then use the @ EnableCaching annotation to turn on the Spring Boot application caching function, and you can operate in the main application class:

package com.ramostear.cache;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cache.annotation.EnableCaching;

@SpringBootApplication
@EnableCaching
public class CacheApplication {

 public static void main(String[] args) {
 SpringApplication.run(CacheApplication.class, args);
 }
}

Next, you need to create a configuration file for ehcache, which is placed under the ClassPath, such as the resources directory:

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://www.ehcache.org/v3"
    xmlns:jsr107="http://www.ehcache.org/v3/jsr107"
    xsi:schemaLocation="
      http://www.ehcache.org/v3 http://www.ehcache.org/schema/ehcache-core-3.0.xsd
      http://www.ehcache.org/v3/jsr107 http://www.ehcache.org/schema/ehcache-107-ext-3.0.xsd">
  <service>
    <jsr107:defaults enable-statistics="true"/>
  </service>

  <cache alias="person">
    <key-type>java.lang.Long</key-type>
    <value-type>com.ramostear.cache.entity.Person</value-type>
    <expiry>
      <ttl unit="minutes">1</ttl>
    </expiry>
    <listeners>
      <listener>
        <class>com.ramostear.cache.config.PersonCacheEventLogger</class>
        <event-firing-mode>ASYNCHRONOUS</event-firing-mode>
        <event-ordering-mode>UNORDERED</event-ordering-mode>
        <events-to-fire-on>CREATED</events-to-fire-on>
        <events-to-fire-on>UPDATED</events-to-fire-on>
        <events-to-fire-on>EXPIRED</events-to-fire-on>
        <events-to-fire-on>REMOVED</events-to-fire-on>
        <events-to-fire-on>EVICTED</events-to-fire-on>
      </listener>
    </listeners>
    <resources>
        <heap unit="entries">2000</heap>
        <offheap unit="MB">100</offheap>
    </resources>
  </cache>
</config>

Finally, you need to define a cache event listener to record the system's operation of cached data. The fastest way is to implement CacheEventListener interface:

package com.ramostear.cache.config;

import org.ehcache.event.CacheEvent;
import org.ehcache.event.CacheEventListener;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @author ramostear
 * @create-time 2019/4/7 0007-0:48
 * @modify by :
 * @since:
 */
public class PersonCacheEventLogger implements CacheEventListener<Object,Object>{

  private static final Logger logger = LoggerFactory.getLogger(PersonCacheEventLogger.class);

  @Override
  public void onEvent(CacheEvent cacheEvent) {
    logger.info("person caching event {} {} {} {}",
        cacheEvent.getType(),
        cacheEvent.getKey(),
        cacheEvent.getOldValue(),
        cacheEvent.getNewValue());
  }
}

3. Annotate methods with @ Cacheable annotations

To enable Spring Boot to cache our data, we also need to annotate the business method with the @ Cacheable annotation, telling Spring Boot that the data generated in this method needs to be added to the cache:

package com.ramostear.cache.service;

import com.ramostear.cache.entity.Person;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.stereotype.Service;

/**
 * @author ramostear
 * @create-time 2019/4/7 0007-0:51
 * @modify by :
 * @since:
 */
@Service(value = "personService")
public class PersonService {

  @Cacheable(cacheNames = "person",key = "#id")
  public Person getPerson(Long id){
    Person person = new Person(id,"ramostear","ramostear@163.com");
    return person;
  }
}

Through the above three steps, we have completed the caching function of Spring Boot. Next, we will test the actual situation of cache under 1.

4. Cache testing

To test our application, create a simple Restful endpoint that calls PersonService to return an Person object:

package com.ramostear.cache.controller;

import com.ramostear.cache.entity.Person;
import com.ramostear.cache.service.PersonService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;


/**
 * @author ramostear
 * @create-time 2019/4/7 0007-0:54
 * @modify by :
 * @since:
 */
@RestController
@RequestMapping("/persons")
public class PersonController {

  @Autowired
  private PersonService personService;

  @GetMapping("/{id}")
  public ResponseEntity<Person> person(@PathVariable(value = "id") Long id){
    return new ResponseEntity<>(personService.getPerson(id), HttpStatus.OK);
  }
}

Person is a simple POJO class:

package com.ramostear.cache.entity;
import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;

import java.io.Serializable;

/**
 * @author ramostear
 * @create-time 2019/4/7 0007-0:45
 * @modify by :
 * @since:
 */
@Getter
@Setter
@AllArgsConstructor
@NoArgsConstructor
public class Person implements Serializable{

  private Long id;

  private String username;

  private String email;
}

After all the above preparations are completed, let's compile and run the application. After the project is successfully started, open it in a browser: http://localhost: 8080/persons/1, and you will see the following information in the browser page:

{"id":1,"username":"ramostear","email":"ramostear@163.com"}

At this time, observe the log information output by the console:

2019-04-07 01:08:01.001 INFO 6704 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet : Completed initialization in 5 ms
2019-04-07 01:08:01.054 INFO 6704 --- [e [_default_]-0] c.r.cache.config.PersonCacheEventLogger : person caching event CREATED 1 null com.ramostear.cache.entity.Person@ba8a729

Since we are requesting API for the first time, there is no cached data. Therefore, Ehcache creates a piece of cached data, which can be seen by looking at 1 in CREATED.

We set the cache expiration time to 1 minute (1) in the ehcache. xml file, so we refresh the browser within 1 minute and will not see new log output. After 1 minute, the cache expires and we refresh the browser again and will see the following log output:

2019-04-07 01:09:28.612 INFO 6704 --- [e [_default_]-1] c.r.cache.config.PersonCacheEventLogger : person caching event EXPIRED 1 com.ramostear.cache.entity.Person@a9f3c57 null
2019-04-07 01:09:28.612 INFO 6704 --- [e [_default_]-1] c.r.cache.config.PersonCacheEventLogger : person caching event CREATED 1 null com.ramostear.cache.entity.Person@416900ce

The first log prompt cache has expired, and the second log prompt Ehcache has recreated one cached data.

Concluding remarks

In this case, the implementation of Spring Boot application cache based on Ehcache is explained in three simple steps. The article focuses on the basic steps and methods of caching implementation, simplifying the specific business code. Interested friends can expand themselves, and they can contact me at any time when they encounter problems.