SpringBoot整合Spring Data JPA（+整合redis)

首先进行目录展示：

 

整合Spring Data JPA

添加Spring Data JPA的起步依赖

<dependency>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>

添加数据库驱动依赖

<!-- MySQL连接驱动 -->
<dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
</dependency>

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

#数据库配置信息
spring.datasource.driverClassCame=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/test?serverTimezone=UTC&useUnicode=true&characterEncoding=utf8
spring.datasource.username=root
spring.datasource.password=123456

#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

创建实体配置实体

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String username;
    private String password;
    private String name;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                ", name='" + name + '\'' +
                '}';
    }
}

@Entity标注该类为实体类

编写UserRepository

public interface UserRepository extends JpaRepository<User,Long> {

    public List<User> findAll();
}

 编写测试类

import com.itheima.domain.User;
import com.itheima.repository.UserRepository;
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 java.util.List;

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

    @Autowired
    private UserRepository userRepository;

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

控制台打印信息

注意：如果是jdk9，执行报错，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：

<!--jdk9需要导入如下坐标--> 
<dependency>    
    <groupId>javax.xml.bind</groupId>    
    <artifactId>jaxb-api</artifactId>    
    <version>2.3.0</version> 
</dependency>

整合redis

添加redis的起步依赖：

<!-- 配置使用redis启动器 -->
<dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-data-redis</artifactId>
      <version>1.5.16.RELEASE</version>
</dependency>

配置redis的连接信息

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

注入RedisTemplate测试redis操作

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.itheima.domain.User;
import com.itheima.repository.UserRepository;
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.data.redis.core.RedisTemplate;
import org.springframework.test.context.junit4.SpringRunner;

import java.util.List;

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

    @Autowired
    private RedisTemplate<String,String> redisTemplate;

    @Autowired
    private UserRepository userRepository;

    @Test
    public void test() throws JsonProcessingException {
        //1.从redis中获得数据，数据形式json字符串
        String userListJson = redisTemplate.boundValueOps("user.findAll").get();
        //2.判断redis中是否存在数据
        if (null==userListJson){
            //3.不存在数据，从数据库中查询
            List<User> all = userRepository.findAll();
            //4.将查询出的数据存储到redis缓存中
            //将list集合转换成json格式的字符串，使用jackson进行转换
            ObjectMapper objectMapper = new ObjectMapper();
            userListJson = objectMapper.writeValueAsString(all);
            redisTemplate.boundValueOps("user.findAll").set(userListJson);

            System.out.println("===============从数据库中查询==============");
        }else{
            System.out.println("===============从redis中查询==============");
        }
        //4.将数据在控制台打印
        System.out.println(userListJson);
    }
}

测试前记得打开redis服务器！