Question

以下行尝试使用JPA Container-Managed JPA2.0 EntityManager从数据库表“Sourcing”中检索所有行，但是它不返回任何结果，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（汇总）：

@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);
    }
}

控制台上的hibernate.show_sql输出从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以前插入和提交的行：

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，任何想法为什么createQuery（“来自Sourcing”）。getResultList（）都不会返回结果，即使：

从MySQL命令行运行“select * from Sourcing”返回2结果
将原始SQL输出从Hibernate复制并粘贴到MySQL命令行中也会返回2个结果
MySQL日志显示已插入行并将其提交到数据库

奇怪的事似乎在这里发生了！我应该在哪里看下一个？交易，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;
}
}

UPDATE（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：

我使用JPA Criteria查询（下面）而不是.createQuery（“来自Sourcing”）尝试“select * from Sourcing”查询以查看它是否有所作为，但它没有解决问题（仍然没有结果返回）

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

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语句继续，以便后续查询查看这些行。因此，在我的EJB Message-Driven-Bean（可能是一个Session bean）的末尾有一个while循环，它阻止bean完全执行，因此提交到数据库。我不需要在任何bean中设置任何per-methods Transactional值，并且可以愉快地嵌套它们，并为同一事务使用多个EntityManagers（在Container Managed Transaction环境中）

JPA EntityManager createQuery不返回任何结果

1 个答案: