Question

我有部门和员工实体。 Employee表有三列：

DEPARTMENT_ID
KEY
VALUE

在Employee表中的非null键插入中插入null值。我在更新期间收到NullPointerException prop.put(key, value)期间现有密钥的非空值：

java.lang.NullPointerException at java.util.Hashtable.put（Hashtable.java:514）at org.eclipse.persistence.indirection.IndirectMap.put（IndirectMap.java:543）在 org.eclipse.persistence.internal.queries.MapContainerPolicy.addInto（MapContainerPolicy.java:131）在 org.eclipse.persistence.internal.queries.MappedKeyMapContainerPolicy.addInto（MappedKeyMapContainerPolicy.java:196）在 org.eclipse.persistence.queries.DataReadQuery.executeNonCursor（DataReadQuery.java:226）在 org.eclipse.persistence.queries.DataReadQuery.executeDatabaseQuery（DataReadQuery.java:152）在 org.eclipse.persistence.queries.DatabaseQuery.execute（DatabaseQuery.java:899）在 org.eclipse.persistence.queries.DataReadQuery.execute（DataReadQuery.java:137）在 org.eclipse.persistence.queries.DatabaseQuery.executeInUnitOfWork（DatabaseQuery.java:798）在 org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.internalExecuteQuery（UnitOfWorkImpl.java:2896）在 org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery（AbstractSession.java:1804）在 org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery（AbstractSession.java:1786）在 org.eclipse.persistence.internal.indirection.QueryBasedValueHolder.instantiate（QueryBasedValueHolder.java:129）在 org.eclipse.persistence.internal.indirection.QueryBasedValueHolder.instantiate（QueryBasedValueHolder.java:116）在 org.eclipse.persistence.internal.indirection.DatabaseValueHolder.getValue（DatabaseValueHolder.java:89）在 org.eclipse.persistence.internal.indirection.UnitOfWorkValueHolder.instantiateImpl（UnitOfWorkValueHolder.java:173）在 org.eclipse.persistence.internal.indirection.UnitOfWorkValueHolder.instantiate（UnitOfWorkValueHolder.java:234）在 org.eclipse.persistence.internal.indirection.DatabaseValueHolder.getValue（DatabaseValueHolder.java:89）在 org.eclipse.persistence.indirection.IndirectMap.buildDelegate（IndirectMap.java:109）在 org.eclipse.persistence.indirection.IndirectMap.getDelegate（IndirectMap.java:329）在 org.eclipse.persistence.indirection.IndirectMap.put（IndirectMap.java:543）

EclipseLink版本为2.5.2

我有部门和员工实体，部门实体类与员工实体有以下关系：

@Entity
@Table(name = "DEPARTMENT" uniqueConstraints = {
    @UniqueConstraint(columnNames  = { "NAME" }) })
@NamedQueries( {
  @NamedQuery(name = Department.findAll", query = "select d from Department  d"),
 @NamedQuery(name = Department.findByName", query = "select d from Department  d WHERE d.name = :name")})

public class Department implements Serializable { 

    @ElementCollection
    @MapKeyColumn( name = "KEY")
    @Column( name = "VALUE")
    @CollectionTable(name="DEPARTMENT_PROP", joinColumns =     @joinColumn(name= "DEPARTMENT_ID))
    private final Map<String, String> props = new HashMap();


   public Map<String, String> getProperties() {
      return properties;
   }

Answer 1

实体类的方法或持久性实例变量都不是 <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script> <div id="my-container-div">container</div> <input type="checkbox" value="0" /> <input type="checkbox" value="1" /> <input type="checkbox" value="2" />。从final中删除了此修饰符，映射注释看起来很好。

请注意，在java版本7中，您不能放置空值，因为props不允许它，正如您在异常日志中看到的那样，它是EclipseLink的map实现使用。请参阅this java oficial doc。

实体更新会为Map的@ElementColection抛出NPE

1 个答案: