標籤彙整:java array length

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. 繼續閱讀

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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 繼續閱讀

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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 … 繼續閱讀

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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,… 繼續閱讀

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Java Tip: Write an SOA integration layer with Apache Camel

In this Java tip, learn how to use Apache Camel to develop a quick-and-easy integration layer for a service-oriented architecture. Apache Camel lets you configure Camel integration components for web service endpoints; message transformation, routi… 繼續閱讀

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Java Tip: Orthogonality by example

Orthogonality is a concept often used to describe modular and maintainable software, but it’s more easily understood by way of a case study. In this article, Jens Dietrich demystifies orthogonality and some related design principles by demonstrating their use in the popular Log4j utility library. He also discusses how Log4j violates orthogonality in a couple of instances and discusses possible workarounds to the issues raised.

The concept of orthogonality is based on the Greek word orthogōnios, meaning “right-angled.” It is often used to express the independence between different dimensions. When an object moves along the x-axis in a three-dimensional space, its y and z coordinates don’t change. Change in one dimension does not cause change in another dimension, which means that one dimension cannot cause side-effects for others.

To read this article in full, please click here

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Java tip: Deploying JavaFX apps to multiple environments

JavaFX 2.0.2 and successor SDKs let you deploy JavaFX applications in multiple environments including as a standalone app, via Java Web Start, or embedded in a web page. Jeff Friesen follows up his recent introduction to JavaFX 2.0 with this short … 繼續閱讀

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Java Tip 143: Utilize the Database Schema Browser

The Database Schema Browser utility uses Java Database Connectivity (JDBC) APIs DatabaseMetaData and ResultSet to fetch information from a database and display it to users.This simple servlet provides users with customizable options to retrieve a listi… 繼續閱讀

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Java Tip 143: Utilize the Database Schema Browser

The Database Schema Browser utility uses Java Database Connectivity (JDBC) APIs DatabaseMetaData and ResultSet to fetch information from a database and display it to users.This simple servlet provides users with customizable options to retrieve a listi… 繼續閱讀

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Java Tip 142: Pushing JButtonGroup

Swing has many useful classes that make graphical user interface (GUI) development easy. Some of these classes, however, are not well implemented. One example of such a class is ButtonGroup. This article explains why ButtonGroup is poorly designed and … 繼續閱讀

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