<!-- springBoot JPA的起步依赖 -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
</dependency>

#DB Configuration
spring:
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=utf8
    username: root
    password: root
    type: com.alibaba.druid.pool.DruidDataSource
  jpa:
    database: mysql
    show-sql: true
    generate-ddl: false
    hibernate:
      ddl-auto: update

package xyz.ytfs.entity;

import javax.persistence.*;

/**
 * @author by 雨听风说
 * @Classname User
 * @Description TODO(用户的JavaBean)
 * @Date 2020/5/13 17:09
 */

@Entity
@Table(name = "user")
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;
    /*
    @Column属性：当数据库的列明与实体类的属性名一致的时候可以不用配置
     */
    @Column(name = "username")
    private String username;

    @Column(name = "password")
    private String password;

    @Column(name = "name")
    private String name;

   //此处省略setter和getter方法... ...
}

package xyz.ytfs.test;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import xyz.ytfs.SpringBootJpaApplication;
import xyz.ytfs.repository.UserRepository;

/**
 * @author by 雨听风说
 * @Classname JpaTest
 * @Description TODO(JPA的测试)
 * @Date 2020/5/13 17:18
 */

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

    @Autowired
    private UserRepository userRepository;

     @Test
     public void testFindALl() {
        this.userRepository.findAll().forEach(System.out::println);
     }


}

<!-- 配置redis 的启动器 -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>

#DB Configuration
spring:
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=utf8
    username: root
    password: root
    type: com.alibaba.druid.pool.DruidDataSource
  jpa:
    database: mysql
    show-sql: true
    generate-ddl: false
    hibernate:
      ddl-auto: update
      #redis
  redis:
    port: 6399
    host: 127.0.0.1

package xyz.ytfs.test;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.junit.Test;
import org.junit.platform.commons.util.StringUtils;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.test.context.junit4.SpringRunner;
import xyz.ytfs.SpringBootJpaApplication;
import xyz.ytfs.entity.User;
import xyz.ytfs.repository.UserRepository;

import java.util.List;

/**
 * @author by 雨听风说
 * @Classname RedisTest
 * @Description TODO(Redis 测试)
 * @Date 2020/5/13 20:55
 */

@RunWith(SpringRunner.class)
@SpringBootTest(classes = SpringBootJpaApplication.class)
public class RedisTest {
    /*
    泛型代表的是key-value的类型
     */
    @Autowired
    private RedisTemplate<String, String> redisTemplate;

    @Autowired
    private UserRepository repository;

    /*
    jackson的序列化工具，springBoot自动集成redis
     */
    private static final ObjectMapper MAPPER = new ObjectMapper();
    
     @Test
     public void test() throws JsonProcessingException {

        //1.从Redis中获取数据  数据格式json字符串
         String usersJson = this.redisTemplate.boundValueOps("user.findAll").get();

         //2.判断redis中书否存在这个数据
         if (StringUtils.isBlank(usersJson)){

             //3.不存在：数据库查询
             List<User> users = this.repository.findAll();

             //将查询出的数据存储到redis缓存中,先将users集合转换成json格式字符串  使用jackson进行转换
             usersJson = MAPPER.writeValueAsString(users);

             //存储在redis中
             this.redisTemplate.boundValueOps("user.findAll").set(usersJson);
             System.out.println("---------------------------------------");
             System.out.println("\"从数据库中查询数据\" = " + "从数据库中查询数据");

         }else {

             System.out.println("\"从redis中获取数据\" = " + "从redis中获取数据");
         }

         //4.存在：直接返回（测试直接在控制台打印）
         System.out.println("usersJson = " + usersJson);


     }
    
}