JAVA, it is necessary to master the two architectures of Model1 and Model2. Let's look at the following together from Model1 to Model2 (MVC) and
A magnificent transition to a typical three-tier architecture.
Model1 Architecture
In simple terms, MODEL1 is implemented with JSP as its core. The JSP page responds to the client request on its own and returns the processing results to the customer, on the JSP page
business logic, service-side processing, and HTML, and so on The JSP page enables both business logic and process control to quickly open
Hair
Advantages
Simple architecture, fast development, suitable for small project development.
Disadvantages
JSP is overloaded with responsibility and violates the single principle of responsibility
JSP embedded in a large number of Java, HTML generation code that causes duplicate code too much, not easy to maintain
Not conducive to response to demand changes, high coupling and low scalability
Model2 (MVC) Architecture
Based on a series of shortcomings of MODEL1 architecture exposure, Model2 the task separation of JSP on the basis of Model1 abstraction out the control layer, will get the parameter
calls to the servlet processing, JSP is responsible for page display display. As a result, Model2 can also be understood as a simple MVC pattern.
Advantages
Clear responsibilities, more suitable for the development of large-scale projects.
Facilitates the division of labor and facilitates management
Facilitates component reuse with low coupling levels
Better response to demand changes and higher scalability
Disadvantages
Too many layers, increasing the complexity of system development
Not suitable for small project development
three-tier architecture
In the actual development process, we will find that the MODEL2 architecture also has some obvious flaws, such as the original only need to display the name and age of two letters
need to display gender information at the same time, you need to modify the business logic the code implementation of the layer violates the closure principle. In this case, we will consider
Model2 further abstraction, extracting operations from the database to the persistence logic layer implementation.
This is a very typical three-tier architecture UBD mode. u layer, jsp/servlet, mainly responsible for the foreground display;b layer, business logic layer, mainly responsible for various
Business the processing of logic; layer D: persistence layer, mainly responsible for a series of operations on the database. The three-tier architecture clearly divides the responsibilities of each layer, reducing the coupling
Flexibility of the program.
Keyword: Model1 Model2 three-tier architecture JSP Servlet
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Java Highlights (iii)--MODEL1, MODEL2, three-tier architecture with gorgeous transitions