Development Status and Analysis of Java EE Development

JSF 2.0

 

Despite the fierce competition of Java in the presentation layer framework, JSF still sticks to its own territory. Although there are many questions about JSF's ease-of-use and robustness, jsf2.0 is designed to solve these problems positively. Its ease-of-use, innovation, and scalable features include:

 

JSF officially uses facelets as the view technology. Maybe you are not familiar
Facelets is also an open-source view technology that integrates with JSF. Therefore, unlike JSP, facelets is more suitable for JSF.
The component model and the concept of lifecycle. Of course, maybe the most powerful feature of facelets is to replace Java with mark-up.
Code to create custom components. The complexity of creating custom components may be the biggest complaints from developers about JSF.

 

Jsf2.0 provides Java ee 5 based on tags
Configuration features of the annotation Driver (for example, you can use @ managedbean and @ managedproperty
). This also means that the size of the faces-config.xml file can be reduced to some extent, but the configuration of those nodes like in navigation in XML
The number of files is not small.

 

Jsf2.0 changed its lifecycle to adapt to Ajax, and only needed to handle partial pages by Ajax events. This feature makes the combination of JSF and Ajax more natural.

 

Jsf2.0 now has a built-in excellent resource processor. Outstanding Performance in images, JavaScript files, and CSS styles. It can better reference resources through logical names, resource groups, and versions.

 

In addition to the above features, jsf2.0 also includes many other convenient changes. For example, event and support
The development style (ROR) of rails_env supports expansion of standard component sets. You can see jsf2.0 through the link below
Public draft: http://jcp.org/en/jsr/detail? Id = 314

 

Ejbs 3.1

 

EJB in Java ee 5
We have already experienced a lot of changes. Maybe it seems impossible, but in fact ejb3.0
Still widely recognized in the community, and people adopting it are also growing. This may be because we think too much about how to simplify Java ee 5.
To achieve this. For example, interest in JBoss Seam and enthusiasm for glassfish are key factors. Ejb3.1
The goal is to keep EJB as simple as possible when adding business components. The following is a high-level summary of ejb3.1 features:

 

The service interface that originally required or even implemented session beans became optional and is no longer required. It is particularly useful when session beans + JSF + webbeans are used.

 

Ejb3.1 adds the concept of Singleton beans. Because people are more inclined to manage the state of shared applications, it is necessary to ensure that the model is completely thread-safe. In addition, the declarative concurrency control added by ejb3.1 is more flexible.

 

Ejb3.1 a powerful feature that supports Cron-style scheduling. Besides the timer Scheduling Based on the timer API, the declarative and programmatic Cron-style scheduling APIs are also added.

 

Another powerful feature is that you can use @ asynchronous annotation to call the Session Bean method asynchronously. You even use it to control the asynchronous EJB method and return a java. util. Concurrent. Future object.

 

The concept of ejb3.1 Lite is gradually introduced to form an EJB API
And get the application in the Web profile. However, EJB lite includes features such as transaction processing and security, and those message mechanisms, remote calls and
Scheduling and other non-essential elements do not need to be added. In addition to the features described in the list above,

 

Features of ejb3.1 include: You can directly package ejbs into war files and run them in
Embedded Containers facilitate JUnit testing in the Java SE environment and use a unified standardized global JNDI naming method. Ejb3.1
The public draft can be obtained from the following link: http://jcp.org/en/jsr/detail? Id = 318

 

JPA 1, 2.0

 

By the time Java EE 6 was reached, JPA had been completely removed from EJB
To form its own system (ejb3.0 has separated JPA). JPA
There is no doubt about the success. It is widely accepted by the community and supported by top-class suppliers. Originally, we were worried that the collapse of ejb2. *'s enity beans may not make Java
EE once again leads the persistence layer standards. One important factor for success is the unambiguous support of gaving King and the JBoss community. Jpa2.0
The goal is to make persistent efforts on the basis of this success to fill more gaps and create more innovations:

 

Jpa2.0 has added a large number of required ORM ing enhancement features, including support for using
@ Elementcollection annotation to enhance collections, maps and lists (not the association between objects here)
Set, supports one-to-one association of map (jpa1.0 only supports two-way one-to-one association ).

 

Entitymanager and query API
Are all improved. For example, you can obtain the first record from the result set directly (jpa1.0 only allows reverse return of a single record from a unique result set), specifying
The maximum value of the query result set. Access the underlying object manager or query of each supplier, and add a pessimistic lock (jpa1.0 only supports optimistic locks.
).

 

Jpql also provides functions similar to SQL such as case, nullif, and coalesce.

 

The criteria API is added to jpa2.0 at the request of developers.
If hibernate or toplink's criteria API is unfamiliar, you can think of it as a Java
Object-oriented, thread-safe, and a set of APIs that can be equals to jpql. These APIs are suitable for compiling complex dynamic query statements and avoid parsing jpql
Statement.

 

More complete features of Japan include: Standard second-level cache and standard JDBC
Properties, specify the timeout time, and so on. You can view more details about the jpa2.0 public draft at any time through the following JSR site:

Http://jcp.org/en/jsr/detail? Id = 317

(Responsible editor: Dong Jianwei)

 

From: http://java.ccidnet.com/art/12011/20090217/1678897_1.html