Maven构建OSGI+HttpServer应用

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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<Bundle> bundles;static BundleContext getBundleContext() {return bundleContext;}public void start(BundleContext bundleContext) throws Exception {Activator.bundleContext = bundleContext;installBundles(bundleContext, false); // install other bundlesServiceReference 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 bundleshttpService.unregister("/osgi");httpService.unregister("/test");Activator.bundleContext = null;System.out.println("stop ok");}public void installBundles(BundleContext context, boolean uninstall) {List<String> bundleFiles = new LinkedList<String>();List<Bundle> installedBundles = new LinkedList<Bundle>();//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 bundlesfor (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 bundlesfor (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());@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {resp.getWriter().write("MyServlet return: Method=" + req.getMethod() + ", URI=" + req.getRequestURI());}@Overrideprotected 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

<!DOCTYPE html>
<html>
<head><meta charset="UTF-8"><title>jetty test</title>
</head>
<body>
<h2>OSGI HttpServer/Jetty Test</h2>
<font color="green"> register static resource/pages: </font><br>
registerResources(String alias, String name, HttpContext httpContext) <br><br><font color="green">register servlet class: </font><br>
registerServlet(String alias, Servlet servlet, Dictionary initparams, HttpContext httpContext)
</body>
</html>

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：

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><groupId>com.xxx.osgi</groupId><artifactId>osgi-httpserver-demo</artifactId><version>1.0.0-SNAPSHOT</version><packaging>bundle</packaging><name>osgi-httpserver-demo</name><url>http://maven.apache.org</url><properties><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><java.version>1.8</java.version><maven.compiler.source>1.8</maven.compiler.source><maven.compiler.target>1.8</maven.compiler.target></properties><dependencies><dependency><!-- 该版本 maven 仓库找不到，如果要用该版本可以在 Project Structure->Project Settings->Modules 中设置：--><!-- 设置 OSGI:General->Configure OSGI Core Library->Use Library 指定本地 jar 文件静态添加 osgi lib  --><!--<groupId>org.eclipse</groupId><artifactId>osgi</artifactId><version>3.18.600.v20231110-1900</version><scope>provided</scope>--><!-- 该版本maven仓库可以找到，可以用这个版本。在 pom 中指定 osgi lib 的 dependency 依赖 --><groupId>org.eclipse</groupId><artifactId>osgi</artifactId><version>3.10.0-v20140606-1445</version><scope>provided</scope></dependency><!-- START: httpServer required bundles --><!-- org.osgi.service.cm_1.6.1.202109301733.jar --><dependency><groupId>org.osgi</groupId><artifactId>org.osgi.service.cm</artifactId><version>1.6.1</version></dependency><!-- javax.servlet-3.0.0.v201112011016.jar --><dependency><groupId>org.eclipse.jetty.orbit</groupId><artifactId>javax.servlet</artifactId><version>3.0.0.v201112011016</version></dependency><!-- http-1.0.100-v20070423.jar --><dependency><groupId>org.eclipse.equinox</groupId><artifactId>http</artifactId><version>1.0.100-v20070423</version></dependency><!-- org.osgi.service.http-1.2.2.jar --><dependency><groupId>org.osgi</groupId><artifactId>org.osgi.service.http</artifactId><version>1.2.2</version></dependency><!-- END: httpServer required bundles --><!-- for: org.eclipse.core.runtime.FileLocator --><!-- common-3.6.200-v20130402-1505.jar / org.eclipse.equinox.common.source_3.18.200.v20231106-1826.jar --><dependency><groupId>org.eclipse.equinox</groupId><artifactId>common</artifactId><version>3.6.200-v20130402-1505</version></dependency></dependencies><build><plugins><plugin><!-- osgi 打包配置，使用 maven-bundle-plugin 插件进行 osgi 打包 bundle jar --><!-- 使用maven-bundle-plugin打包方式时指定manifest文件不生效，但可在 instructions 中配置 manifest 参数 --><groupId>org.apache.felix</groupId><artifactId>maven-bundle-plugin</artifactId><version>3.5.0</version><extensions>true</extensions><configuration><instructions><!-- 把依赖的普通jar和bundle jar也一起打包进去(/lib目录下)，bundle jar 服务依赖还要在 Import-Package 中指定 --><Embed-Dependency>*;scope=compile|runtime</Embed-Dependency><Embed-Directory>lib</Embed-Directory><Embed-Transitive>true</Embed-Transitive><!-- BEGIN: 把本地静态资源目录也打包进去 --><Include-Resource>webpage=webpage</Include-Resource><!-- END: 把本地静态资源目录webpage也打包进去(到webpage目录、相当于目录拷贝) --><Bundle-ClassPath>.,{maven-dependencies}</Bundle-ClassPath><Bundle-Name>${project.name}</Bundle-Name><Bundle-SymbolicName>$(replace;${project.artifactId};-;_)</Bundle-SymbolicName><Bundle-Version>${project.version}</Bundle-Version><Bundle-Activator>com.xxx.osgi.httpserver.demo.Activator</Bundle-Activator><DynamicImport-Package>*</DynamicImport-Package><Import-Package>javax.servlet,javax.servlet.http,org.osgi.service.http;resolution:="optional"</Import-Package><Export-Package></Export-Package></instructions></configuration></plugin></plugins></build>
</project>

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）：