Here I talk about me in learning J2EE processes and talk about the experience and lessons of receipts in this process. In order to be less bent less.
Java has developed to now, according to application scores, three major blocks: J2SE, J2ME and J2EE. These three are complementary, the application range is different.
J2SE is the standard version of Java2, mainly used for desktop applications;
J2ME is primarily applied to embedding is system development, such as mobile phones and PDAs;
J2EE is a Java2's Enterprise Edition, mainly used for distributed network programs, such as e-commerce websites and ERP systems.
Learn J2SE first
To learn J2EE, you must first learn J2SE. Just start learning J2SE first, don't use IDE, then gradually transition to the development of IDE, after all, use it easy. Learn J2SE Recommend two books, "Java2 Core Technology, Chapter 2", "Java Programming Thought", "Java Mode". Among them, "Java Programming Thoughts" should be studied and intensive. This period of time is basic skill, the time will be very long, or it may be short, it depends on the level of the learner.
Don't be entangled by IDE
In the process of studying Java and J2EE, you will encounter a five-flowers of IDE, don't be confused, learn Java, you have to learn language itself, don't care too much about the additional features of the IDE, Java programming between different IDEs. It is easy, the function of too much Ide is easy to delay the understanding of the language itself. The current popular IDE has JBuilder, Eclipse, and Eclipse to enhance WSAD. It is possible to use one of them, it is recommended to start J2EE from Eclipse. Because JBuilder is more suitable for writing a J2SE program.
Select and learn server use configuration
When you have J2SE and IDE experience, you can start J2EE's learning, web server: Tomcat, do not doubt, Tomcat is preferred for learning Web services. The application server currently has three main: JBoss, WebLogic, WebSphere. There are many projects to start using jboss, and there are a lot of companies to start doing WebSphere or WebLogic transplantation to the JBoss application server (cost savings), what to say is, learning Tomcat and JBoss I think it is preferred, and it is the easiest to get started. Learning Server Use the configuration to ask questions about experienced people (with conditional words), because they can solve the problem, you can get online to explore it. You should have two days (I have to do this stupid), we should Put the main time in learning principles and theory, a particular technology uses to replace a person's knowledge and learning.
Learn Web Knowledge
If you are doing an e-commerce website, you may have to act as a few characters, this is what you still have to learn:
HTML, you might want to use DreamWave and other IDEs.
JavaScript, learn simple data verification, data linkage display, etc.
J2EEAPI learning
Learning J2EEAPI and learning servers should be an iteration process.
First learn JSP and servlet programming, a lot of books, I have established two "JSP Design" and "Java Servlet Programming" of Oreilly, and OREILLY is always excellent, I have to admire.
Learning a JDBC database programming, most of the J2EE project is a MIS system, and the access database is the core. This should belong to J2SE learning, here to take it out.
Learning JNDI API, it can be combined with learning EJB.
Learn EJB API, recommend book "Jing EJB"
After the above learning, it is probably possible to deal with the general application. Some people say that SUN's "J2EE Tutorial" is studying all the way, of course, can be.
Learn EJB design pattern and code code (most important)
The design pattern is practicing internal work. Its importance can be said, if you don't use the design mode, you will write a bunch of rubbish that use EJB, there is a bunch of bugs, the result is better not to implement EJB ( EJB is not equal to J2EE)
Regardless of the language of learning, you should look at a lot of code, you see the amount of code is less than a certain amount, it is not good J2EE.
There are currently many open source projects that can be used as a textbook:
JIVE Forum
PetStore SUN
Dune Sun
Wait, study one and use it to your own project.
J2EE Other learning
When you gradually understand J2EE, you have to pay attention to some of the technological changes in the current field, J2EE is a hundred hundred people standing, everyone is here to present their own solutions, such as Structs, Hiberate, OFBIZ, etc. These things should be determined by your projects and goals, pre-supplement that there is no taste, but do not need to be too deep, after all, learning principles and theories are the most important thing.
Currently J2EEAPI
JavaServer Pages (JSP) Technology 1.2
Java servlet technology 2.3
JDBC API 2.0
Java XML Processing API (JAXP) 1.1
Enterprise JavaBeans Technology 2.0
Java Message Service (JMS) 1.0
Java Name Directory Interface (JNDI) 1.2
Java Transaction API (JTA) 1.0
JavaMail API 1.2
JavaBeans Activation Architecture (JAF) 1.0
J2EE Connector Architecture (JCA) 1.0
Java Certification and Authorization Service (JAAS) 1.0
Learning some of the APIs to be determined by your project, understanding all them are good.
The above confirmed a word, Java language itself is not difficult, but there are too many technologies, so learn Java is very hard. Recalling, basically every beginner, may ask someone to ask others when just studying Java, which method do you know (API)? Oh, no one, only hand ripe.
