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Java 在googleappengine中创建实体_Java_Google App Engine_Google Cloud Datastore - Fatal编程技术网

Java 在googleappengine中创建实体

Java 在googleappengine中创建实体,java,google-app-engine,google-cloud-datastore,Java,Google App Engine,Google Cloud Datastore,不确定这是否可行,但总是值得一问 我简化了下面的问题-基本上,我想使用for循环来创建多个相同类型的实体。问题似乎是我无法通过调用变量来命名新实体 有人能想出解决这个问题的办法吗?任何帮助都将不胜感激 非常感谢 DatastoreService datastore = DatastoreServiceFactory.getDatastoreService(); Key roomkey = KeyFactory.createKey("E15", "ids"); String test = "";

不确定这是否可行,但总是值得一问

我简化了下面的问题-基本上,我想使用for循环来创建多个相同类型的实体。问题似乎是我无法通过调用变量来命名新实体

有人能想出解决这个问题的办法吗?任何帮助都将不胜感激

非常感谢

DatastoreService datastore = DatastoreServiceFactory.getDatastoreService();
Key roomkey = KeyFactory.createKey("E15", "ids");

String test = "";
for (int x = 0; x < 7; x++) {
   test = ("" + Integer.toString(x));
   Entity test = new Entity("E15", roomkey);
}
DatastoreService datastore=DatastoreServiceFactory.getDatastoreService();
Key roomkey=KeyFactory.createKey(“E15”、“ids”);
字符串测试=”;
对于(int x=0;x<7;x++){
test=(“”+Integer.toString(x));
实体测试=新实体(“E15”,roomkey);
}

您还可以通过为实体指定关键字名称或id来创建实体:

Entity entry = new Entity("E15", key_name, roomkey);
或者

稍后,您可以获得实体:

Key key = KeyFactory.createKey(roomkey, "E15", id);
Entity entry = datastore.get(key);

假设您试图创建7个类型为E15的实体,其键名为“0”到“6”

DatastoreService datastore=DatastoreServiceFactory.getDatastoreService();
对于(整数n=0;n<7;++n){
实体=新实体(“E15”,n.toString());
datastore.put(实体);
}

最后一点很重要。仅仅创建
实体的实例
并不能持久化它。

不需要在标题中添加主标记。
Key key = KeyFactory.createKey(roomkey, "E15", id);
Entity entry = datastore.get(key);
Entity entity = new Entity("YourKindName",String|Long);

Entity entity = new Entity("YourKindName",""+x);//using string as key
//or
Entity entity = new Entity("YourKindName",x);//using number as key
DatastoreService datastore = DatastoreServiceFactory.getDatastoreService();
for (Integer n = 0 ; n < 7 ; ++n ) {
    Entity entity = new Entity("E15", n.toString());
    datastore.put(entity);
}