spring boot对缓存支持非常灵活，我们可以使用默认的EhCache，也可以整合第三方的框架，只需配置即可。SpringBoot工程使用Redis缓存，也是非常方便（网上许多博文都是自定义RedisTemplate配置来实现，其实就是将SpringMVC的实现方式照搬到了SpringBoot中来，繁琐的同时将SpringBoot的灵活性给丧失掉了），下面代码开始。
- spring boot
- spring data JPA
- Lombok
- H2
- Redis
- Grandle
新建spring boot工程，jdk1.8，具体步骤不做详述，下面是build.grandle：
buildscript {
ext {
springBootVersion = '2.1.1.RELEASE'
}
repositories {
mavenCentral()
}
dependencies {
classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
}
}
apply plugin: 'java'
apply plugin: 'idea'
apply plugin: 'org.springframework.boot'
apply plugin: 'io.spring.dependency-management'
group = 'blob.louie'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = 1.8
targetCompatibility = 1.8
repositories {
maven { url 'http://maven.aliyun.com/nexus/content/groups/public/' }
maven { url 'http://maven.aliyun.com/nexus/content/repositories/jcenter'}
mavenCentral()
}
dependencies {
implementation('org.springframework.boot:spring-boot-starter-cache')
implementation('org.springframework.boot:spring-boot-starter-data-jpa')
implementation('org.springframework.boot:spring-boot-starter-data-redis')
implementation('org.springframework.boot:spring-boot-starter-web')
runtimeOnly('com.h2database:h2')
compileOnly('org.projectlombok:lombok')
testImplementation('org.springframework.boot:spring-boot-starter-test')
}
application.yml中配置H2数据库、Redis连接信息和jpa：
spring:
datasource:
url: jdbc:h2:mem:redis-cache
driver-class-name: org.h2.Driver
redis:
host: localhost
port: 6379
jpa:
database: h2
hibernate:
ddl-auto: create
cache:
type: redis
Application.java类添加@EnableCaching注解开启缓存支持：
@SpringBootApplication
@EnableCaching
public class RedisCacheApplication {
public static void main(String[] args) {
SpringApplication.run(RedisCacheApplication.class, args);
}
}package blob.louie.rediscache.entity;
import lombok.Data;
import org.hibernate.annotations.GenericGenerator;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
import java.io.Serializable;
/**
* user entity
* @author louie
* @date created in 2018-12-3 23:27
*/
@Data
@Entity
@Table(name = "b_user")
public class User implements Serializable {
@Id
@GenericGenerator(name = "uuid", strategy = "uuid")
@GeneratedValue(generator = "uuid")
private String id;
private String name;
private Integer age;
private String mobile;
private String address;
}
@Data为Lombok插件提供的标签，需IDE支持（IDEA一定要设置Enable annotation processing），否则会报编译错误；
@Table、@Id均为JPA相关标签，对spring data JPA不了解的亲，只需理解这是实现ORM的方式即可；
特别说明：实体类要序列化，否则在作为接口参数时无法获取；
package blob.louie.rediscache.service.impl;
import blob.louie.rediscache.dao.UserRepository;
import blob.louie.rediscache.entity.User;
import blob.louie.rediscache.service.UserService;
import org.springframework.cache.annotation.CacheEvict;
import org.springframework.cache.annotation.CachePut;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.stereotype.Service;
/**
* user service implement
* @author louie
* @date created in 2018-12-3 23:33
*/
@Service
public class UserServiceImpl implements UserService {
private final UserRepository userRepository;
public UserServiceImpl (UserRepository userRepository) {
this.userRepository = userRepository;
}
/**
* save use, put redis cache
* @param user user data
* @return saved user data
*/
@Override
@CachePut(value = "user", key = "#result.id", unless = "#result eq null")
public User save(User user) {
return userRepository.save(user);
}
/**
* find user by id,redis cacheable
* @param userId user id
* @return if exist return the user, else return null
*/
@Override
@Cacheable(value = "user", key = "#userId", unless = "#result eq null")
public User findUser(String userId) {
return userRepository.findById(userId).orElse(null);
}
/**
* delete user by id, and remove redis cache
* @param userId user id
*/
@Override
@CacheEvict(value = "user", key = "#userId")
public void deleteUser(String userId) {
userRepository.findById(userId).ifPresent(userRepository::delete);
}
}@CachePut、@Cacheable、@CacheEvict是spring缓存相关标签，其中参数及其含义不做过多说明。
package blob.louie.rediscache.dao;
import blob.louie.rediscache.entity.User;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
/**
* use repository
* @author louie
* @date created in 2018-12-3 23:36
*/
@Repository
public interface UserRepository extends JpaRepository<User, String> {
}JpaRepository为JPA提供的持久层接口，实现了多种常用的数据库操作方法，也支持自定义函数，只需在UserRepository中添加自定义的函数即可；
package blob.louie.rediscache.controller;
import blob.louie.rediscache.entity.User;
import blob.louie.rediscache.service.UserService;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
/**
* user controller
* @author louie
* @date created in 2018-12-3 23:25
*/
@RestController
@RequestMapping(value = "/user")
public class UserController {
private final UserService userService;
public UserController (UserService userService) {
this.userService = userService;
}
@PostMapping
public User saveUser(@RequestBody User user) {
return userService.save(user);
}
@GetMapping(value = "/{userId}")
public ResponseEntity<User> getUser(@PathVariable String userId) {
User user = userService.findUser(userId);
HttpStatus status = user == null ? HttpStatus.NOT_FOUND: HttpStatus.OK;
return new ResponseEntity<>(user, status);
}
@DeleteMapping(value = "/{userId}")
public ResponseEntity deleteUser(@PathVariable String userId) {
userService.deleteUser(userId);
return new ResponseEntity<>(HttpStatus.NO_CONTENT);
}
}执行Application.java类启动服务，使用PostMan进行接口验证：
响应信息为创建成功后的用户数据，id由uuid策略自动生成；
查看redis中的数据，可以看到以cache的value和key组合作为键值的缓存数据：
验证查询是否是从redis缓存中获取，只需在查询的实现处打断点，若调用查询时未进入断点则说明数据来源不是Repository，或者开启JPA的sql输出功能，查看是否有sql输出。
返回状态码204，说明资源已删除；
调用查询api，返回404，资源不存在：
查看Redis数据，缓存已清除：