With the rapid development of web applications, developers need to solve more and more problems, such as increasing maintainability, improving development efficiency, reducing development difficulty, etc. For this reason, Java developers tend to use some open source frameworks, such as Struts2, etc., to reduce development pressure. So, what we are going to discuss here is the advantages and practical methods of using Struts2 for Web development in Java API development.
1. Introduction to Struts2
Struts2 is an open source, MVC-mode Web application framework based on the classic Struts architecture. Struts2 improves and simplifies classic Struts and adds new technologies to solve the shortcomings of Struts, such as limited access protocol capabilities and complex APIs. Struts2 is an interceptor-based framework, and its core idea is to encapsulate requests and responses through interceptors.
2. Controller in Struts2
In Struts2, the controller is the core of the Web application. It is responsible for responding to client requests and mapping the requests to relevant handlers. In Struts2, controllers are implemented by Action components and configured through XML configuration files or annotations.
1.Action implementation
The Action component processes the request and maps the request to the corresponding view. In Struts2, Action components can obtain data through the automatic assembly mechanism, automatic setting of request parameters, and automatic injection of request parameters.
2.XML configuration file
Through the XML configuration file, the controller can easily set dependencies between Action components. In Struts2, the controller is configured through the Struts.xml configuration file. This file describes the configuration of the main components, such as Action, interceptors, global results, etc. When the web application starts, the Struts2 framework starts and loads the Struts.xml file. This file is used throughout the life cycle of the application and is essential in the development and testing of the application.
3. Annotation method
In addition to XML configuration files, Struts2 also supports annotation method to define Action components. This approach can significantly reduce the number of XML configuration files, making them easier to maintain.
3. Interceptor in Struts2
The interceptor is one of the core components of the Struts2 framework. Its function is to encapsulate requests and responses in ActionContext and provide context information for Action.
1. Request interceptor
The request interceptor preprocesses the request. In Struts2, each request goes through a series of request interceptors, called the interceptor stack, which are executed on each request. The request interceptor is the main component of Struts2 in the request processing process.
2. Dynamic interceptor
Dynamic interceptor can process requests in a customized way, and applications can freely add and delete interceptors. Dynamic interceptors are mainly implemented by adding custom interceptors to Struts2.
4. Result component in Struts2
The Result component converts the result of Action execution into a view and presents it to the user. Among them, Struts2 has many built-in view components, such as JSP, Velocity, FreeMarker, JSON, Excel, etc.
5. Practical Method
In Java API development, the method of using Struts2 for Web development is as follows:
1. Configure the Struts.xml file
When developing a Java API, you need to define all Action components of the project and configure these components into the Struts.xml file. In addition, request interceptors and dynamic interceptors need to be defined in the Struts.xml file to achieve program control.
2. Define Action components
After defining the Struts.xml file, you need to define all Action components and associate them with the corresponding view components. When defining an Action component, you can annotate the component or configure it in an XML file.
3. Write the view component
After the Action component processes the request, it needs to convert the result into a view component and present it to the user. When developing Java API, you can use the built-in view components of Struts2, or you can write your own view components to implement functions.
Summary
This article briefly introduces the method of using Struts2 for Web development in Java API development, including an introduction to Struts2, controllers, interceptors, Result components and practical methods. With the rapid development of the Internet, Web applications have become an important part of Java API, and Struts2, as a component in the MVC framework, plays a vital role in Java API. Using Struts2 can not only improve development efficiency, but also improve program maintainability and reduce development difficulty.
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