1、遠程服務(wù)器端要關(guān)閉防火墻

 systemctl stop firewalld.service

或者關(guān)閉后設(shè)置 禁止防火墻開機啟動。

 systemctl disable firewalld.service  

2.關(guān)閉 redis 保護模式，在 redis.conf 文件中

 [root@localhost redis-7.0.7]# vi redis.conf 

修改 protected 為 no，如下：

image.png

注釋掉 redis 的 ip 地址綁定，還是在 redis.conf 中，將 bind:127.0.0.1 注釋掉，如下：

image.png

確認(rèn)了這三步之后，就可以遠程連接 redis 了

pom.xml

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.3.RELEASE</version>
    </parent>
    <dependencies> 
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--熱部署配置-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.0.1</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
            <scope>runtime</scope>
        </dependency>
        <!-- redis相關(guān) -->
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-pool2</artifactId> 
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis</artifactId>
        </dependency>
    </dependencies>
</project>

application.yml

 server:
    port: 8089
    servlet:
        context-path: /elm
spring:
    datasource:
        driver-class-name: com.mysql.jdbc.Driver
        url: jdbc:mysql://localhost:3306/emp?characterEncoding=utf-8&useSSL=false
        username: root
        password: root
    redis:
        database: 0
        host: 遠程ip地址
        port: 6379
logging:
    level:
        org.springframework: debug
        com.xx.dao: debug 
        #能看到控制臺sql語句日志，方便區(qū)分是從緩存中讀數(shù)據(jù)還是訪問mapper都mysql數(shù)據(jù)
mybatis:
   # mapper-locations: classpath:mapper/*.xml
    type-aliases-package: com.xx.boot.po

主啟動類上加@EnableCaching注解啟用緩存

@SpringBootApplication
@EnableCaching
public class HelloApplication {
    public static void main(String[] args) {
        SpringApplication.run(HelloApplication.class, args);
    }
}

實體類 需要實現(xiàn) Serializable 序列化

public class Dept  implements Serializable{ 
    private Integer deptno;
    private String dname;
    private String loc;
    //getter,setter省略
}

mapper層接口

@Mapper
public interface DeptMapper {
    @Select("select * from dept")
    public List<Dept> getDept();

    @Select("select * from dept where deptno = #{deptno}")
    public Dept getDeptById(Integer deptno);

    @Delete("delete from dept where deptno = #{deptno}")
    public Integer delDeptById(Integer deptno);
}

service層接口

public interface DeptService {
    public List<Dept> getDept();
       
    public  Dept  getDeptById(Integer deptno);
     
    public Integer delDeptById(Integer deptno);
}

service層實現(xiàn)類

 @Service
public class DeptServiceImpl implements DeptService {

    @Autowired
    DeptMapper deptMapper;

    @Autowired
    RedisTemplate<Object, Object> redisTemplate;
    
    public List<Dept> getDept() { 
        List<Dept> list = null; 
        ValueOperations<Object, Object> op = redisTemplate.opsForValue();
        if(op.get("user")==null) { 
            list = deptMapper.getDept( );
            op.set("user",  list);
        }else {
            list = (List<Dept>) op.get("user");
            System.out.println(list);
        } 
        return list; 
    }

    @Cacheable(value = "dept",key = "#deptno",unless = "#result==null")
    public Dept getDeptById(Integer deptno) { 
        //可通過控制臺日志查看是否有sql輸出，有就證明讀mysql了，沒有就證明從緩存中讀的
        Dept dept = deptMapper.getDeptById(deptno); 
        return dept;
    }


    @CacheEvict(value = "dept",key = "#deptno")
    public Integer delDeptById(Integer deptno) { 
        return deptMapper.delDeptById(deptno);
    }
 
}

@Cacheable解的作用是將 value = "dept",key = "#deptno" 值作為組合，作為緩存數(shù)據(jù)的鍵值 , #的參數(shù)是將方法參數(shù)deptno取出的意思，每次訪問該方法時，注解會到緩存中檢查是否有value 和 key 值作為組合的鍵值存在，若存在，則不會調(diào)用該方法，也就不會執(zhí)行mapper的方法，否則就會調(diào)用方法，并把返回值存入緩存作為value,key值則是 value = "user",key = "#id"的組合
unless是緩存條件，上例中是結(jié)果不為空時進行緩存

@CacheEvict 注解是刪除功能，當(dāng)訪問該方法時，若存在value = "user",key = "#id" 組合而成的鍵值，就把該緩存數(shù)據(jù)刪除

controller層

@RestController
public class HelloController {
    @Autowired
    DeptService deptService;
    
    @RequestMapping("/getDept")
    public List<Dept> getDept(){           
        return deptService.getDept();
    }
     
    @RequestMapping("/getDeptById")
    public Dept getDeptById(Integer deptno) { 
        return deptService.getDeptById(deptno);
    }
     
    @RequestMapping("/delDeptById")
    public Integer delDeptById(Integer deptno) { 
        return deptService.delDeptById(deptno);
    }
}