This is the 14th day of my participation in the August More Text Challenge. For details, see:August is more challenging
Let’s start with the history of Struts2.
Struts1
- Is the first PUBLISHED MVC framework in the world
- It was released in 2001
Struts2
- It’s not an upgrade to Struts1
- It’s based on WebWork
- Take advantage of both Struts1 and WebWork
So what exactly is Struts2? Struts2 is a framework for developing MVC applications. It provides solutions to some common problems in Web application development:
- Management of page navigation activities
- Validity verification of user input data
- Unified layout
- scalability
- Internationalization and localization
- Support for Ajax
- Duplicate submission of forms
We assume a scenario, there are multiple links in a JSP page, click on each link to the corresponding processing, each corresponding to a Java class, hyperlinks in the class there is a way, our purpose is to click on a hyperlink call the corresponding method of Java classes, for such a scenario, we have two solutions, One is to call Java classes through servlets, and the other is to call Java classes through filters. However, both methods are cumbersome, with a lot of repetitive code, and the Struts2 framework is a very useful tool to help solve this problem.
So, how do you set up a Struts2 development environment? To set up a Struts2 environment, we generally need to do the following steps:
- Create a JavaWeb project
- Find the JAR files you need to develop your Struts2 application
- Creating a JSP file
- Create the action file
- Write a Struts2 configuration file
- Add Struts2 MVC framework startup configuration to web.xml
We followed the steps step by step. Create a Web project named test0425_structs2. Then there are the jar packages. Struts2 has a lot of jar packages.
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Importing these key JARS into the project completes the second step. Let’s take a look at what these JARS do. Struts2-core-2.3.1.1. jar: Struts2 core class library xwork-core-2.3.1.1.jar: Command mode framework,WebWork and Struts2 are based on xwork ogNL-3.0.3. jar: Object Graph Navigation Language. The Struts2 framework reads and writes Object properties from and freemarker-2.3.18.jar: The Struts 2 UI tag template uses FreeMarker to write Commons-logging-1.1.x. jar: a logging package produced by ASF. The Struts 2 framework uses this logging package to support Log4J and JDK 1.4+ logging. Commons -fileupload-1.2.2.jar: Commons -io-2.0.1.jar: Commons -lang-2.5.jar: Commons -lang-2.5.jar: Asm-3.3. jar: provides bytecode read and write functionality, including the core functionality that other JARS are based on. Asm-commons -3.3.jar: provides event-based presentation. Asm-tree-3.3.jar: Provides an object-based representation. Javassist-3.11.0.ga.jar: Code generation tool that Struts2 uses to extend Java classes at run time
Next, create a few JSP files and post the code directly up. Create a new primer folder and create text.jsp in that folder
<%@ page language="java" pageEncoding="utf-8" contentType="text/html; charset=utf-8"%>
<%@ taglib uri="/struts-tags" prefix="s"%>
<html>
<head>
<title>My JSP 'index.jsp'< span style = "box-sizing: border-box; color: RGB (74, 74, 74); line-height: 20px; white-space: normal;"${pageContext.request.contextPath }/primer.helloWorldAction.action">helloWorld</a>
</body>
</html>
Copy the codeGo ahead and create success.jsp in that folder
<%@ page language="java" pageEncoding="utf-8" contentType="text/html; charset=utf-8"%>
<%@ taglib uri="/struts-tags" prefix="s"%>
<html>
<head>
<title>My JSP 'index.jsp'Starting page</title> </head> <body> < world > >!!!! <br> </body> </html>Copy the codeThe fourth step is to create the action file. Create the HelloWorldAction class in the SRC directory and implement the Action interface.
public class HelloWorldAction implements Action {
public String execute(a) throws Exception {
System.out.println("HelloWorldAction ...");
return "success"; }}Copy the codeStep five, write the configuration file. Create a struts. XML file in the SRC directory. The name of the file is fixed and cannot be changed.
<! DOCTYPEstruts PUBLIC
"-//Apache Software Foundation// Struts Configuration 2.3//EN"
"http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
<! *name: indicates the name of the package, which is unique and is used to inherit *namespace: namespace, *extends:"struts-default. XML "is also a configuration file provided by the struts2 framework -->
<package name="primer" namespace="/primer" extends="struts-default">
<! -- action tag: indicates the request link *name: the name of the action, which is unique *class: the full path of the action class to be executed -->
<action name="helloWorldAction" class="cn.itcast.action.HelloWorldAction">
<! -- result tag: return the result *name: return the result type, which corresponds to the value returned by the execute() method * The text part after the result tag: the page to go to -->
<result name="success">/success.jsp</result>
</action>
</package>
</struts>
Copy the codeAs a final step, configure the filters in the web.xml file.
<filter>
<filter-name>StrutsPrepareAndExecuteFilter</filter-name>
<filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>StrutsPrepareAndExecuteFilter</filter-name>
<url-pattern>/ *</url-pattern>
</filter-mapping>
Copy the codeThis is the filter provided by Struts2, so the contents of the class tag are fixed. That completes all the steps.
Deploy and run the project.
