Design Pattern importance

J2EE is a framework software. What is Framework software? It is different from the Java APIs we used previously, which belong to Toolkist (Toolkit). It is no longer passively used or called, but deeply involved in a field, the purpose of the framework software design such as J2EE is to first define the unchanged things in a field, such as the overall structure and some main responsibilities (such as database operation Transaction Tracking security ), the rest is the changing things. The specific changing requirements for specific applications in this field are what J2EE programmers need to do.

Many people did not notice this. After learning the Basic Java language, they went to learn J2EE directly. Some even ran away and used Weblogic and other specific J2EE software directly. After a while, they found that, it's easy to use, but do you really understand J2EE? Is your application in specific cases also extending the idea of J2EE?

If you can't extend the idea of J2EE well, wouldn't you be a blockbuster? It's wise to realize that J2EE is not suitable for everyone, at least, however, we need to use J2EE in a proper place. Only by understanding the essence of J2EE framework software can you use Java flexibly to solve your problem, you can even build your own enterprise framework. (We cannot always use frameworks set by others. Why cannot we have our own frameworks ?)

Java provides a wide range of APIs and a powerful database system for underlying support, so our programming seems to have become a simple "Patchwork" and call similar to building blocks, some people even advocate "blue-collar programmers", which are not familiar with modern programming technologies.

In truly reusable object-oriented programming, GoF's Design Pattern provides us with a set of reusable Object-oriented technologies, coupled with Refactoring ), therefore, there are few simple repetitive tasks, and Java code refinement and object-oriented purity (the design pattern is the soul of java ), programming becomes an exciting process that allows you to experience creative pleasure at all times.

If you have some experience in Object-Oriented Programming, you will find that you have used some of the design patterns unconsciously. If you are a newbie, from the very beginning, cultivate your own good programming habits (to make your program use a common pattern for others' understanding; To reduce repetitive programming work ), this is undoubtedly a prerequisite for becoming a good programmer.
The entire design pattern runs through one principle: interface programming rather than implementation.
The goal principle is to reduce coupling and enhance flexibility.