按条件搜索时PostgreSQL和Spring致命错误

Question

我使用Criteria搜索来自数据库的数据。但经过多次要求，我遇到了问题：

2016-07-14 17:54:08 ERROR o.h.e.jdbc.spi.SqlExceptionHelper - FATAL: sorry, too many clients already

这是我的功能出现错误：

public Page<T> findPageByCriteria(Map<String, Object> criteriaMap, List<String> order, List<String> dir) {
    Integer start = (Integer) criteriaMap.get("start");
    Integer limit = (Integer) criteriaMap.get("limit");

    Criteria criteria = getPageCriteria(criteriaMap, order, dir);

    // Pagination
    List<BaseEntity> elements = null;
    Integer totalCount = null;
    if (start != null && limit != null) {
        totalCount = criteria.list().size();
        criteria.setFirstResult(start);
        criteria.setMaxResults(limit);
        elements = criteria.list();
        ProjectionList projectionList = Projections.projectionList();
        projectionList.add(Projections.rowCount());
        projectionList.add(Projections.groupProperty(order.get(0)));
        criteria.setProjection(projectionList);
        criteria.setFirstResult(0);
        criteria.setMaxResults(Integer.MAX_VALUE);
    }
    else {
        elements = criteria.list();

        totalCount = elements.size();
    }

当我调用此函数时，它将在DB中创建1个连接，但其他功能则不是。我不知道为什么？

你能给我一些建议或建议我一些库来避免出现这个错误吗？

我认为我们在配置文件中增加max_connections是个好主意。我们没有永远增加它。

谢谢;）

更新

这是Hibernate配置：

@Bean
public LocalSessionFactoryBean sessionFactory() throws Exception {
    LocalSessionFactoryBean sessionFactory = new LocalSessionFactoryBean();
    sessionFactory.setDataSource(dataSource);
    sessionFactory.setHibernateProperties(hibernateProperties());
    sessionFactory.setMappingDirectoryLocations(
            new ClassPathResource[] { new ClassPathResource("/.../../...") });

    return sessionFactory;
}

private Properties hibernateProperties() {
    Properties properties = new Properties();
    properties.put(DIALECT, environment.getRequiredProperty(DIALECT));
    properties.put(SHOW_SQL, environment.getRequiredProperty(SHOW_SQL));
    properties.put(FORMAT_SQL, environment.getRequiredProperty(FORMAT_SQL));

    return properties;
}

@Bean
@Primary
@Autowired
public HibernateTransactionManager transactionManager(SessionFactory s) {
    HibernateTransactionManager txManager = new HibernateTransactionManager();
    txManager.setSessionFactory(s);
    return txManager;
}

@Bean
@Autowired
public HibernateTemplate hibernateTemplate(SessionFactory s) {
    HibernateTemplate hibernateTemplate = new HibernateTemplate(s);
    return hibernateTemplate;
}