SpringBoot中默认缓存实现方案的示例代码_Java

在上一节中，我带大家学习了详解springboot集成redis来实现缓存技术方案，尤其是结合spring cache的注解的实现方案，接下来在本章节中，我带大家通过代码来实现。

一. spring boot实现默认缓存

1. 创建web项目

我们按照之前的经验，创建一个web程序，并将之改造成spring boot项目，具体过程略。

2. 添加依赖包

<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. 创建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进行缓存,一共有10种缓存方案
 jpa:
 database: mysql
 show-sql: true #开发阶段,打印要执行的sql语句.
 hibernate:
 ddl-auto: update

4. 创建一个缓存配置类

主要是在该类上添加@enablecaching注解，开启缓存功能。

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启用缓存
 */ 
@configuration
@enablecaching
public class cacheconfig {
}

5. 创建user实体类

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. 创建user仓库类

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. 创建service服务类

定义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);
 
}

实现userserviceimpl类

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;
 
 //普通的缓存+数据库查询代码实现逻辑:
 //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:查询的时候才使用该注解!
 * 注意:在cacheable注解中支持el表达式
 * redis缓存的key=user_1/2/3....
 * redis的缓存雪崩,缓存穿透,缓存预热,缓存更新...
 * condition = "#result ne null",条件表达式,当满足某个条件的时候才进行缓存
 * unless = "#result eq null":当user对象为空的时候,不进行缓存
 */
 @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
 * 既往数据库中添加一个新的对象,于此同时也往redis缓存中添加一个对应的缓存.
 * 这样可以达到缓存预热的目的.
 */
 @cacheput(value = "user", key = "#result.id", unless = "#result eq null")
 @override
 public user save(user user) {
 return userrepository.save(user);
 }
 
 /**
 * cacheevict:一般用在删除方法中
 */
 @cacheevict(value = "user", key = "#id")
 @override
 public void deletebyid(long id) {
 userrepository.deletebyid(id);
 }
 
}

8. 创建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. 创建入口类

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. 完整项目结构