JPA EntityManager createQuery 没有返回结果

Question

以下行尝试使用 JPA 容器管理的 JPA2.0 EntityManager 从数据库表“Sourcing”中检索所有行，但是它没有返回任何结果，即使表中似乎有 2 行：

em.createQuery("from Sourcing").getResultList();

我正在使用 JBoss 6.0 、JVM 1.6、MySQL 5.5.10 和 Hibernate 3.6.3

最初持久化 Sourcing 对象的类是（总结）：

@Stateless
@Local
public final class MyBean implements MyBeanLocal {

    @PersistenceContext
    private EntityManager em;

    public MyBean() {}

    public void methodA() {
        methodB();
    }

    private void methodB() {
        methodC();
    }

    private void methodC() {
        Sourcing sourcing = new Sourcing( … values ...);
        em.persist(sourcing);
    }
}

hibernate.show_sql 上的输出控制台从 Hibernate 的角度显示 SQL 语句（发送到 MySQL）

select sourcing0_.sourcingId as sourcingId7_, sourcing0_.foundResults as foundRes2_7_, sourcing0_.numberOfAdults as numberOf3_7_, sourcing0_.numberofchildren as numberof4_7_, sourcing0_.numberofinfants as numberof5_7_, sourcing0_.numberofseniors as numberof6_7_, sourcing0_.scopeBeginDateTime as scopeBeg7_7_, sourcing0_.scopeEndDateTime as scopeEnd8_7_, sourcing0_.searchId as searchId7_, sourcing0_.searchDateTime as searchDa9_7_, sourcing0_.serviceId as serviceId7_, sourcing0_.sourceId as sourceId7_, sourcing0_.sourcingFinishDateTime as sourcin10_7_, sourcing0_.sourcingStartedDateTime as sourcin11_7_, sourcing0_.timeStamp as timeStamp7_, sourcing0_.version as version7_ from sourcing sourcing0_

MySQL 日志文件的以下输出显示之前插入并提交了行：

223 Query   insert into sourcing (foundResults, numberOfAdults, numberofchildren, numberofinfants, numberofseniors, scopeBeginDateTime, scopeEndDateTime, searchId, searchDateTime, serviceId, sourceId, sourcingFinishDateTime, sourcingStartedDateTime, timeStamp, version) values (0, 1, 0, 0, 0, null, null, 1, '2011-08-15 00:00:00', 372, 2, null, '2011-07-18 15:47:00', null, 0)
223 Query   insert into sourcing (foundResults, numberOfAdults, numberofchildren, numberofinfants, numberofseniors, scopeBeginDateTime, scopeEndDateTime, searchId, searchDateTime, serviceId, sourceId, sourcingFinishDateTime, sourcingStartedDateTime, timeStamp, version) values (0, 1, 0, 0, 0, null, null, 1, '2011-08-15 00:00:00', 530, 2, null, '2011-07-18 15:47:00', null, 0)
224 Connect user@localhost on mydatabase
224 Query   /* mysql-connector-java-5.1.15 ( Revision: ${bzr.revision-id} ) */SHOW VARIABLES WHERE Variable_name ='language' OR Variable_name = 'net_write_timeout' OR Variable_name = 'interactive_timeout' OR Variable_name = 'wait_timeout' OR Variable_name = 'character_set_client' OR Variable_name = 'character_set_connection' OR Variable_name = 'character_set' OR Variable_name = 'character_set_server' OR Variable_name = 'tx_isolation' OR Variable_name = 'transaction_isolation' OR Variable_name = 'character_set_results' OR Variable_name = 'timezone' OR Variable_name = 'time_zone' OR Variable_name = 'system_time_zone' OR Variable_name = 'lower_case_table_names' OR Variable_name = 'max_allowed_packet' OR Variable_name = 'net_buffer_length' OR Variable_name = 'sql_mode' OR Variable_name = 'query_cache_type' OR Variable_name = 'query_cache_size' OR Variable_name = 'init_connect'
224 Query   /* mysql-connector-java-5.1.15 ( Revision: ${bzr.revision-id} ) */SELECT @@session.auto_increment_increment
224 Query   SHOW COLLATION
224 Query   SET NAMES latin1
224 Query   SET character_set_results = NULL
224 Query   SET autocommit=1
224 Query   SET sql_mode='STRICT_TRANS_TABLES'
224 Query   SELECT @@session.tx_isolation
224 Query   SET autocommit=0
.....
223 Query   commit
224 Query   select sourcing0_.sourcingId as sourcingId7_, sourcing0_.foundResults as foundRes2_7_, sourcing0_.numberOfAdults as numberOf3_7_, sourcing0_.numberofchildren as numberof4_7_, sourcing0_.numberofinfants as numberof5_7_, sourcing0_.numberofseniors as numberof6_7_, sourcing0_.scopeBeginDateTime as scopeBeg7_7_, sourcing0_.scopeEndDateTime as scopeEnd8_7_, sourcing0_.searchId as searchId7_, sourcing0_.searchDateTime as searchDa9_7_, sourcing0_.serviceId as serviceId7_, sourcing0_.sourceId as sourceId7_, sourcing0_.sourcingFinishDateTime as sourcin10_7_, sourcing0_.sourcingStartedDateTime as sourcin11_7_, sourcing0_.timeStamp as timeStamp7_, sourcing0_.version as version7_ from sourcing sourcing0_

总之，知道为什么 createQuery("from Sourcing").getResultList()不返回任何结果，即使：

1. 从 MySQL 命令行运行“select * from Sourcing”会返回 2 个结果
2. 将原始 SQL 输出从 Hibernate 复制并粘贴到 MySQL 命令行也会返回 2 个结果
3. MySQL 日志显示行已被插入和提交给数据库

这里似乎发生了一些奇怪的事情！接下来我该看哪里？事务、缓存？

更新： Entity 类定义如下（删除了一些 getter 和 setter）：

@Entity
@Table(name = "sourcing")
public class Sourcing implements java.io.Serializable, Cloneable {

private static final long serialVersionUID = 1L;
private Integer sourcingId;
private Service service;
private Search search;
private Source source;
private Date searchDateTime;
private Date sourcingStartedDateTime;
private Date sourcingFinishedDateTime;
private Date scopeBeginDateTime;
private Date scopeEndDateTime;
private Integer numberOfAdults;
private Integer numberOfChildren;
private Integer numberOfInfants;
private Integer numberOfSeniors;
private Boolean foundResults;

private int version;
private Date timeStamp;

private boolean isFareMonitoring = false;

private List<Flight> flights = new ArrayList<Flight>(0);
private List<Segment> segments = new ArrayList<Segment>(0);
private List<Fare> fares = new ArrayList<Fare>(0);

public Sourcing() {
}

public Sourcing(Search search, Source source, Service service,
        Date sourcingStartedDateTime,
        Integer numberOfAdults, Integer numberOfChildren,
        Integer numberOfInfants, Integer numberOfSeniors,
        Boolean foundResults) {

    this.search = search;
    this.source = source;
    this.service = service;
    this.sourcingStartedDateTime = sourcingStartedDateTime;
    this.numberOfAdults = numberOfAdults;
    this.numberOfChildren = numberOfChildren;
    this.numberOfInfants = numberOfInfants;
    this.numberOfSeniors = numberOfSeniors;
    this.foundResults = foundResults;

    if (search.isFareMonitoring()) {
        this.isFareMonitoring = true;
    }
}

@Id
@GeneratedValue(strategy = IDENTITY)
@Column(name = "sourcingId", unique = true, nullable = false)
public Integer getSourcingId() {
    return this.sourcingId;
}

public void setSourcingId(Integer sourcingId) {
    this.sourcingId = sourcingId;
}

@Version
@Column(columnDefinition="TINYINT")
public int getVersion() {
    return version;
}

public void setVersion(int version) {
    this.version = version;
}

@Temporal(TemporalType.TIMESTAMP)
@Column(name="timeStamp", columnDefinition="TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP")
public Date getTimeStamp() {
    return timeStamp;
}

public void setTimeStamp(Date timeStamp) {
    this.timeStamp = timeStamp;
}

 // to make 3 days, beginOffSet = -1, endOffSet = 1 [ i.e. -1, 0, 1]
public static void setScope(Sourcing sourcing, int beginOffSet, int endOffSet) {  

    Calendar cal = new GregorianCalendar();
    cal.setTime(sourcing.getSearchDateTime());

    cal.add(Calendar.DAY_OF_MONTH, beginOffSet);
    sourcing.setScopeBeginDateTime(cal.getTime());

    cal.add(Calendar.DAY_OF_MONTH, (-beginOffSet + endOffSet)); // --1 + 1 = 2
    sourcing.setScopeEndDateTime(cal.getTime());
}

@Transient
public final boolean isFareMonitoring() {
    return isFareMonitoring;
}

public final void setFareMonitoring(boolean isFareMonitoring) {
    this.isFareMonitoring = isFareMonitoring;
}
}

---

更新（7 月 20 日）我按照建议启用了 org.hibernate.jdbc 和 org.hibernate.loader TRACE 日志记录。输出如下：

18:25:02,891 DEBUG [com.myproject.beans.ReceiveFareBean] SLEEPING FOR 3 SECONDS ......
18:25:05,890 DEBUG [com.myproject.beans.ReceiveFareBean] AWAKE. 
18:25:05,891 TRACE [org.hibernate.engine.query.QueryPlanCache] located HQL query plan in cache (from Sourcing)
18:25:05,891 TRACE [org.hibernate.engine.query.QueryPlanCache] located HQL query plan in cache (from Sourcing)
18:25:05,891 TRACE [org.hibernate.engine.query.HQLQueryPlan] find: from Sourcing
18:25:05,891 TRACE [org.hibernate.engine.QueryParameters] named parameters: {}
18:25:05,891 DEBUG [org.hibernate.jdbc.AbstractBatcher] about to open PreparedStatement (open PreparedStatements: 0, globally: 0)
18:25:05,891 DEBUG [org.hibernate.jdbc.ConnectionManager] opening JDBC connection
18:25:05,891 DEBUG [org.hibernate.SQL] select sourcing0_.sourcingId as sourcingId7_, sourcing0_.foundResults as foundRes2_7_, sourcing0_.numberOfAdults as numberOf3_7_, sourcing0_.numberofchildren as numberof4_7_, sourcing0_.numberofinfants as numberof5_7_, sourcing0_.numberofseniors as numberof6_7_, sourcing0_.scopeBeginDateTime as scopeBeg7_7_, sourcing0_.scopeEndDateTime as scopeEnd8_7_, sourcing0_.searchId as searchId7_, sourcing0_.searchDateTime as searchDa9_7_, sourcing0_.serviceId as serviceId7_, sourcing0_.sourceId as sourceId7_, sourcing0_.sourcingFinishDateTime as sourcin10_7_, sourcing0_.sourcingStartedDateTime as sourcin11_7_, sourcing0_.timeStamp as timeStamp7_, sourcing0_.version as version7_ from sourcing sourcing0_
18:25:05,892 INFO  [STDOUT] Hibernate: select sourcing0_.sourcingId as sourcingId7_, sourcing0_.foundResults as foundRes2_7_, sourcing0_.numberOfAdults as numberOf3_7_, sourcing0_.numberofchildren as numberof4_7_, sourcing0_.numberofinfants as numberof5_7_, sourcing0_.numberofseniors as numberof6_7_, sourcing0_.scopeBeginDateTime as scopeBeg7_7_, sourcing0_.scopeEndDateTime as scopeEnd8_7_, sourcing0_.searchId as searchId7_, sourcing0_.searchDateTime as searchDa9_7_, sourcing0_.serviceId as serviceId7_, sourcing0_.sourceId as sourceId7_, sourcing0_.sourcingFinishDateTime as sourcin10_7_, sourcing0_.sourcingStartedDateTime as sourcin11_7_, sourcing0_.timeStamp as timeStamp7_, sourcing0_.version as version7_ from sourcing sourcing0_
18:25:05,892 TRACE [org.hibernate.jdbc.AbstractBatcher] preparing statement
18:25:05,892 TRACE [org.hibernate.loader.Loader] Bound [1] parameters total
18:25:05,892 DEBUG [org.hibernate.jdbc.AbstractBatcher] about to open ResultSet (open ResultSets: 0, globally: 0)
18:25:05,893 TRACE [org.hibernate.loader.Loader] processing result set
18:25:05,893 TRACE [org.hibernate.loader.Loader] done processing result set (0 rows)
18:25:05,893 DEBUG [org.hibernate.jdbc.AbstractBatcher] about to close ResultSet (open ResultSets: 1, globally: 1)
18:25:05,893 DEBUG [org.hibernate.jdbc.AbstractBatcher] about to close PreparedStatement (open PreparedStatements: 1, globally: 1)
18:25:05,893 TRACE [org.hibernate.jdbc.AbstractBatcher] closing statement
18:25:05,893 DEBUG [org.hibernate.jdbc.ConnectionManager] aggressively releasing JDBC connection
18:25:05,893 DEBUG [org.hibernate.jdbc.ConnectionManager] releasing JDBC connection [ (open PreparedStatements: 0, globally: 0) (open ResultSets: 0, globally: 0)]
18:25:05,893 TRACE [org.hibernate.loader.Loader] total objects hydrated: 0
18:25:05,893 DEBUG [org.hibernate.engine.StatefulPersistenceContext] initializing non-lazy collections
18:25:05,893 DEBUG [com.myproject.beans.ReceiveFareBean] NUMBER OF SOURCINGS CURRENTLY IN THE DATABASE = 0
18:25:05,893 DEBUG [com.myproject.beans.ReceiveFareBean] SLEEPING FOR 3 SECONDS ......

---

7 月 21 日更新：

我尝试使用 JPA Criteria 查询（如下）而不是 .createQuery("from Sourcing") 进行“select * from Sourcing”查询，以查看它是否有所不同，但它没有解决问题（仍然没有返回结果）

CriteriaBuilder criteriaBuilder = em.getCriteriaBuilder();
CriteriaQuery<Sourcing> criteriaQuery = criteriaBuilder.createQuery(Sourcing.class);
Root<Sourcing> sourcing = criteriaQuery.from(Sourcing.class);
criteriaQuery.select(sourcing);
TypedQuery<Sourcing> typedQuery = em.createQuery(criteriaQuery);
List<Sourcing> sourcings = typedQuery.getResultList();

Answer 1

已解决：
在 EJB bean 完全执行之前，数据库中的行不可用于其他事务（即 EntityManager.merge()），因此允许事务 COMMIT 到数据库。通过使用 MySQL 日志记录，我注意到 Hibernate 发出了语句“SET AUTOCOMMIT=0”，这将导致插入/更新等由 COMMIT 语句进行，以便后续查询能够查看这些行。
因此，在我的 EJB 消息驱动 Bean（可能是会话 Bean）末尾有一个 while 循环，该循环阻止该 Bean 完全执行，从而阻止该 Bean 提交到数据库。我不需要在任何 bean 内设置任何方法的事务值，并且它们可以愉快地嵌套，并为同一事务使用多个 EntityManager（在容器管理事务环境中）