10、SpringBoot简单整合SpringDataJPA

创建一个SpringBoot项目

添加依赖

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

    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
        <exclusions>
            <exclusion>
                <groupId>org.junit.vintage</groupId>
                <artifactId>junit-vintage-engine</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
        <scope>test</scope>
    </dependency>
</dependencies>

配置文件

#数据源
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost/test?characterEncoding=utf-8&useSSL=false&serverTimezone=UTC
spring.datasource.username=root
spring.datasource.password=12345
# 后台打印sql语句
spring.jpa.show-sql=true
#实体类结构发生改变时，是否更改表结构
spring.jpa.hibernate.ddl-auto=update

编写实体类并配置实体类与表之间的关系

/**
 * 1.实体类和表的映射关系
 *      @Entity
 *      @Table
 * 2.类中属性和表中字段的映射关系
 *      @Id
 *      @GeneratedValue
 *      @Column
 *      
 * 当属性名满足驼峰命名法时，可以不写@Colum注解     
 */
@Entity
@Table(name="users")
public class Users {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
//    @Column(name = "user_id")
    private Integer userId;
//    @Column(name = "user_name")
    private String userName;
//    @Column(name = "gender")
    private String gender;

    public Integer getUserId() {
        return userId;
    }

    public void setUserId(Integer userId) {
        this.userId = userId;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    @Override
    public String toString() {
        return "Users{" +
                "userId=" + userId +
                ", userName='" + userName + '\'' +
                ", gender='" + gender + '\'' +
                '}';
    }
}

编写Dao接口

import com.example.pojo.Users;
import org.springframework.data.repository.CrudRepository;

public interface UsersDao extends CrudRepository<Users, Integer>{
}

测试

@SpringBootTest
@RunWith(SpringRunner.class)
public class UserDaoTest {
    @Autowired
    private UsersDao usersDao;


    @Test
    public void testSave(){
        Users user = new Users();
        user.setUserName("南海");
        usersDao.save(user);
    }
}