標籤彙整: java abstract class
Installing Oracle Java SE 11 on Ubuntu 18.04
This article is a quick guide for Ubuntu Linux users installing Java 11, the current long-term support (LTS) Java version. I’ll briefly make the case for migrating your code base to Java 11, then guide you through the steps to install Oracle JDK 11 … 閱讀全文
By: vladmihalcea
The mapping is wrong. Check out my <a href=”https://vladmihalcea.com/books/high-performance-java-persistence/”>High-Performance Java Persistence book</a> for a detailed explanation about how you should map this association to get the most out of your data access layer. 閱讀全文
By: Henry
Hi Vlad, thanks for your blogs on JPA and Hibernate.
In my codebase, I found a <code>Student</code> and <code>Course</code> entity classes with the below relationships.
The <code>Student</code> Entity:
[code lang=”java”]
@OneToMany(cascade = CascadeType.ALL,
fetch = FetchType.LAZY,
mappedBy = “student”)
private List courseList = new ArrayList<>();
[/code]
And the <code>Course</code> entity:
[code lang=”java”]
@OneToOne(fetch = FetchType.LAZY)
@JoinColumn(name = “STUDENT_ID”, nullable = false)
private Student student;
[/code]
I thought in the <code>Course</code> entity, the inverse annotation would be a <code>@ManyToOne</code> but I found a <code>@OneToOne</code>. Is this possible given your statement in one of your article:
“The bidirectional association requires the child entity mapping to provide a @ManyToOne annotation, which is responsible for controlling the association.”
Thanks 閱讀全文
When to use composition vs inheritance
In Java 101: Inheritance in Java, Part 1, you learned how to leverage inheritance for code reuse, by establishing is-a relationships between classes. Composition is a closely related programming technique that is used to establish has-a relationships i… 閱讀全文
Composite keys in JPA and Hibernate
Every JPA entity has a primary key, but some entities have more than one value as their primary key. In this case, you need to use a composite key. This Java tip introduces you to using composite keys in JPA and Hibernate.To read this article in full, … 閱讀全文
Inheritance relationships in JPA and Hibernate
Inheritance is a common pattern in object-oriented programming, but it’s not easily replicated in a database. This Java tip shows you how to model inheritance relationships in JPA with Hibernate.To read this article in full, please click here(Insider S… 閱讀全文
Java Tip: Hibernate validation in a standalone implementation
A good data validation strategy is an important part of every application development project. Being able to consolidate and generalize validation using a proven framework can significantly improve the reliability of your software, especially over … 閱讀全文
Hibernate validation in a standalone implementation
A good data validation strategy is an important part of every application development project. Being able to consolidate and generalize validation using a proven framework can significantly improve the reliability of your software, especially over t… 閱讀全文
Java Tip: Consuming SharePoint web services with a Java client
I used to think that a Camel was something to smoke or ride in the desert, but that was before I opened my mouth at work one day and said, “Sure I can automatically save these documents up to SharePoint.” SharePoint has been around for a long time,… 閱讀全文
Consuming SharePoint web services with a Java client
I used to think that a Camel was something to smoke or ride in the desert, but that was before I opened my mouth at work one day and said, “Sure I can automatically save these documents up to SharePoint.” SharePoint has been around for a long time, … 閱讀全文
