嵌入式类中的JDO - HashMap

问题描述

您是否可以在App Engine的嵌入式类中存储HashMap？
我有以下类：

pre $ @Persistent（serialized =true）
@Embedded
个人统计数据;

@PersistenceCapable
@EmbeddedOnly
public static class Stats实现Serializable {
private static final long serialVersionUID = 1L;
@Persistent（serialized =true，defaultFetchGroup =true）
私人地图< String，Integer>要求;
$ b public Stats（）{
requests = new HashMap< String，Integer>（）;




但是，当我尝试将项目添加到HashMap并坚持它我得到以下错误：

指定的类类com.google.appengine.api.datastore.Blob不可持久化

我知道你可以在普通类中成功使用HashMap，但是它们也可以用于嵌入类吗？

谢谢

解决方案

我没有用Embedded类试过它，但是我的JDO对象内的Maps需要额外的FetchGroup注解在包含类...

$ p $ @SuppressWarnings（serial

）
@PersistenceCapable（identityType = IdentityType.APPLICATION，detachable =true）
@FetchGroup（name =QueryAggregationJobJDO，members = {
@Persistent（name =appName，recursionDepth = -1），
等...
public class QueryAggregationJobJDO extends AggregationJobJDO implements SystemObject {
@Persistent（serialized =true）//这是应用程序名称字符串和每个找到的名称的计数
public Map<字符串，长> appName = new HashMap< String，Long>（）;


我们必须在打开DataManager时使用getFetchPlan（）添加此类...

  @Override 
 public boolean open（）{
 DataAreaManager dataAreaManager = new DataAreaManager（）; 
 dataAreaManager.setDataArea（VERSION_DATA_AREA）; （（pm == null）||（pm.isClosed（）））{
 
 pm = PMF.get（type）.getPersistenceManager（）; 
 
 if 
 pm.getFetchPlan（）。addGroup（TouchActiveUserJDO）; 
 pm.getFetchPlan（）。addGroup（UserRoleJDO）; 
 pm.getFetchPlan（）。addGroup（QueryAggregationJobJDO）; 
  

Are you able to store a HashMap within an embedded class on App Engine?I have the following Class:

@Persistent(serialized = "true")
@Embedded
private Stats stats;

@PersistenceCapable
@EmbeddedOnly
public static class Stats implements Serializable {
    private static final long serialVersionUID = 1L;
    @Persistent(serialized = "true", defaultFetchGroup="true")
    private Map<String, Integer> requests;

    public Stats() {
        requests = new HashMap<String, Integer>();
    }
}

However, when I attempt to add an item to the HashMap and persist it I get the following error:

Specified class class com.google.appengine.api.datastore.Blob is not persistable

I know you can successfully use a HashMap in a "normal" class but can they be used in embedded Class's also?

Thanks

解决方案

I haven't tried it with an Embedded class, but my Maps inside JDO objects needed additional FetchGroup annotations on the containing class...

    @SuppressWarnings("serial

        ")
        @PersistenceCapable(identityType=IdentityType.APPLICATION, detachable="true")
        @FetchGroup(name="QueryAggregationJobJDO", members={
                                                @Persistent(name="appName", recursionDepth=-1),
etc....
        public class QueryAggregationJobJDO extends AggregationJobJDO implements SystemObject {
            @Persistent(serialized="true")  // this is string of app names and a count for each name found
            public Map< String, Long >  appName = new HashMap<String, Long>();

and we had to add this class with getFetchPlan() when opening our DataManager...

@Override
public boolean open() {
    DataAreaManager dataAreaManager = new DataAreaManager();
    dataAreaManager.setDataArea(VERSION_DATA_AREA);

    if ((pm == null) || (pm.isClosed())) {

        pm = PMF.get(type).getPersistenceManager();
        pm.getFetchPlan().addGroup("TouchActiveUserJDO");
        pm.getFetchPlan().addGroup("UserRoleJDO");
        pm.getFetchPlan().addGroup("QueryAggregationJobJDO");

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