誰能說出為什么此JPA條件查詢在執行時（休眠）會生成無效的SQL語句，以及如何解決它？

Question

我很難構造一個條件查詢來從id = 2的Role實體獲取“ permissions”屬性。permission屬性為Set類型，因此我正在創建一個聯接並從中選擇，但是查詢失敗，語法無效，報告“'where子句'中的未知列'2L'”

生成錯誤的條件查詢是通過以下方式構建的：

EntityManager entityManager = getEntityManager();
CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
CriteriaQuery<Object> criteriaQuery = criteriaBuilder.createQuery();

Class<?> queryScopeClass = temp.pack.commons.user.Role.class;

Root<?> from = criteriaQuery.from(queryScopeClass);

Path<?> idAttrPath = from.get("id");
// also tried criteriaBuilder.equal(attributePath, new Long(2))
Predicate predicate = criteriaBuilder.equal(attributePath, criteriaBuilder.literal(new Long(2)))
criteriaQuery.where(predicate);


Path<?> attributePath = from.get("permissions");
PluralAttributePath<?> pluralAttrPath = (PluralAttributePath<?>)attributePath;
PluralAttribute<?, ?, ?> pluralAttr = pluralAttrPath.getAttribute();


Join<?, ?> join = from.join((SetAttribute<Object,?>)pluralAttr);

TypedQuery<Object> typedQuery = entityManager.createQuery(criteriaQuery.select(join));
return (List<P>)typedQuery.getResultList();

當我執行該行以實際返回結果時，將引發以下異常：

javax.persistence.PersistenceException: org.hibernate.exception.SQLGrammarException: could not execute query
    at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1235)
    at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1168)
    at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:250)
    at org.hibernate.ejb.criteria.CriteriaQueryCompiler$3.getResultList(CriteriaQueryCompiler.java:260)
    at temp.pack.dao.impl.DefaultDAOService.getProperties(DefaultDAOService.java:628)
...
Caused by: org.hibernate.exception.SQLGrammarException: could not execute query
    at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:92)
    at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
    at org.hibernate.loader.Loader.doList(Loader.java:2452)
    at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2192)
    at org.hibernate.loader.Loader.list(Loader.java:2187)
    at org.hibernate.hql.classic.QueryTranslatorImpl.list(QueryTranslatorImpl.java:936)
    at org.hibernate.engine.query.HQLQueryPlan.performList(HQLQueryPlan.java:196)
    at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1258)
    at org.hibernate.impl.QueryImpl.list(QueryImpl.java:102)
    at org.hibernate.ejb.QueryImpl.getResultList(QueryImpl.java:241)
    ... 20 more
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column '2L' in 'where clause'
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:409)
    at com.mysql.jdbc.Util.getInstance(Util.java:384)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1054)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3562)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3494)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1960)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2114)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2696)
    at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2105)
    at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:2264)
    at com.jolbox.bonecp.PreparedStatementHandle.executeQuery(PreparedStatementHandle.java:179)
    at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:208)
    at org.hibernate.loader.Loader.getResultSet(Loader.java:1869)
    at org.hibernate.loader.Loader.doQuery(Loader.java:718)
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:270)
    at org.hibernate.loader.Loader.doList(Loader.java:2449)
    ... 27 more

Role和Permission類已與JPA和一些Hibernate注釋映射，如下所示：

public abstract class Role implements Serializable {

 /**
  * The id of this role. Internal use only.
  * 
  * @since 1.0
  */
 @Id @GeneratedValue
 protected long id;

 /**
  * Set of permissions granted to this role.
  * 
  * @since 1.0
  */
 @OneToMany(cascade = { CascadeType.PERSIST, CascadeType.MERGE }, mappedBy="sourceRole")
 protected Set<Permission> permissions = new HashSet<Permission>();

...

}

public class Permission implements Serializable {
 private static final long serialVersionUID = 1L;

 /**
  * The id of this permission. Used internally for persistence.
  * 
  * @since 1.0
  */
 @Id @GeneratedValue
 @Column(name = "PERMISSION_ID")
 protected long id;

 /**
  * The group to which the owner of this permission is being granted permission to.
  * 
  * @since 1.0
  */
 @ManyToOne(cascade = { CascadeType.PERSIST, CascadeType.MERGE })
 @JoinColumn(name = "TARGET_ROLE_ID")
 @ForeignKey(name = "FK_TARGET_GROUP_PERMISSION_ID",
   inverseName = "FK_PERMISSION_ID_TARGET_GROUP")
 protected Group targetGroup;

 /**
  * The role that has been granted this permission.
  * 
  * @since 1.0
  */
 @ManyToOne(cascade = { CascadeType.PERSIST, CascadeType.MERGE })
 @JoinColumn(name = "SOURCE_ROLE_ID")
 @ForeignKey(name = "FK_SOURCE_GROUP", inverseName = "FK_GROUP_PERMISSIONS")
 private Role sourceRole;

...

}

此條件查詢有什么問題？

我期待對typedQuery.getResultList（）的調用返回僅包含一個元素的集合的列表：ID = 2的角色的權限對象的集合。這是試圖僅選擇（並初始化）“權限”從id = 2的對象角色收集。

我是標准查詢的新手，而且很難找到問題所在。

跟進：這是Hibernate試圖執行的查詢：

select permission1_.PERMISSION_ID as PERMISSION1_12_,
    permission1_.IS_REQUIRED as IS2_12_,
    permission1_.SOURCE_ROLE_ID as SOURCE3_12_,
    permission1_.TARGET_ROLE_ID as TARGET4_12_
from (
        select ROLE_ID,
        NAME,
        DESCRIPTION,
        IS_ACTION,
        LABEL,
        null as FIRST_NAME,
        null as LAST_NAME,
        null as PASSWORD_HASH,
        1 as clazz_ from GROUPS
    union
        select ROLE_ID,
            NAME,
            null as DESCRIPTION,
            null as IS_ACTION,
            null as LABEL,
            FIRST_NAME,
            LAST_NAME,
            PASSWORD_HASH,
            2 as clazz_ from USERS
    )
role0_ inner join PERMISSIONS permission1_ on role0_.ROLE_ID=permission1_.SOURCE_ROLE_ID
    where (role0_.ROLE_ID=2L )

顯然問題出在2L。 從MySQL的角度來看，2L實際上是一個字符串或一列，因為它上面帶有L並且沒有被引用。

這是Hibernate中的錯誤嗎？ 在我看來就像一個。 L不應出現在生成的SQL查詢中...

任何人都對發生的事情有任何想法嗎？ 在我看來，這將是一個重大錯誤，所有其他人都不會忽視這一錯誤，因此，我假設存在一個很好的變化，我做錯了什么。

謝謝！！

愛德華多

Answer 1

您可以為創建聯接條件的兩個表嘗試使用別名。 這也可能是問題，因為休眠僅為HQL和實體負載創建別名，但條件取決於用戶來創建別名。

Answer 2

通過將id屬性數據類型從long替換為Long解決了該問題。 這個簡單的更改使Hibernate開始在查詢中放置不帶L的2，並且不再發生任何故障。