java - 如何使用 JDOQL 检索作为类属性的对象列表？

Question

我有下一个具有持久性的类:

@PersistenceCapable
public class AppAccount {
     @PrimaryKey
     @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
     private Long id;

    @Persistent
    private String companyName;
    @Persistent
    List<AppUser> users = new ArrayList<AppUser>();
        // Getters and Setters and other properties
    }


@PersistenceCapable
@EmbeddedOnly
public class AppUser {

    @Persistent
    private String username;

    @Persistent
    private String firstName;

    @Persistent
    private String lastName;
        // Getters and Setters and other properties
}

基于应用程序帐户 ID，我想检索用户列表:

public static List<AppUser> getUsers(Long application_id) {
    PersistenceManager pm = JdoUtil.getPm();
    Query q = pm.newQuery(
        " select users " +
        " from " + AppAccount.class.getSimpleName() + 
        " where id == idParam" +
        " parameters Long idParam");        
    return (List<AppUser>) q.execute(application_id);
}

我得到下一个错误:

WARNING: Candidate class for JDOQL single-string query (AppAccount) could not be resolved
AppAccount
org.datanucleus.exceptions.ClassNotResolvedException: AppAccount
    at org.datanucleus.util.Imports.resolveClassDeclaration(Imports.java:194)
    at org.datanucleus.store.query.AbstractJDOQLQuery.<init>(AbstractJDOQLQuery.java:114)
    at org.datanucleus.store.appengine.query.JDOQLQuery.<init>(JDOQLQuery.java:65)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
    at org.datanucleus.plugin.NonManagedPluginRegistry.createExecutableExtension(NonManagedPluginRegistry.java:572)
    at org.datanucleus.store.appengine.DatastorePluginRegistry.createExecutableExtension(DatastorePluginRegistry.java:124)
    at org.datanucleus.plugin.PluginManager.createExecutableExtension(PluginManager.java:324)
    at org.datanucleus.store.query.QueryManager.newQuery(QueryManager.java:203)
    at org.datanucleus.jdo.JDOPersistenceManager.newQuery(JDOPersistenceManager.java:1291)
    at org.datanucleus.jdo.JDOPersistenceManager.newQuery(JDOPersistenceManager.java:1234)
    at com.softamo.pelicamo.invoices.server.Store.getUsers(Store.java:44)
    at com.softamo.pelicamo.invoices.test.server.StoreTest.testGetUsers(StoreTest.java:40)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
    at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:46)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

Answer 1

为什么要使用 getSimpleName() ，因为它只是放置类名？根据 JDO 规范，JDOQL 需要类名，包括包(getName() 更好)。此外，无论 Google 告诉您什么，您都不需要在字符串字段上使用 @Persistent :-P Saludos