Springboot从两个库中的两个表搜索,将两个表的数据用list显示出来

可以通过使用Spring Data JPA来实现从两个库中的两个表搜索，并将两个表的数据用list显示出来。下面是一个简单的实现示例：

1. 在application.properties文件中配置两个数据源：

spring.datasource.first.url=jdbc:mysql://localhost:3306/first_db
spring.datasource.first.username=root
spring.datasource.first.password=123456

spring.datasource.second.url=jdbc:mysql://localhost:3306/second_db
spring.datasource.second.username=root
spring.datasource.second.password=123456

2. 创建两个数据源的JPA配置文件：

@Configuration
@EnableJpaRepositories(
    basePackages = "com.example.first.repository",
    entityManagerFactoryRef = "firstEntityManagerFactory",
    transactionManagerRef = "firstTransactionManager"
)
public class FirstDbConfig {
 
    @Primary
    @Bean(name = "firstDataSource")
    @ConfigurationProperties(prefix = "spring.datasource.first")
    public DataSource dataSource() {
        return DataSourceBuilder.create().build();
    }
 
    @Primary
    @Bean(name = "firstEntityManagerFactory")
    public LocalContainerEntityManagerFactoryBean entityManagerFactory(EntityManagerFactoryBuilder builder,
                                                                        @Qualifier("firstDataSource") DataSource dataSource) {
        return builder
                .dataSource(dataSource)
                .packages("com.example.first.entity")
                .persistenceUnit("first")
                .build();
    }
 
    @Primary
    @Bean(name = "firstTransactionManager")
    public PlatformTransactionManager transactionManager(
            @Qualifier("firstEntityManagerFactory") EntityManagerFactory entityManagerFactory) {
        return new JpaTransactionManager(entityManagerFactory);
    }
}

@Configuration
@EnableJpaRepositories(
    basePackages = "com.example.second.repository",
    entityManagerFactoryRef = "secondEntityManagerFactory",
    transactionManagerRef = "secondTransactionManager"
)
public class SecondDbConfig {
 
    @Bean(name = "secondDataSource")
    @ConfigurationProperties(prefix = "spring.datasource.second")
    public DataSource dataSource() {
        return DataSourceBuilder.create().build();
    }
 
    @Bean(name = "secondEntityManagerFactory")
    public LocalContainerEntityManagerFactoryBean entityManagerFactory(EntityManagerFactoryBuilder builder,
                                                                        @Qualifier("secondDataSource") DataSource dataSource) {
        return builder
                .dataSource(dataSource)
                .packages("com.example.second.entity")
                .persistenceUnit("second")
                .build();
    }
 
    @Bean(name = "secondTransactionManager")
    public PlatformTransactionManager transactionManager(
            @Qualifier("secondEntityManagerFactory") EntityManagerFactory entityManagerFactory) {
        return new JpaTransactionManager(entityManagerFactory);
    }
}

3. 创建两个实体类和两个repository类：

@Entity
@Table(name = "first_table")
public class FirstEntity {
 
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
 
    private String name;
 
    // getter and setter
}

public interface FirstRepository extends JpaRepository<FirstEntity, Long> {
 
    List<FirstEntity> findByName(String name);
}

@Entity
@Table(name = "second_table")
public class SecondEntity {
 
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
 
    private String name;
 
    // getter and setter
}

public interface SecondRepository extends JpaRepository<SecondEntity, Long> {
 
    List<SecondEntity> findByName(String name);
}

4. 创建一个service类，用于从两个库中的两个表搜索，并将两个表的数据用list显示出来：

@Service
public class DataService {
 
    @Autowired
    private FirstRepository firstRepository;
 
    @Autowired
    private SecondRepository secondRepository;
 
    public List<Object> search(String name) {
        List<Object> result = new ArrayList<>();
        result.addAll(firstRepository.findByName(name));
        result.addAll(secondRepository.findByName(name));
        return result;
    }
}

5. 创建一个controller类，用于接收请求并调用service类进行搜索：

@RestController
public class DataController {
 
    @Autowired
    private DataService dataService;
 
    @GetMapping("/search")
    public List<Object> search(@RequestParam String name) {
        return dataService.search(name);
    }
}

这样，当你访问/search?name=xxx时，就可以从两个库中的两个表中搜索，并将结果以list的形式返回了。