DataNucleus + JDO：使用复合键检索对象（错误：NoSuchElementException）

Question

我有一个 ComposedIdKey 类，用于为 Customer 类创建复合键。 我可以使用复合键成功地将这个对象插入到 Hbase 中。 但是，当我尝试访问该对象时，会收到以下消息：

java.util.NoSuchElementException
        at java.util.StringTokenizer.nextToken(StringTokenizer.java:349)
        at DN_Schema.ComposedIdKey.<init>(ComposedIdKey.java:26)
        at DN_Schema.Customer_JDO3.dnNewObjectIdInstance(Customer_JDO3.java)
        at org.datanucleus.enhancer.EnhancementHelper.newObjectIdInstance(EnhancementHelper.java:221)
        at org.datanucleus.identity.IdentityManagerImpl.getApplicationId(IdentityManagerImpl.java:479)
        at org.datanucleus.ExecutionContextImpl.newObjectId(ExecutionContextImpl.java:3729)
        at org.datanucleus.api.jdo.JDOPersistenceManager.newObjectIdInstance(JDOPersistenceManager.java:1595)
        at org.datanucleus.api.jdo.JDOPersistenceManager.getObjectById(JDOPersistenceManager.java:1723)
        at Performance.DataNucleusPerfo.Read_Hbase(DataNucleusPerfo.java:109)

组合的IdKey

public class ComposedIdKey implements Serializable
{
    public String firstName;
    public String lastName;
    public String dateOfBirth;

    public ComposedIdKey ()
    {
    }

    /**
     * Constructor accepting same input as generated by toString().
     */
    public ComposedIdKey(String value)
    {
        StringTokenizer token = new StringTokenizer (value, "::");
        token.nextToken();               // className
        this.firstName = token.nextToken(); // field1
        this.lastName = token.nextToken(); // field2l
        this.dateOfBirth = token.nextToken(); // filed3
    }

    public boolean equals(Object obj)
    {
        if (obj == this)
        {
            return true;
        }
        if (!(obj instanceof ComposedIdKey))
        {
            return false;
        }
        ComposedIdKey c = (ComposedIdKey)obj;

        return firstName.equals(c.firstName) && lastName.equals(c.lastName) && dateOfBirth.equals(c.dateOfBirth);
    }

    public int hashCode ()
    {
        return this.firstName.hashCode() ^ this.lastName.hashCode() ^ this.dateOfBirth.hashCode() ;
    }

    public String toString ()
    {
        // Give output expected by String constructor
        return this.getClass().getName() + "::"  + this.firstName + "::" + this.lastName + "::" + this.dateOfBirth;
    }
}

我用来获取对象的代码：

Transaction tx = pm.currentTransaction();
        System.out.println("Retrieving Customer");
        Customer_JDO3 teste = null;
     try
            {
                tx.begin();
                teste = pm.getObjectById(Customer_JDO3.class,"10-10-10DataNucleus");

Hbase中的rowkey出现10-10-10DataNucleus

我做错了什么？ 谢谢

Answer 1

我认为您尝试将 ctor 的条目与“::”分开，但该条目不包含此类字符。