Spring Framework Interveiw Questions and Answers: Data Access with Spring and Struts: Part 1

Friday, 5 July 2013

Data Access with Spring and Struts: Part 1

The struts pagination post contained an example of using Hibernate for data access too. In this post, I use the same example to implement the same pagination example using Spring. In this part we will see how to get a struts application ready for spring, the next part describes how to implement data access in spring. Follow these steps to run the example.

Start with the struts-blank application

Create the search.jsp file

<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%>
<%@ taglib uri="http://struts.apache.org/tags-bean" prefix="bean"%>
<%@ taglib uri="http://struts.apache.org/tags-html" prefix="html"%>
<%@ taglib uri="http://struts.apache.org/tags-logic" prefix="logic"%>
<%@ taglib uri="http://displaytag.sf.net" prefix="display"%>
<%@ page import="beans.Employee,business.Sorter,java.util.List,org.displaytag.tags.TableTagParameters,org.displaytag.util.ParamEncoder"%>
<html:html>
<head>
<title>Search page</title>
<link rel="stylesheet" type="text/css"
href="/StrutsPaging/css/screen.css" />
</head>
<body bgcolor="white">
<html:form action="/search.do">
<table>
 <tr>
   <td>Minimum Salary:</td>
   <td><html:text property="minSalary"></html:text></td>
 </tr>
 <tr>
   <td colspan="2"><html:submit property="submit" /></td>
 </tr>
</table>
</html:form>
<logic:notEqual name="empList" value="null">
<jsp:scriptlet>
 if (session.getAttribute("empList") != null) {
   String sortBy = request.getParameter((new ParamEncoder("empTable")).encodeParameterName(TableTagParameters.PARAMETER_SORT));
   Sorter.sort((List) session.getAttribute("empList"), sortBy);
 }
</jsp:scriptlet>

<display:table name="sessionScope.empList" pagesize="4" id="empTable" sort="external" defaultsort="1" defaultorder="ascending" requestURI="">
 <display:column property="empId" title="ID" sortable="true" sortName="empId" headerClass="sortable" />
 <display:column property="empName" title="Name" sortName="empName" sortable="true" headerClass="sortable" />
 <display:column property="empJob" title="Job" sortable="true" sortName="empJob" headerClass="sortable" />
 <display:column property="empSal" title="Salary" sortable="true" headerClass="sortable" sortName="empSal" />
</display:table>
</logic:notEqual>
</body>
</html:html>

pages/search.jsp

Create the Action class:

public class SearchAction extends Action {
private BusinessInterface businessInterface;
public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse httpservletresponse) throws Exception {
 if (form == null) {
   return mapping.findForward("success");
 }
 try {
   SearchForm searchForm = (SearchForm) form;
   if (searchForm.getMinSalary() == null || searchForm.getMinSalary().equals("")) {
     return mapping.findForward("success");
   }
   long minSal = Long.parseLong(searchForm.getMinSalary());
   System.out.println("Business Interface: " + businessInterface);
   List data = businessInterface.getData(minSal);
   System.out.println("Data : " + data);
   request.getSession().setAttribute("empList", data);

 } catch (Exception e) {
   e.printStackTrace();
 }
 return mapping.findForward("success");
}

  public void setBusinessInterface(BusinessInterface bi) {
    businessInterface = bi;
  }
}

SearchAction.java
Note that the action class has a property businessInterface. This property will be set by spring when loading the action class.

Define the form and action beans in struts-config.xml

<form-beans>
<form-bean name="searchForm" type="forms.SearchForm" />
</form-beans>
<action-mappings>
<action path="/Welcome" forward="/pages/Welcome.jsp" />
<action name="searchForm" path="/search" scope="session" type="org.springframework.web.struts.DelegatingActionProxy">
 <forward name="success" path="/pages/search.jsp"></forward>
</action>
</action-mappings>

Note that, in the action-mapping, the action type is defined as "org.springframework.web.struts.DelegatingActionProxy". This will ensure that Spring will take care of handling struts actions.

Integrate Struts And Spring: The final step of integration is to add a spring plugin to struts-config.xml. The plugin defines the location of the spring bean-factory definitions.
```
<plug-in className="org.springframework.web.struts.ContextLoaderPlugIn">
<set-property property="contextConfigLocation"
 value="/WEB-INF/applicationContext.xml"/>
</plug-in>
```
This is one way of integrating struts and spring, for other ways of integration, refer to : Get a better handle on Struts actions, with Spring

Continue to part 2 of "Data access with spring and struts".

Spring Framework Interveiw Questions and Answers

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Friday, 5 July 2013

Data Access with Spring and Struts: Part 1

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