Maven构建OSGI+HttpServer应用

Maven构建OSGI+HttpServer应用

官网（https://eclipse.dev/equinox/server/http_in_equinox.php）介绍有两种方式：

一种是基于”org.eclipse.equinox.http”包的轻量级实现，另一种是基于”org.eclipse.equinox.http.jetty”包（基于jetty的Servlet）实现。

使用 "org.eclipse.equinox.http" 包（例如：http-1.0.100-v20070423.jar），可以将我们自定义的服务（servlet或静态资源页面）注册到这个 HttpService 中去，实现自定义的HTTP服务。

"org.osgi.service.http" 包（例如：org.osgi.service.http-1.2.2.jar）内部会内嵌一个 HttpService Interface，而"org.eclipse.equinox.http" 包（http-1.0.100-v20070423.jar）提供了一个上述Interface的 HttpService实现类，因此，一旦这个osgi bundle （http-1.0.100-v20070423.jar）启动了，就会有一个内嵌的 http 服务被启动，默认地址是 http://localhost，端口为 80，可以通过指定参数 “org.osgi.service.http.port”来修改默认端口。

"org.eclipse.equinox.http" 包（http-1.0.100-v20070423.jar）内有一个上面那个 HttpService Interface 的实现类：

想要提供我们自定义的 HttpService服务，就要将我们的服务（servlet或静态资源页面）注册到这个 HttpService 中去，需要用到 "org.osgi.service.http" 包中的 HttpService 类的两个注册方法：

1）注册静态资源：
registerResources(String alias, String name, HttpContext httpContext)

2）注册 Servlet 类：
registerServlet(String alias, Servlet servlet, Dictionary initparams, HttpContext httpContext)

所以要想提供我自己的WebService实现，我们就需要：

提供自定义的WebService实现的步骤如下：
1）获取 httpService 对象；
2）编码提供 servlet 和 webpage 的实现；
3）将 servlet 和 webpage 注册到 HttpService 服务中去（同时指定对应的 alias）；
4）访问；

新建manve项目：

创建package、class、和编码：
1）Java package：com.xxx.osgi.httpserver.demo、com.xxx.osgi.httpserver.servlet
2）Java class文件：Activator.java、MyServlet.java

Activator.java：

package com.xxx.osgi.httpserver.demo;

import com.xxx.osgi.httpserver.servlet.MyServlet;
import org.osgi.framework.Bundle;
import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;
import org.osgi.framework.BundleException;
import org.osgi.framework.ServiceReference;
import org.osgi.service.http.HttpContext;
import org.osgi.service.http.HttpService;

import java.util.LinkedList;
import java.util.List;

/**
 * @author Frank
 * @date 2023/12/26
 */
public class Activator implements BundleActivator {
    private static BundleContext bundleContext;
    private HttpService httpService;
    private List bundles;
   
    static BundleContext getBundleContext() {
        return bundleContext;
    }

    public void start(BundleContext bundleContext) throws Exception {
        Activator.bundleContext = bundleContext;
        installBundles(bundleContext, false); // install other bundles
        ServiceReference serviceReference = bundleContext.getServiceReference(HttpService.class.getName());
        httpService = (HttpService) bundleContext.getService(serviceReference);

        // 注册
        HttpContext httpContext = httpService.createDefaultHttpContext();

        // 注册静态页面，设置别名"/osgi"，所有对"/osgi"的请求映射到"/webpage/index.html"
        httpService.registerResources("/osgi", "/webpage/index.html", httpContext);
        System.out.println("start ok");

        // 注册 servlet，设置servlet别名"/test"，所有对'/test"的请求映射到myServlet的实现
        MyServlet myServlet = new MyServlet();
        httpService.registerServlet("/test", myServlet, null, httpContext);
    }

    public void stop(BundleContext bundleContext) throws Exception {
        installBundles(bundleContext, true); //uninstall other bundles
        httpService.unregister("/osgi");
        httpService.unregister("/test");
        Activator.bundleContext = null;
        System.out.println("stop ok");
    }

    public void installBundles(BundleContext context, boolean uninstall) {
        List bundleFiles = new LinkedList();
        List installedBundles = new LinkedList();
        //install my other bundles
        // System.out.printf("1 %s\n", FileLocator.getBundleFile(FrameworkUtil.getBundle(Activator.class)).getAbsolutePath());
        // System.out.printf("2 %s\n", FileLocator.getBundleFile(context.getBundle()).getAbsolutePath());
        // System.out.printf("3 %s\n", context.getBundle().getLocation());

        // String baseDir = FileLocator.getBundleFile(context.getBundle()).getParentFile().getAbsolutePath();
        String baseDir = context.getBundle().getLocation().replaceFirst("/[^/]*.jar","/");
        bundleFiles.add(baseDir + "helloworld-server-1.0.0-SNAPSHOT.jar");
        if (!uninstall) {
            // install & start bundles
            for (String bundleFile : bundleFiles) {
                try {
                    Bundle bundle = context.installBundle(bundleFile);
                    installedBundles.add(bundle);
                    bundle.start();
                } catch (BundleException e) {
                    if (!e.getMessage().contains("A bundle is already installed")) {
                        throw new RuntimeException(e);
                    }
                }
            }
            bundles = installedBundles;
            System.out.printf("all bundles (cnt = %d) installed and started!", bundles.size());
        } else {
            // stop & uninstall bundles
            for (Bundle bundle : bundles) {
                try {
                    context.getBundle(bundle.getBundleId()).stop();
                    context.getBundle(bundle.getBundleId()).uninstall();
                } catch (BundleException e) {
                    throw new RuntimeException(e);
                }
            }
            System.out.printf("all bundles (cnt = %d) stopped and uninstalled!", bundles.size());
        }
    }
}

MyServlet.java：

package com.xxx.osgi.httpserver.servlet;

import javax.servlet.Servlet;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.logging.Logger;

public class MyServlet extends HttpServlet implements Servlet {
    
    private Logger logger = Logger.getLogger(this.getClass().getName());

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.getWriter().write("MyServlet return: Method=" + req.getMethod() + ", URI=" + req.getRequestURI());
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.getWriter().write("MyServlet return: Method=" + req.getMethod() + ", URI=" + req.getRequestURI());
    }
}

3）创建静态页面文件：webpage/index.html

    
    


OSGI HttpServer/Jetty Test
 register static resource/pages: 

registerResources(String alias, String name, HttpContext httpContext) 



register servlet class: 

registerServlet(String alias, Servlet servlet, Dictionary initparams, HttpContext httpContext)

4）创建&编辑 pom.xml 文件

pom文件中定义了OSGI框架和版本、编码中所需的依赖以及osgi menifest和osgi打包配置：

  4.0.0

  com.xxx.osgi
  osgi-httpserver-demo
  1.0.0-SNAPSHOT
  bundle

  osgi-httpserver-demo
  http://maven.apache.org

  
    UTF-8
    1.8
    1.8
    1.8
  

  

    
      
      
      
      
      org.eclipse
      osgi
      3.10.0-v20140606-1445
      provided
    

    
    
    
      org.osgi
      org.osgi.service.cm
      1.6.1
    
    
    
      org.eclipse.jetty.orbit
      javax.servlet
      3.0.0.v201112011016
    
    
    
      org.eclipse.equinox
      http
      1.0.100-v20070423
    
    
    
      org.osgi
      org.osgi.service.http
      1.2.2
    
    

    
    
    
      org.eclipse.equinox
      common
      3.6.200-v20130402-1505
    

  

  
    
      
        
        
        org.apache.felix
        maven-bundle-plugin
        3.5.0
        true

        
          
            
            *;scope=compile|runtime
            lib
            true

            
            webpage=webpage
            

            .,{maven-dependencies}
            ${project.name}
            $(replace;${project.artifactId};-;_)
            ${project.version}
            com.xxx.osgi.httpserver.demo.Activator
            *
            
              javax.servlet,
              javax.servlet.http,
              org.osgi.service.http;resolution:="optional"
            
            
          
        

      
    
  

整体项目的代码结构如下：

准备运行依赖的bundles：

org.osgi.service.cm_1.6.1.202109301733.jar
javax.servlet-3.0.0.v201112011016.jar
org.osgi.service.http-1.2.2.jar
http-1.0.100-v20070423.jar
 

直接在 configuration/config.ini 初始化启动配置中加入依赖 bundles 或者启动 osgi 以后执行 install 安装依赖 bundles：
install plugins/org.osgi.service.cm_1.6.1.202109301733.jar
install other_bundles/javax.servlet-3.0.0.v201112011016.jar
install other_bundles/org.osgi.service.http-1.2.2.jar
install other_bundles/http-1.0.100-v20070423.jar
start 5 6 7 8 

注意，多条命名install时有先后顺序依赖，也可以放在一条命令执行多个 bundle 的install（无顺序依赖）
install plugins/org.osgi.service.cm_1.6.1.202109301733.jar other_bundles/javax.servlet-3.0.0.v201112011016.jar other_bundles/org.osgi.service.http-1.2.2.jar other_bundles/http-1.0.100-v20070423.jar
 

“org.osgi.service.http”的HttpService Interface的实现类bundle “org.eclipse.equinox.http”启动后，HttpService服务就启动了、查看HttpService监听端口已开启（如果equinox的配置文件或启动参数没有指定 org.osgi.service.http.port=8080 的话，默认是监听的是 80 端口）：

项目编译打包：
执行命令打包
mvn clean package

拷贝项目编译打包生成的jar文件到osgi运行环境：

执行osgi-httpserver-demo jar包（install & start）：

项目bundle 9已经启动、bundle9内代码install & start 的其他bundel 10 也都start成功，状态为ACTIVE了。

httpServer 访问测试（访问 localhost:8080/osgi 和 localhost:8080/test）：
命令行访问页面：

浏览器访问页面：