1, 引入Maven 或gradle依赖

主要是开启starter-cache 和引入caffeine

dependencies {
    implementation("org.springframework.boot:spring-boot-starter-cache")
    implementation("com.github.ben-manes.caffeine:caffeine:2.8.5")
}

2, 在application class开启

@EnableCaching
@SpringBootApplication
class DemoCacheApplication

3, 写配置类

@Configuration
class AppConfig {
    @Bean
    fun cacheManager(): CacheManager {
        return CaffeineCacheManager("Student")
            .apply {
                isAllowNullValues = false
                setCaffeine(
                    Caffeine.newBuilder()
                        .maximumSize(100)
                        .expireAfterAccess(1, TimeUnit.HOURS)
                )
            }
    }
}

4, 在具体的类上使用caffeine

interface StudentRepository : CrudRepository<Student, Long>
@Service
@CacheConfig(cacheNames = ["Student"])
class StudentService(val studentRepository: StudentRepository) {
    @Cacheable(key = "#id")
    fun findStudentById(id: Long) = studentRepository.findById(id)
    @CacheEvict(key = "#id")
    fun updateStudent(id: Long, student: Student) {
        val existingStudent = this.findStudentById(id).get().copy(name = student.name)
        studentRepository.save(existingStudent)
    }
}

注意@CacheEvict (缓存移除)的用法, 当使用updateStudent 方法后, 会移除对应的id值的缓存, 参考https://www.concretepage.com/spring/cacheevict_spring

5, 其他相关class

@Entity
data class Student(
    @Id
    val id: Long?,
    val name: String
)
@RestController
class StudentController(val studentService: StudentService, val cacheManager: CacheManager) {
    @GetMapping("/{id}")
    fun getStudent(@PathVariable id: Long) = studentService.findStudentById(id)
    @GetMapping("/update/{id}")
    fun updateStudent(@PathVariable id: Long) =
        studentService.updateStudent(id, Student(id, "Name ${UUID.randomUUID()}"))
    @GetMapping("/all")
    fun allCache(): MutableCollection<String> = cacheManager.cacheNames
}

本文参考项目:
https://github.com/lynas/spring-cache-non-reactive
https://www.youtube.com/watch?v=_j9htDP8AhQ