transient

问题 I have JPA entities where some properties are annotated with @Transient . Should I use these properties in equals/hashCode/toString methods? My first thought is NO but I don't know why. Tips? Ideas? Explanations? 回答1: The case of toString() is different, you can do whatever you want with toString() so I will only cover equals() (and hashCode() ). First, the rule: if you want to store an object in a List , Map or a Set then it is a requirement that equals and hashCode are implemented so they

问题 I am serializing a POJO into JSON using Jackson 2.1.4 but I want to ignore a particular field from getting serialized. I used transient but still it is serializing that element. public class TestElement { int x; private transient String y; public int getX() { return x; } public void setX(int x) { this.x = x; } public String getY() { return y; } public void setY(String y) { this.y = y; } } I am serializing as following: public static void main(String[] args) throws JsonProcessingException {

问题 I am working on an NHibernate project and have a question regarding updating transient entities. Basically the workflow is as follows: Create a DTO (projection) and send over the wire to client. This has a small subset of properties from the entity. Client sends back the changed DTO Map the DTO properties back onto the appropriate enitity so an UPDATE statement can be generated and executed by NH. Save the entity Point 4 is where I have the issue. Currently I can achieve this update using the

问题 Ok, I initially wanted to make NSSortDescriptor of a request for NSFetchedResultsController to sort based on the property in my NSManagedObject subclass, but It obviously won't do it, because NSFetchedResultsController is limited to predicates and sort descriptors that work on the fetched entity and its relations, so I decided to create a transient attribute in my data model, synthesis the property for this attribute to ivar in my NSManagedObject subclass, and sort based on it. When running

问题 Ok, I initially wanted to make NSSortDescriptor of a request for NSFetchedResultsController to sort based on the property in my NSManagedObject subclass, but It obviously won't do it, because NSFetchedResultsController is limited to predicates and sort descriptors that work on the fetched entity and its relations, so I decided to create a transient attribute in my data model, synthesis the property for this attribute to ivar in my NSManagedObject subclass, and sort based on it. When running

问题 If I try to do 1000 000 assoc! on a transient vector, I'll get a vector of 1000 000 elements (count (let [m (transient [])] (dotimes [i 1000000] (assoc! m i i)) (persistent! m))) ; => 1000000 on the other hand, if I do the same with a map, it will only have 8 items in it (count (let [m (transient {})] (dotimes [i 1000000] (assoc! m i i)) (persistent! m))) ; => 8 Is there a reason why this is happening? 回答1: The transient datatypes' operations don't guarantee that they will return the same

问题 I just want to know what is the difference between all these annotations. Why are we using these... means they have no effect especially field level and property level. And what is the purpose of using mixed level annotation like: @Entity @Access(AccessType.FIELD) class Employee { // why their is a field level access private int id; // whats the purpose of transient here @Transient private String phnnumber; // why its a property level access @Access(AccessType.property) public String

问题 The problem is how to except an byte[] from serialization of XMLEncoder, but i need to save this field to DB. I have a Object public class MyClass1 implements Serializable { some properties ... private byte[] a01_14_01_content; getters and setters ... } and Encoder: import java.beans.XMLEncoder; public class MyEncoder{ ... public byte[] getBytes() { XMLEncoder e = new XMLEncoder(baos); e.writeObject(answer); e.close(); return baos.toByteArray(); } } I need to serialize all fields except array

问题 days is a transient variable in Calendar class. CalendarDay class has foreign key reference to Calendar class via the field called calendarId . When I fetch Calendar object, days field remains null. How can I populate the field? @Entity @Table(name = "calendars") @Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE) @Document(indexName = "calendars") public class Calendar extends Node { @Transient @OneToMany(fetch = FetchType.EAGER) @CollectionTable(name = "calendar_days", joinColumns

问题 No clue why I'm getting this error in my ASP MVC application: 'themeContext' is not a member of 'Transient.collection[MICSgroupHospital.Models.Theme(Nullable=True,DefaultValue=)]'. To extract a property of a collection element, use a sub-query to iterate over the collection. Near escaped identifier, line 1, column 16. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it