Bridge Way Construction Method
A Install Eclipse,jdk,tomcat. This paper takes eclipse3.7.2,jdk1.7.0,tomcat-7.0.27 as an example
Lab environment: Win7 X64 Home Premium Edition
Two We need to configure our Tomcat in Eclipse preferences
Select runtime environment in the server
Note (If you don't have a server tag, make sure your ecplise has a Web dev plugin installed)
Point add
Click Next
Select a good tomcat directory and click Finish to complete the configuration.
Three Create a new Plug-project
We named the new Project Com.sample.web, and in the project properties setting, we set the project's run target to Equinox
In the next property setting, we do not choose to create the Activator, as shown in the following figure. Other options remain default
To this we have completed the creation of the entire project, after the creation of the project structure diagram
Four Now we add some real code to our project to facilitate testing
New Package Com.sample.web.servlet under SRC
Create a new folder Webroot in your project and create a new IMG and JSP folder under Webroot
And put in the relevant files
Last directory structure as shown in figure
and create a new file in the package Loginservlet.java (code below):
Package com.sample.web.servlet;
import java.io.ioexception; import java.io.printwriter; import javax.servlet.servletexception; import javax.servlet.http.httpservlet; import
javax.servlet.http.httpservletrequest; import javax.servlet.http.httpservletresponse; /** * @authorLevin * @time2009 -5-29 */ public class Loginservlet extends httpservlet{ public void doget (HttpServletRequest request, H Ttpservletresponse response) throws IOException, servletexception { //web Development Scenario One: Use the Request object to get the client request data string UserName = Request.getparameter ("UserName"); //web Development Scenario II: Operation
session request.getsession (). SetAttribute ("Userfroma", UserName); //web Development Scenario Three: using Response to return response.setcharacterencoding ("GBK"); response.setcontenttype ("text/html"); PrintWriter out = Response.getwriter (); out.println ("
The project will have compile errors because we are using the classes in the Javax.servlet package, so we click on the error message and Eclipse will automatically help us to modify the project's MANIFEST.MF file and add the required package to the import-package. Below is the content of the index.jsp file in our project
<HTML> <HEAD> <title>my App home</title> <meta http-equiv= Content-typecontent= "text/html; Charset=iso-8859-1 "> <% String javaversion = System.getproperty (" java.version "); %> </HEAD> <BODY> <p>current JRE version: <font color= "#FF0000" ><%= javaversion%></font></p> <p> <a href= "/servlet/myfirstservlet?username=usera" > Click to test seervlet </a> </BODY>
the contents of the Plugin.xml file are as follows, where we define two extension points, one to handle requests for resource files such as picture files, and another to handle JSP and Servlet requests.
<?xml version= "1.0" encoding= "UTF-8"?> <?eclipse version= "3.4"?> <plugin> < Extension point= "org.eclipse.equinox.http.registry.resources" > <resource alias= "/images" Base-name= "/webroot/img" > </resource> </extension> <extension point= " Org.eclipse.equinox.http.registry.servlets "> <servlet alias="/servlet/myfirstservlet " class= "Com.sample.web.servlet.LoginServlet" load-on-startup= "true" > </servlet> < servlet alias= "/jsp/*.jsp" class= "org.eclipse.equinox.jsp.jasper.registry.jspfactory:/webroot/jsp/" > </servlet> </extension>
Through the configuration of the extension point, we also need to MANIFEST. The MF file is modified to introduce the required bundles and package. The final MANIFEST. MF file is as follows:
bundle-manifestversion
Bundle-name
Bundle-symbolicname
bundle-version
Bundle-vendor
bundle-requiredexecutionenvironment
Import-package
Require-bundle
Five
The last configuration. Open the project's Run Configuration window, first uncheck all target platform, then tick com.sample.web and then click the Add Required Bundles button. This way, Eclipse does not start all bundles at runtime, but only selectively launches the bundles we configure in the configuration file.
Click Run results as shown
Input SS
We can see that our bundle has been activated.
Now that our WEB application based on Equinox has been completed, the next step is to deploy the Equinox and bundle as a war into the servlet container, just like we used to do in normal web development, as a normal Web application. In this way, a technique called the servlet Bridge is used, and the user's HTTP request to the Web application is forwarded by the Servlet container to the Web application, and the Equinox framework runs in the Web application, uniformly processing the application's Request and forward the request to the corresponding bundle.
Six. In general, the first need to download the Bridge.war file to the Equinox site, this file is the April 2007 version. When we created the project earlier, we did not let anyone choose to create activator, because some of the classes referenced by Activator did not exist in this version of Bridge.war. Also: In our sample project, we need to support JSP, so we need a few additional bundles. For the convenience of everyone, I have also made a Bridge.war, which contains the necessary bundles. In SourceCode. In zip
We're going to import it into our Eclipse workspace,
Seven Next, we export the sample project we just created as a bundle: Open the Build.proerties file for our sample project, and select the Webroot folder and its subfolders and plugin.xml that we need.
It is then exported to deployable plug-ins and fragments
Other by default, you will see that Eclipse will generate the Plugins/com.sample.web_1.0.0.jar file in the directory you specified, and place the jar file under the Plugins folder of the bridge project you just imported
Eight Then put the jar into the bridge project just imported plugins under the specific directory structure as shown
Nine In this way, we do not need to run our sample project, but instead run our bridge project, select Bridge Project, right-->run as->run on server to run the bridge project to our configured TOMCA T to go in. Since we are not set up to let our sample project start automatically by default, everyone here needs to start the bundle of our sample project. Start
Ten Start bundle
Enter SS to view bundle IDs. Suppose id=5
Enter start 5; start the bundle
Now you can access our bundles by entering the URL.
Http://localhost:8080/bridge/servlet/myfirstservlet?userName=Levin
http://localhost:8080/bridge/jsp/index.jsp
Http://localhost:8080/bridge/images/1.jpg
PostScript: In the actual development process, if each time we need to export our project into a jar file to put in bridge, the development efficiency is very low. The above steps are only needed when the project has been developed and actually deployed to the server. In our development process, we can take the following approaches to simplify development:
Open the Webcontent/web-inf/eclipse/configuration/config.ini file for the bridge project and add a reference to our sample project in its osgi.bundles configuration, for example:
Reference\:file\:D:/eclipse-jee-ganymede-sr2-win32/workspace/com.sample.web@start
If we select Bridge project and right-->run as->run on server to run the bridge project into our configured Tomcat, bridge will automatically use our SA in accordance with the configuration in Config.ini Mple project also starts as a bundle.
The above content is excerpt from http://www.ibm.com/developerworks/cn/web/0907_osgiweb_liuqing/
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