我找到的所有示例都包含有关 Hibernate.cfg.xml 的信息，但我使用的是 hibernate.properties 而不是它。
在资源文件夹中：
hibernate.dialet=org.hibernate.dialect.PostgreSQL9Dialect
hibernate.show_sql=true
hibernate.hbm2ddl.auto=update
我在这里使用属性：
@Configuration
@EnableJpaRepositories("com.some.server.repository")
@EnableTransactionManagement
@PropertySource("classpath:db.properties")
@ComponentScan("com.some.server")
public class DataBaseConfig {
@Resource
private Environment env;
@Bean
public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean();
em.setDataSource(dataSource());
em.setPackagesToScan(env.getRequiredProperty("db.entity.package"));
em.setJpaVendorAdapter(new HibernateJpaVendorAdapter());
em.setJpaProperties(getHibernateProperties());
return em;
}
@Bean
public DataSource dataSource() {
BasicDataSource ds = new BasicDataSource();
ds.setUrl(env.getRequiredProperty("db.url"));
ds.setDriverClassName(env.getRequiredProperty("db.driver"));
ds.setUsername(env.getRequiredProperty("db.username"));
ds.setPassword(env.getRequiredProperty("db.password"));
ds.setInitialSize(Integer.valueOf(env.getRequiredProperty("db.initialSize")));
ds.setMinIdle(Integer.valueOf(env.getRequiredProperty("db.minIdle")));
ds.setMaxIdle(Integer.valueOf(env.getRequiredProperty("db.maxIdle")));
ds.setTimeBetweenEvictionRunsMillis(Long.valueOf(env.getRequiredProperty("db.timeBetweenEvictionRunsMillis")));
ds.setMinEvictableIdleTimeMillis(Long.valueOf(env.getRequiredProperty("db.minEvictableIdleTimeMillis")));
ds.setTestOnBorrow(Boolean.valueOf(env.getRequiredProperty("db.testOnBorrow")));
ds.setValidationQuery(env.getRequiredProperty("db.validationQuery"));
return ds;
}
@Bean
public PlatformTransactionManager transactionManager() {
JpaTransactionManager manager = new JpaTransactionManager();
manager.setEntityManagerFactory(entityManagerFactory().getObject());
return manager;
}
public Properties getHibernateProperties() {
try {
Properties properties = new Properties();
InputStream is = getClass().getClassLoader().getResourceAsStream("hibernate.properties");
properties.load(is);
return properties;
} catch (IOException e) {
throw new IllegalArgumentException("Can't find 'hibernate.properties' in classpath!", e);
}
}
}
是否有机会使用 hibernate.properties 获得会话（对于 fetch.LAZY）？
更新：
我有 JPA，但仍然需要会话。
在我的实体中，我有：
@Entity
@Table(name = "users")
public class User {
...
@ManyToOne(fetch = FetchType.LAZY, cascade = {CascadeType.MERGE, CascadeType.PERSIST})
@JoinColumn(name = "id_city", nullable = true)
private City city;
public City getCity() {
return city;
}
public void setCity(City city) {
this.city = city;
}
...
}
和：
@Entity
@Table(name = "city")
public class City {
....
@OneToMany(fetch = FetchType.LAZY, mappedBy = "city")
@JsonIgnore
private Set<User> users;
public Set<User> getUsers() {
return users;
}
public void setUsers(Set<User> users) {
this.users = users;
}
...
}
所以，当我试图得到：
@RestController
@RequestMapping("/user")
public class UserController {
@Autowired
private UserRepository userRepository;
@Autowired
private ProfessionRepository profRepository;
@RequestMapping(value = "", method = RequestMethod.GET)
public List<User> getAllUsers() {
// List<User> list = userRepository.findAll();
return userRepository.findAll();
}
From:
public interface UserRepository extends JpaRepository<User, Long>{
}
我有一个错误，如果 id_city 不为空：
如果 id_city 为空（未使用 Fetch.LAZY），则一切正常：
