SpringBoot中默認緩存實現(xiàn)方案的示例代碼

更新時間：2020年08月13日 17:25:55 作者：qfchenjunbo

這篇文章主要介紹了SpringBoot中默認緩存實現(xiàn)方案,本文通過示例代碼給大家介紹的非常詳細，對大家的學(xué)習(xí)或工作具有一定的參考借鑒價值，需要的朋友可以參考下

在上一節(jié)中，我?guī)Т蠹覍W(xué)習(xí)了詳解SpringBoot集成Redis來實現(xiàn)緩存技術(shù)方案，尤其是結(jié)合Spring Cache的注解的實現(xiàn)方案，接下來在本章節(jié)中，我?guī)Т蠹彝ㄟ^代碼來實現(xiàn)。

一. Spring Boot實現(xiàn)默認緩存

1. 創(chuàng)建web項目

我們按照之前的經(jīng)驗，創(chuàng)建一個web程序，并將之改造成Spring Boot項目，具體過程略。

2. 添加依賴包

<dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
 
<dependency>
 <groupId>mysql</groupId>
 <artifactId>mysql-connector-java</artifactId>
</dependency>
 
<dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-cache</artifactId>
</dependency>

3. 創(chuàng)建application.yml配置文件

server:
 port: 8080
spring:
 application:
 name: cache-demo
 datasource:
 driver-class-name: com.mysql.cj.jdbc.Driver
 username: root
 password: syc
 url: jdbc:mysql://localhost:3306/spring-security?useUnicode=true&characterEncoding=utf8&characterSetResults=utf8&useSSL=false&serverTimezone=UTC
 #cache:
 #type: generic #由redis進行緩存,一共有10種緩存方案
 jpa:
 database: mysql
 show-sql: true #開發(fā)階段,打印要執(zhí)行的sql語句.
 hibernate:
 ddl-auto: update

4. 創(chuàng)建一個緩存配置類

主要是在該類上添加@EnableCaching注解，開啟緩存功能。

package com.yyg.boot.config;
 
import org.springframework.cache.annotation.EnableCaching;
 
/**
 * @Author 一一哥Sun
 * @Date Created in 2020/4/14
 * @Description Description
 * EnableCaching啟用緩存
 */ 
@Configuration
@EnableCaching
public class CacheConfig {
}

5. 創(chuàng)建User實體類

package com.yyg.boot.domain;
 
import lombok.Data;
import lombok.ToString;
 
import javax.persistence.*;
import java.io.Serializable;
 
@Entity
@Table(name="user")
@Data
@ToString
public class User implements Serializable {
 
 //IllegalArgumentException: DefaultSerializer requires a Serializable payload
 // but received an object of type [com.syc.redis.domain.User]
 
 @Id
 @GeneratedValue(strategy = GenerationType.AUTO)
 private Long id;
 
 @Column
 private String username;
 
 @Column
 private String password;
 
}

6. 創(chuàng)建User倉庫類

package com.yyg.boot.repository;
 
import com.yyg.boot.domain.User;
import org.springframework.data.jpa.repository.JpaRepository;
 
public interface UserRepository extends JpaRepository<User,Long> {
}

7. 創(chuàng)建Service服務(wù)類

定義UserService接口

package com.yyg.boot.service;
 
import com.yyg.boot.domain.User;
 
public interface UserService {
 
 User findById(Long id);
 
 User save(User user);
 
 void deleteById(Long id);
 
}

實現(xiàn)UserServiceImpl類

package com.yyg.boot.service.impl;
 
import com.yyg.boot.domain.User;
import com.yyg.boot.repository.UserRepository;
import com.yyg.boot.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.CacheEvict;
import org.springframework.cache.annotation.CachePut;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.stereotype.Service;
 
@Service
public class UserServiceImpl implements UserService {
 
 @Autowired
 private UserRepository userRepository;
 
 //普通的緩存+數(shù)據(jù)庫查詢代碼實現(xiàn)邏輯:
 //User user=RedisUtil.get(key);
 // if(user==null){
 // user=userDao.findById(id);
 // //redis的key="product_item_"+id
 // RedisUtil.set(key,user);
 // }
 // return user;
 
 /**
 * 注解@Cacheable:查詢的時候才使用該注解!
 * 注意:在Cacheable注解中支持EL表達式
 * redis緩存的key=user_1/2/3....
 * redis的緩存雪崩,緩存穿透,緩存預(yù)熱,緩存更新...
 * condition = "#result ne null",條件表達式,當(dāng)滿足某個條件的時候才進行緩存
 * unless = "#result eq null":當(dāng)user對象為空的時候,不進行緩存
 */
 @Cacheable(value = "user", key = "#id", unless = "#result eq null")
 @Override
 public User findById(Long id) {
 
 return userRepository.findById(id).orElse(null);
 }
 
 /**
 * 注解@CachePut:一般用在添加和修改方法中
 * 既往數(shù)據(jù)庫中添加一個新的對象,于此同時也往redis緩存中添加一個對應(yīng)的緩存.
 * 這樣可以達到緩存預(yù)熱的目的.
 */
 @CachePut(value = "user", key = "#result.id", unless = "#result eq null")
 @Override
 public User save(User user) {
 return userRepository.save(user);
 }
 
 /**
 * CacheEvict:一般用在刪除方法中
 */
 @CacheEvict(value = "user", key = "#id")
 @Override
 public void deleteById(Long id) {
 userRepository.deleteById(id);
 }
 
}

8. 創(chuàng)建Controller接口方法

package com.yyg.boot.web;
 
import com.yyg.boot.domain.User;
import com.yyg.boot.service.UserService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
 
@RestController
@RequestMapping("/user")
@Slf4j
public class UserController {
 
 @Autowired
 private UserService userService;
 
 @PostMapping
 public User saveUser(@RequestBody User user) {
 return userService.save(user);
 }
 
 @GetMapping("/{id}")
 public ResponseEntity<User> getUserById(@PathVariable("id") Long id) {
 User user = userService.findById(id);
 log.warn("user="+user.hashCode());
 HttpStatus status = user == null ? HttpStatus.NOT_FOUND : HttpStatus.OK;
 return new ResponseEntity<>(user, status);
 }
 
 @DeleteMapping("/{id}")
 public String removeUser(@PathVariable("id") Long id) {
 userService.deleteById(id);
 return "ok";
 }
 
}

9. 創(chuàng)建入口類

package com.yyg.boot;
 
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
 
@SpringBootApplication
public class CacheApplication {
 
 public static void main(String[] args) {
 SpringApplication.run(CacheApplication.class, args);
 }
 
}

10. 完整項目結(jié)構(gòu)