Contribution:
strutsXml
Intent
Web programming in Language:Java with Technology:Struts configuring with XML
Motivation
This is a simple Struts-based web implementation of the basic 101companies-features. Java annotations are used for redirection rules. Server-side storage or persistence relies on XML an object streams. See Contribution:strutsAnnotation for a similar implementation that uses annotations instead for the redirection rules.
Illustration
The company data is stored in a serialization file. To obtain the stored data, there is an auxiliarly method in the Company class.
public class Company {
...
public static Company readObject(String filename) {
Object o = null;
try {
FileInputStream fis = new FileInputStream(filename);
ObjectInputStream in = new ObjectInputStream(fis);
o = in.readObject();
in.close();
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
return (Company) o;
}
...
Based on the struts2 architecture, the controller layer is implemented by Java classes (action classes) that extend the class ActionSupport and implement the Preparable interface. This approach uses the xworks framework and a simple CRUD design, where only one action is necessary to all operations (edit and cut salaries of a department, edit and cut salaries of an employee, and so on). CompanyAction is the single Action class in this project, with the definition:
public class CompanyAction extends ActionSupport implements Preparable {
...
}
The view layer might be implemented using Java Server Pages (JSPs) or other template languages such as Velocity. Here, we use JSPs to implement the view layer. The listing bellow shows a code fragment of the department.jsp view component. You should notice some special tags such as s:form and s:iterator, which are declared in the Struts tag library. Using theses tags we are able to refer to properties of the action that redirected to the specific view.
...
<h2>Department details</h2>
<s:form action="DEP!save.action" method="post">
<s:textfield name="department.name" value="%{department.name}" label="Name" size="30" />
<s:textfield name="department.manager.person.name" value="%{department.manager.person.name}" label="Manager" size="30" />
<s:textfield name="department.manager.salary" value="%{department.manager.salary}" label="Manager salary" size="15" />
<s:textfield name="department.manager.person.address" value="%{department.manager.person.address}" label="Manager address" size="30" />
<s:textfield value="%{department.total()}" label="Total salaries" readonly="true" size="30" />
<s:hidden name="empName" value="%{department.manager.person.name}" />
<s:hidden name="deptName" value="%{department.name}" />
<s:submit value="Save" />
<s:submit value="Cut" action="cutSalaries"/>
<s:submit value="Company details" action="index" />
</s:form>
<br>
<h2><s:text name="Subdepartments" /></h2>
<table class="outline" border="1" width="50%">
<tr>
<th width="70%"><s:text name="Name" /></th>
<th width="30%">Edit department</th>
</tr>
<s:iterator value="department.subunits" status="status">
<tr>
<s:if test="department">
<td class="nowrap"><s:property value="name" /></td>
<td class="nowrap">
<s:url action="DEP!input" id="link">
<s:param name="department.name" value="name" />
</s:url>
<a href="<s:property value="#link"/>">Detail</a>
</td>
</s:if>
</tr>
</s:iterator>
</table>
...
As explained, an XML file declares which view should be displayed as an action response. For instance, if the cutSalaries action was performed, the system should redirect to one of two components: department.jsp or employee.jsp. This decision depends on the returned value of the corresponding method ( implemented by the CompanyAction class).
public String cutSalaries() {
String redirect = SUCCESS;
if(department != null && deptName != null) {
service.cutDepartmentSalaries(deptName);
redirect = DEPARTMENT SAVE;
}
else if(employee != null && empName != null) {
service.cutEmployeeSalary(empName);
redirect = EMPLOYEE SAVE;
}
return redirect;
}
The struts.xml file informs the next view that should be displayed, depending on the returned value of a call to the cutSalaries method.
<action name="cutSalaries" class="org.softlang.action.CompanyAction" method="cutSalaries">
<result name="department.save">/WEB-INF/jsp/department.jsp</result>
<result name="employee.save">/WEB-INF/jsp/employee.jsp</result>
</action>
Usage
Requirements:
- Technology:Maven (Version 2.x) as Technology:Eclipse plugin (http://eclipse.org/m2e/download/) or standalone (http://maven.apache.org/download.html)
- Web server or application server based on the servlet technology (We recommend JBoss application server, but Technology:Apache Tomcat will also be sufficient).
- Click the "File"-button in the menu bar and "Import...".
- Select the "Maven" folder and "Existing Maven Projects".
- Browse to your local "strutsAnnotation" folder and "Finish".
- Run "mvn clean" and "mvn install" in the root directory of the struts 2 implementation or (Eclipse only) right click on your imported project and first click "Run As" -> "Maven clean" and second "Run As" -> "Maven install".
- Copy the target/struts2app.war file to the web-application folder of your Web server (JBoss application server:
/server/default/deploy).
- Start your Web server (JBoss application server:
/bin/run.bat (Windows) or /bin/run.sh (Unix)). - Start your Web browser and go to http://localhost:8080/struts2app.
Issues
- Potentially simplify Controller/Service; no service object needed
- Add substantial README/code documentation
Language:
Java
Headline
Illustration
Let's show "Hello World" for Java.
public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello, World");
}
}
Contribution:
strutsAnnotation
Headline
Web programming in Language:Java with Technology:Struts configuring with annotations
Motivation
This Language:Java web application illustrates the use of the popular Technology:Struts technology in combination with Technology:JSP and a servlet based web server. It introduces the use of Technology:Maven as a good advantage for Language:Java based applications, as well.
Illustration
The Technology:Struts architecture is based on MVC. The view is implemented with Technology:JSP, the controller is based on Language:Java action classes in combination with servlets and the model is provided by a service class and a class for each company, department and employee. The initial Feature:Hierarchical company data is stored in a serialization file (compare Contribution:javaInheritance). We will illustrate the Technology:Struts implementation with an example of showing and cutting a company.
View
The Technology:JSP file for the view of the company offers two textfields and two buttons. One of the textfields shows the name, the other one shows the Feature:Total value. The buttons allow the user to request for further detailed information like a department list. It also allows her to cut all salaries of the company.
...
<s:form action="company">
...
<s:iterator value="allCompanies">
<tr>
<td><s:property value="name"/></td>
<td><s:property value="total"/></td>
<td>
<s:url id="cutURL" action="company.cutSalaries">
<s:param name="id" value="%{id}"/>
</s:url>
<s:a href="%{cutURL}">Cut</s:a>
</td>
<td>
<s:url id="detailURL" action="company.details">
<s:param name="id" value="%{id}"/>
</s:url>
<s:a href="%{detailURL}">Detail</s:a>
</td>
</tr>
</s:iterator>
...
The iterator
<s:iterator ... />
"allCompanies"
List<Company> allCompanies;
Controller
The
action="company.cutSalaries"
cutSalaries()
@Action(value = "company.cutSalaries",
results = { @Result(name = "listAllCompanies", type="redirectAction", location="list-all-companies")})
public String cutSalaries() {
company = CompanyService.instance().findCompany(Long.parseLong(RequestUtil.getRequestParameter("id")));
company.cut();
return "listAllCompanies";
}
The
@Action(value = "company.cutSalaries", ...)
CompanyService.instance()
results
@Action(value = "company.cutSalaries", ...)
Model
All data are instantiated within the Singleton CompanyService.java, which is considered as a major part of the model. The instance contains lists of the company, its departments and its employees. As we have seen in the controller description, the Feature:Cut method of all of these entities is invokeable. In our case, the cut method for the company simply invokes the cut method of the departments:
public void cut() {
for (Department d : getDepts())
d.cut();
}
The lists within this CompanyService.java are initialized by loading a previously serialized company. We strongly recommend to have a look on Contribution:javaInheritance, to get an overview over the serialization and deserialization process in Language:Java.
Architecture
- The Technology:JSP files for the view are located in this!!src/main/webapp/WEB-INF/content.
- The index.jsp in the this!!src/main/webapp folder represents the initial page, which redirects to the first list-all-companies.jsp. The this!!src/main/webapp folder also contains the Language:CSS files for this application.
- The this!!src/main/resources folder contains two necessary files. The this!!src/main/resources/sampleCompany.ser provides the serialized company data. The this!!src/main/resources/struts.xml Language:XML file defines, that the initial page of this application is the index.jsp.
- The main Language:Java code of the application is located in this!!src/main/java/org/softlang. We have four folders for the different concerns. this!!src/main/java/org/softlang/actions contains the actions described in the illustration section for the controller. The this!!src/main/java/org/softlang/basics folder contains all necessary classes for the deserialized company. The CompanyService.java is located in the this!!src/main/java/org/softlang/services folder. The last folder this!!src/main/java/org/softlang/util contains some helpful Language:Java files for the deserialization.
Usage
Requirements:
- Technology:Maven (Version 2.x) as Technology:Eclipse plugin (http://eclipse.org/m2e/download/) or standalone (http://maven.apache.org/download.html)
- Web server or application server based on the servlet technology (We recommend JBoss application server, but Technology:Apache Tomcat will also be sufficient).
- Click the "File"-button in the menu bar and "Import...".
- Select the "Maven" folder and "Existing Maven Projects".
- Browse to your local "strutsAnnotation" folder and "Finish".
- Run "mvn clean" and "mvn install" in the root directory of the struts 2 implementation or (Eclipse only) right click on your imported project and first click "Run As" -> "Maven clean" and second "Run As" -> "Maven install".
- Copy the target/struts2app.war file to the web-application folder of your Web server (JBoss application server:
/server/default/deploy).
- Start your Web server (JBoss application server:
/bin/run.bat (Windows) or /bin/run.sh (Unix)). - Start your Web browser and go to http://localhost:8080/struts2app.
Contributors
Concept:
Web browser
Concept:
Web programming
Concept:
Web server
Technology:
Apache Tomcat
Technology:
Eclipse
Technology:
Maven
Technology:
Struts
Intent
A Language:Java-based Web-application framework with Technology:JSP and Servlets
Description
Apache Struts is a web-application framework highly dedicated to MVC. It affects every component of MVC, is it the view (Technology:JSP), the controller (Language:Java actions in combination with the Technology:Servlet API) or the model (Java services). Apache Struts supports Ajax as well as REST and SOAP <cite>ApacheStruts2012official</cite>.