以前一直使用的都是mybatis（mybatis-plus）框架操作数据库。前一端时间有个朋友问了一下JPA查询统计后结果集不是一个实体该怎么接收处理的问题？
首先创建maven项目引入下面依赖：pom.xml
4.0.0
org.springframework.boot
spring-boot-starter-parent
2.0.5.RELEASE
study-5-domain
org.springframework.boot
spring-boot-starter-web
org.springframework.boot
spring-boot-starter-data-jpa
mysql
mysql-connector-java
runtime
org.springframework.boot
spring-boot-configuration-processor
true
org.springframework.boot
spring-boot-devtools
true
org.springframework.boot
spring-boot-starter-test
test
org.projectlombok
lombok
provided
org.springframework.boot
spring-boot-maven-plugin
创建配置文件application.yml。示例：
spring:
datasource:
jdbc-url: jdbc:mysql://127.0.0.1:3306/db_comm_01?useUnicode=true&characterEncoding=utf-8&useSSL=false
username: root
password: Root1234
driver-class-name: com.mysql.jdbc.Driver
member:
datasource:
jdbc-url: jdbc:mysql://127.0.0.1:3306/db_member_01?useUnicode=true&characterEncoding=utf-8&useSSL=false
username: root
password: Root1234
driver-class-name: com.mysql.jdbc.Driver
jpa:
database-platform: org.hibernate.dialect.MySQL5Dialect
show-sql: true
hibernate:
#不自动创建表。
ddl-auto: none
多数据源配置。
DataSourseConfig.java注入数据源
/**
* 数据源配置
* @Author Bertram.Wang
* @Date 2019年3月30日
*/
@Configuration
public class DataSourceConfig {
@Bean("dsComm")
@Primary
@ConfigurationProperties(prefix = "spring.datasource")
public DataSource dataSource(){
return DataSourceBuilder.create().build();
}
@Bean("dsMember")
@ConfigurationProperties(prefix = "spring.member.datasource")
public DataSource dataSourceSlave(){
return DataSourceBuilder.create().build();
}
}
多个数据源只需要分开设置entityManager， transactionManager即可。分别创建CommDataSourceConfig.java,
@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
entityManagerFactoryRef = "entityManagerFactoryComm",//配置连接工厂 entityManagerFactory
transactionManagerRef = "transactionManagerComm", //配置 事物管理器 transactionManager
basePackages = {"bertram.springcloud.study.repository.comm"}
)
@SuppressWarnings({"rawtypes", "unchecked"})
public class CommDataSourceConfig {
@Autowired
@Qualifier("dsComm")
private DataSource dataSourceMaster;
@Autowired
private JpaProperties jpaProperties;
@Bean("entityManagerComm")
@Primary
public EntityManager entityManagerComm(EntityManagerFactoryBuilder builder) {
return entityManagerFactoryComm(builder).getObject().createEntityManager();
}
@Bean("entityManagerFactoryComm")
@Primary
public LocalContainerEntityManagerFactoryBean entityManagerFactoryComm(EntityManagerFactoryBuilder builder) {
return builder.dataSource(dataSourceMaster)
.properties(getVendorProperties())
.packages("bertram.springcloud.study.entity.comm")
.persistenceUnit("commPersistenceUnit")
.build();
}
private Map getVendorProperties() {
HibernateSettings hibernateSettings = new HibernateSettings();
return jpaProperties.getHibernateProperties(hibernateSettings);
}
@Bean("transactionManagerComm")
@Primary
public PlatformTransactionManager transactionManagerComm(EntityManagerFactoryBuilder builder) {
return new JpaTransactionManager(entityManagerFactoryComm(builder).getObject());
}
}
MemberDataSourceConfig.java
@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
entityManagerFactoryRef = "entityManagerFactoryMember",//配置连接工厂 entityManagerFactory
transactionManagerRef = "transactionManagerMember", //配置 事物管理器 transactionManager
basePackages = {"bertram.springcloud.study.repository.member"}
)
@SuppressWarnings({"rawtypes", "unchecked"})
public class MemberDataSourceConfig {
@Autowired
@Qualifier("dsMember")
private DataSource dataSource;
@Autowired
private JpaProperties jpaProperties;
@Bean("entityManagerFactoryMember")
public LocalContainerEntityManagerFactoryBean entityManagerFactoryMember(EntityManagerFactoryBuilder builder) {
return builder.dataSource(dataSource)
.properties(getVendorProperties())
.packages("bertram.springcloud.study.entity.member")
.build();
}
@Bean("entityManagerMember")
public EntityManager entityManager(EntityManagerFactoryBuilder builder) {
return entityManagerFactoryMember(builder).getObject().createEntityManager();
}
@Bean("transactionManagerMember")
public PlatformTransactionManager transactionManager(EntityManagerFactoryBuilder builder) {
return new JpaTransactionManager(entityManagerFactoryMember(builder).getObject());
}
private Map getVendorProperties() {
HibernateSettings hibernateSettings = new HibernateSettings();
return jpaProperties.getHibernateProperties(hibernateSettings);
}
}
即可。
对应的repository写在对应的包下面就能分别识别数据源了。
具体文档结构
repository示例：
@Repository
public interface UserRepository extends JpaRepository {
User findOneById(Integer id);
}
@Repository
public interface MemberRepository extends JpaRepository {
Member findOneById(Integer id);
}
实体类
@Data
@AllArgsConstructor
@NoArgsConstructor
@ToString
@EqualsAndHashCode(callSuper=false)
@Entity
@Table(name="sys_user")
public class User implements Serializable {
private static final long serialVersionUID = -7643897007130979275L;
@Id
private Integer id;
private Date createDate;
private Date modifyDate;
private String name;
private String password;
}
@Data
@NoArgsConstructor
@AllArgsConstructor
@ToString
@EqualsAndHashCode(callSuper=false)
@Entity
@Table(name="member")
public class Member implements Serializable {
private static final long serialVersionUID = -42305693425865718L;
@Id
private Integer id;
private Date createDate;
private Date modifyDate;
private String name;
private String phone;
private String password;
}
数据库表：
数据库表
测试：
@RunWith(SpringRunner.class)
@SpringBootTest(classes={Application.class})// 指定启动类
public class ApplicationTest {
private static final Logger log = LoggerFactory.getLogger(ApplicationTest.class);
@Autowired
UserRepository userRepository;
@Autowired
MemberRepository memberRepository;
@Test
public void test() {
User user = userRepository.findOneById(1);
Member member = memberRepository.findOneById(1);
log.info("user:{}", user);
log.info("member:{}", member);
}
}
执行结果：
执行日志
当我们查询的结果集和实体无对应的时候。
1：直接创建map接收。
示例：
@Query(value="SELECT u.id AS user_id, u.name AS user_name, u.password AS user_password, r.id AS role_id, r.name AS role_name FROM sys_user u LEFT JOIN sys_user_role ur ON ur.user_id = u.id LEFT JOIN sys_role r ON ur.role_id = r.id WHERE u.id = ?1", nativeQuery=true)
Map findOneByUserId(Integer userId);
2：创建一个vo类接收：
示例：
@Data
@NoArgsConstructor
@AllArgsConstructor
@Entity
public class UserRoleTest {
@Id
private Integer userId;
private String userName;
private String userPassword;
private Integer roleId;
private String roleName;
}
@Repository
public interface UserRoleTestRepository extends JpaRepository {
@Query(value="SELECT u.id AS user_id, u.name AS user_name, u.password AS user_password, r.id AS role_id, r.name AS role_name FROM sys_user u LEFT JOIN sys_user_role ur ON ur.user_id = u.id LEFT JOIN sys_role r ON ur.role_id = r.id WHERE u.id = ?1", nativeQuery=true)
UserRoleTest findOneByUserId(Integer userId);
}
测试：
@Test
public void userRoleTest() throws Exception {
UserRoleTest userRoleTest = userRoleTestRepository.findOneByUserId(1);
Map map = userRepository.findOneByUserId(1);
log.info("userRoleTest:{}", userRoleTest);
log.info("map:{}",new ObjectMapper().writeValueAsString(map));
}
执行结果：
测试结果
注： 后者使用一定要关闭自动生成表功能,否则会生成表格user_role_test.