SpringBoot整合JPA和Redis

5.3.1 添加Spring Data JPA的起步依赖

<dependency>
    <groupId>org.springframework.bootgroupId>
    <artifactId>spring-boot-starter-data-jpaartifactId>
dependency>

5.3.2 添加数据库驱动依赖

<dependency>
    <groupId>mysqlgroupId>
    <artifactId>mysql-connector-javaartifactId>
dependency>

5.3.3 在application.properties中配置数据库和jpa的相关属性

#DB Configuration:
spring.datasource.driverClassName=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/db2?useUnicode=true&characterEncoding=utf8&serverTimezone=GMT%2B8&useSSL=false
spring.datasource.username=root
spring.datasource.password=root

#JPA Configuration:
spring.jpa.database=MySQL
spring.jpa.show-sql=true
spring.jpa.generate-ddl=true
spring.jpa.hibernate.ddl-auto=update
spring.jpa.hibernate.naming_strategy=org.hibernate.cfg.ImprovedNamingStrategy

5.3.4 创建实体配置实体

@Entity
public class User {
    // 主键
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    // 用户名
    private String username;
    // 密码
    private String password;
    // 姓名
    private String name;
 
    //此处省略setter和getter方法... ...
}

5.3.5 编写UserRepository

public interface UserRepository extends JpaRepository<User,Long>{
    public List<User> findAll();
}

5.3.6 编写测试类

@RunWith(SpringRunner.class)
@SpringBootTest(classes=MySpringBootApplication.class)
public class JpaTest {

    @Autowired
    private UserRepository userRepository;

    @Test
    public void test(){
        List<User> users = userRepository.findAll();
        System.out.println(users);
    }

}

注意：如果是jdk9，执行报错如下：

原因：jdk缺少相应的jar

解决方案：手动导入对应的maven坐标，如下：

<dependency>
    <groupId>javax.xml.bindgroupId>
    <artifactId>jaxb-apiartifactId>
    <version>2.3.0version>
dependency>

5.4 SpringBoot整合Redis

5.4.1 添加redis的起步依赖

<dependency>
    <groupId>org.springframework.bootgroupId>
    <artifactId>spring-boot-starter-data-redisartifactId>
dependency>

5.4.2 配置redis的连接信息

#Redis 的配置
spring.redis.host=127.0.0.1
spring.redis.port=6379

5.4.3 注入RedisTemplate测试redis操作

@RunWith(SpringRunner.class)
@SpringBootTest(classes = SpringbootJpaApplication.class)
public class RedisTest {

    @Autowired
    private UserRepository userRepository;

    @Autowired
    private RedisTemplate<String, String> redisTemplate;

    @Test
    public void test() throws JsonProcessingException {
        //从redis缓存中获得指定的数据
        String userListData = redisTemplate.boundValueOps("user.findAll").get();
        //如果redis中没有数据的话
        if(null==userListData){
            //查询数据库获得数据
            List<User> all = userRepository.findAll();
            //转换成json格式字符串
            ObjectMapper om = new ObjectMapper();
            userListData = om.writeValueAsString(all);
            //将数据存储到redis中，下次在查询直接从redis中获得数据，不用在查询数据库
            redisTemplate.boundValueOps("user.findAll").set(userListData);
            System.out.println("===============从数据库获得数据===============");
        }else{
            System.out.println("===============从redis缓存中获得数据===============");
        }

        System.out.println(userListData);

    }

}