mysql - 实体管理器超时

Question

我正在使用 Spring Data，但对于自定义查询，我想开始使用 EntityManager。问题是除了使用 EntityManager 的查询之外，所有使用 Spring Data 的查询都工作正常。 EntityManager 查询一直出现超时错误。

@Bean
public BasicDataSource dataSource() {
    BasicDataSource ds = new BasicDataSource();
    ds.setDriverClassName("com.mysql.jdbc.Driver");
    ds.setUrl(MessageFormat.format(Constants.DATABASE_CONNECTION_URL, host, port, schema));
    ds.setUsername(username);
    ds.setPassword(password);
    ds.setTestWhileIdle(true);
    ds.setValidationQuery(validationQuery);
    ds.setTimeBetweenEvictionRunsMillis(validationTestInterval);
    return ds;
}

@Bean
public EntityManager entityManager() {
    return entityManagerFactory(dataSource()).createEntityManager();
}

@Bean
public EntityManagerFactory entityManagerFactory(BasicDataSource dataSource) {
    HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
    vendorAdapter.setGenerateDdl(true);
    vendorAdapter.setShowSql(false);
    vendorAdapter.setDatabasePlatform("org.hibernate.dialect.MySQL5InnoDBDialect");
    vendorAdapter.setDatabase(Database.MYSQL);

    LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean();
    factory.setJpaVendorAdapter(vendorAdapter);
    factory.setPackagesToScan(
            "com.xxx"
    );

    Properties properties = new Properties();
    properties.setProperty("hibernate.connection.provider_class", "org.hibernate.connection.C3P0ConnectionProvider");
    properties.setProperty("hibernate.connection.driver_class", "com.mysql.jdbc.Driver");
    properties.setProperty("hibernate.connection.url", MessageFormat.format(Constants.DATABASE_CONNECTION_URL, host, port, schema));
    properties.setProperty("hibernate.connection.username", username);
    properties.setProperty("hibernate.connection.password", password);
    properties.setProperty("hibernate.c3p0.acquire_increment", "5");
    properties.setProperty("hibernate.c3p0.idle_test_period", "300");
    properties.setProperty("hibernate.c3p0.min_size", "5");
    properties.setProperty("hibernate.c3p0.timeout", "1000");

    factory.setJpaProperties(properties);
    factory.afterPropertiesSet();

    return factory.getObject();
}

@Bean
public JpaTransactionManager transactionManager(EntityManagerFactory entityManagerFactory) {
    JpaTransactionManager txManager = new JpaTransactionManager();
    JpaDialect jpaDialect = new HibernateJpaDialect();
    txManager.setEntityManagerFactory(entityManagerFactory);
    txManager.setJpaDialect(jpaDialect);
    txManager.setDefaultTimeout(60000);
    txManager.setRollbackOnCommitFailure(true);
    return txManager;
}



@Component
public class ReportGenerator {

    @Autowired
    private EntityManager entityManager;

    private List<MyObject> doSomething() {
        StringBuilder sql = new StringBuilder();
        // build query
        List<MyObject> list = entityManager.createNativeQuery(sql.toString(), MyObject.class).getResultList();
        entityManager.clear();
        return list;
    }

有什么建议吗？

更新 1:

validationQuery = SELECT 1;
validationTestInterval = 30000

Answer 1

@PersistenceContext

@PersistenceContext
private EntityManager entityManager;

更新:

在我看来:这个简短的回答总比没有好，它可以节省我很多时间

link 1

That's fine, but how do I get an EnityManager? This might actually be the coolest part. Basically you’d just define a DAO exactly the way you would if you weren’t using Spring by adding the @PersistenceContext JPA annotation.

link 2 (rus)

2. В бинах, где необходим менеджер сущностей пометить соответствующее поле аннотацией @PersistenceContext

link 3

@PersistenceContext injects a container-managed instance.