这一节里主要讲解osmp的服务发现与路由。osmp通过osmp-http组件对外发布了一个cxf的restful服务，所有的请求都通过这个restful这个接口接受请求并解析请求后再调用osgi的服务完成请求后返回到前端。
request->osmp-http的restful接口->解析请求->osgi服务发现->服务路由->调用服务->返回-->组装返回参数->返回
osmp通过osmp-service组件来对服务进行统一管理，主要功能包括服务的监听、bundle的监听、服务容器管理、服务注册到zookeeper等功能。
在osgi里可以通过ServiceTracker 服务跟踪器来跟踪某一类接口服务的新增、修改、删除等操作，通过BundlerContext.addBundleListener()注册 bundle监听器（BundleListener）来监听bundle各生命周期的事件，比如bundle的安装、卸载、更新、启动、停止等事件。
osmp为了便于对服务的统一管理，要求所有的服务都必须实现 osmp-intf-define里的定义的BaseDataService接口。这样我们就可以通过服务跟踪器跟踪到BaseDataService接口的服务新增、修改、删除等事件！
具体代码可以参照osmp-service里 ServiceWatcher.java类
/*
* Project: OSMP
* FileName: ServiceWatcher.java
* version: V1.0
*/
package com.osmp.service.watch;
import java.util.Date;
import java.util.UUID;
import org.osgi.framework.BundleContext;
import org.osgi.framework.BundleEvent;
import org.osgi.framework.BundleListener;
import org.osgi.framework.ServiceReference;
import org.osgi.util.tracker.ServiceTracker;
import org.osgi.util.tracker.ServiceTrackerCustomizer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.osgi.context.BundleContextAware;
import org.springframework.util.Assert;
import com.osmp.intf.define.config.FrameConst;
import com.osmp.intf.define.interceptor.ServiceInterceptor;
import com.osmp.intf.define.service.BaseDataService;
import com.osmp.intf.define.service.ZookeeperService;
import com.osmp.service.bean.DataServiceInfo;
import com.osmp.service.bean.InterceptorInfo;
import com.osmp.service.factory.ServiceFactoryImpl;
import com.osmp.service.manager.ServiceStateManager;
import com.osmp.service.registration.ServiceContainer;
import com.osmp.service.util.ServiceUtil;
import com.osmp.utils.net.RequestInfoHelper;
/**
*
* Description:服务注册、注销、监听
* @author: wangkaiping
* @date: 2016年8月9日 上午10:27:15上午10:51:30
*/
public class ServiceWatcher implements BundleContextAware, InitializingBean, DisposableBean {
private Logger logger = LoggerFactory.getLogger(ServiceWatcher.class);
private ServiceTracker dataServiceTracker;
private ServiceTracker serviceInterceptorTracker;
private ServiceStateManager serviceStateManager;
private ServiceFactoryImpl serviceFactoryImpl;
private BundleContext context;
private ZookeeperService zookeeper;
private final static String NODE_CHANGE = "/osmp/nodechange";
@Override
public void setBundleContext(BundleContext context) {
this.context = context;
}
public void setServiceFactoryImpl(ServiceFactoryImpl serviceFactoryImpl) {
this.serviceFactoryImpl = serviceFactoryImpl;
}
public void setServiceStateManager(ServiceStateManager serviceStateManager) {
this.serviceStateManager = serviceStateManager;
}
public void setZookeeper(ZookeeperService zookeeper) {
this.zookeeper = zookeeper;
}
@Override
public void destroy() throws Exception {
if (dataServiceTracker != null) {
dataServiceTracker.close();
}
if (serviceInterceptorTracker != null) {
serviceInterceptorTracker.close();
}
logger.info("服务监听结束");
}
@Override
public void afterPropertiesSet() throws Exception {
Assert.notNull(context);
Assert.notNull(serviceStateManager);
Assert.notNull(serviceFactoryImpl);
dataServiceTracker = new ServiceTracker(context, BaseDataService.class.getName(),
new DataServiceTrackerCustomizer());
serviceInterceptorTracker = new ServiceTracker(context, ServiceInterceptor.class.getName(),
new ServiceInterceptorTrackerCustomizer());
dataServiceTracker.open(true);
serviceInterceptorTracker.open(true);
context.addBundleListener(new BundleListener() {
@Override
public void bundleChanged(BundleEvent event) {
if (event.getType() == BundleEvent.UNINSTALLED) {
String name = event.getBundle().getSymbolicName();
try {
logger.info("uninstall bundle " + name);
zookeeper.deleteNodeByBundle(name);
ServiceWatcher.this.nodeUpdate();
} catch (Exception e) {
logger.error(
"zookeeper delete service by bundle, bundle name : "
+ name, e);
}
}
}
});
logger.info("服务监听启动");
}
// dataService监听
private class DataServiceTrackerCustomizer implements ServiceTrackerCustomizer {
@Override
public Object addingService(ServiceReference reference) {
BaseDataService bsService = (BaseDataService) context.getService(reference);
String bundleName = reference.getBundle().getSymbolicName();
String bundleVersion = reference.getBundle().getVersion().toString();
Object name = reference.getProperty(FrameConst.SERVICE_NAME);
if (name == null || "".equals(name)) {
logger.error("组件" + bundleName + "(" + bundleVersion
+ ") dataService服务name未设置");
return bsService;
}
Object mark = reference.getProperty(FrameConst.SERVICE_MARK);
ServiceContainer.getInstance().putDataService(bundleName, bundleVersion, name.toString(), bsService);
DataServiceInfo info = new DataServiceInfo();
info.setBundle(bundleName);
info.setVersion(bundleVersion);
info.setName(name.toString());
info.setState(1);
info.setUpdateTime(new Date());
info.setMark(mark == null ? "" : mark.toString());
serviceStateManager.updateDataService(info);
String path = ZookeeperService.ROOT_PATH
+ ZookeeperService.SERVICE + "/"
+ RequestInfoHelper.getLocalIp() + "/";
logger.debug("register service path: " + path + " bundle : " + bundleName + " to zookeeper ");
ServiceWatcher.this.registerService(path, info);
return bsService;
}
@Override
public void modifiedService(ServiceReference reference, Object service) {
}
@Override
public void removedService(ServiceReference reference, Object service) {
String bundleName = reference.getBundle().getSymbolicName();
String bundleVersion = reference.getBundle().getVersion()
.toString();
Object name = reference.getProperty(FrameConst.SERVICE_NAME);
if (name == null || "".equals(name)) {
logger.error("组件" + bundleName + "(" + bundleVersion
+ ") dataService服务name未设置");
return;
}
ServiceContainer.getInstance().removeDataService(bundleName, bundleVersion, name.toString());
Object mark = reference.getProperty(FrameConst.SERVICE_MARK);
DataServiceInfo info = new DataServiceInfo();
info.setBundle(bundleName);
info.setVersion(bundleVersion);
info.setName(name.toString());
info.setState(0);
info.setMark(mark == null ? "" : mark.toString());
info.setUpdateTime(new Date());
serviceStateManager.updateDataService(info);
System.out.println("===============remove service bundleName:"
+ bundleName + " name: " + name.toString() + " mark: "
+ mark.toString());
String path = ZookeeperService.ROOT_PATH
+ ZookeeperService.SERVICE + "/"
+ RequestInfoHelper.getLocalIp() + "/";
ServiceWatcher.this.unRegisterService(path, info);
}
}
// ServiceInterceptor监听
private class ServiceInterceptorTrackerCustomizer implements ServiceTrackerCustomizer {
@Override
public Object addingService(ServiceReference reference) {
ServiceInterceptor sicpt = (ServiceInterceptor) context.getService(reference);
String bundleName = reference.getBundle().getSymbolicName();
String bundleVersion = reference.getBundle().getVersion().toString();
Object name = reference.getProperty(FrameConst.SERVICE_NAME);
if (name == null || "".equals(name)) {
logger.error("组件" + bundleName + "(" + bundleVersion
+ ") serviceInterceptor服务name未设置");
return sicpt;
}
Object mark = reference.getProperty(FrameConst.SERVICE_MARK);
ServiceContainer.getInstance().putInterceptor(
ServiceUtil.generateServiceName(bundleName, bundleVersion, name.toString()), sicpt);
InterceptorInfo info = new InterceptorInfo();
info.setBundle(bundleName);
info.setVersion(bundleVersion);
info.setName(name.toString());
info.setState(1);
info.setUpdateTime(new Date());
info.setMark(mark == null ? "" : mark.toString());
serviceStateManager.updateServiceInterceptor(info);
return sicpt;
}
@Override
public void modifiedService(ServiceReference reference, Object service) {
}
@Override
public void removedService(ServiceReference reference, Object service) {
String bundleName = reference.getBundle().getSymbolicName();
String bundleVersion = reference.getBundle().getVersion().toString();
Object name = reference.getProperty(FrameConst.SERVICE_NAME);
if (name == null || "".equals(name)) {
logger.error("组件" + bundleName + "(" + bundleVersion
+ ") serviceInterceptor服务name未设置");
return;
}
Object mark = reference.getProperty(FrameConst.SERVICE_MARK);
ServiceContainer.getInstance().removeInterceptor(
ServiceUtil.generateServiceName(bundleName, bundleVersion, name.toString()));
InterceptorInfo info = new InterceptorInfo();
info.setBundle(bundleName);
info.setVersion(bundleVersion);
info.setName(name.toString());
info.setState(0);
info.setMark(mark == null ? "" : mark.toString());
info.setUpdateTime(new Date());
serviceStateManager.updateServiceInterceptor(info);
}
}
/**
* 向zookeeper注册服务
*
* @param path
* @param ds
*/
public void registerService(String path, DataServiceInfo ds) {
String bundle = ds.getBundle();
String cname = ds.getMark();
String name = ds.getName();
String version = ds.getVersion();
String status = String.valueOf(ds.getState());
try {
if (!zookeeper.exists(path + name)) {
zookeeper.createNode(path + name);
}
if (!zookeeper.exists(path + name + "/bundle")) {
zookeeper.createNode(path + name + "/bundle", bundle);
} else {
zookeeper.setNodeData(path + name + "/bundle", bundle);
}
if (!zookeeper.exists(path + name + "/cname")) {
zookeeper.createNode(path + name + "/cname", cname);
} else {
zookeeper.setNodeData(path + name + "/cname", cname);
}
if (!zookeeper.exists(path + name + "/version")) {
zookeeper.createNode(path + name + "/version", version);
} else {
zookeeper.setNodeData(path + name + "/version", version);
}
if (!zookeeper.exists(path + name + "/status")) {
zookeeper.createNode(path + name + "/status", status);
} else {
zookeeper.setNodeData(path + name + "/status", status);
}
this.nodeUpdate();
} catch (Exception e) {
e.printStackTrace();
logger.error("zookeeper register service fail, service name : "
+ name, e);
}
}
/**
* 卸载服务
*
* @param path
* @param ds
*/
public void unRegisterService(String path, DataServiceInfo ds) {
String name = ds.getName();
try {
if (zookeeper.exists(path + name + "/status")) {
zookeeper.setNodeData(path + name + "/status",
String.valueOf(ds.getState()));
this.nodeUpdate();
}
} catch (Exception e) {
e.printStackTrace();
logger.error("zookeeper unRegister service fail, service name : "
+ name, e);
}
}
/**
* 更新节点状态变化
*/
public void nodeUpdate(){
String data = UUID.randomUUID().toString();
try {
if(zookeeper.exists(NODE_CHANGE)){
zookeeper.setNodeData(NODE_CHANGE, data);
}else{
zookeeper.createNode(NODE_CHANGE);
zookeeper.setNodeData(NODE_CHANGE, data);
}
} catch (Exception e) {
logger.error("更新节点变化状态错误", e);
}
}
}
- ServiceWatcher 实现 BundleContextAware接口，将BundleContext 设置进来。
- 在ServiceWatcher初始化的时候 实例化了两个服务跟踪器 （ServiceTracker）分别用来跟踪 BaseDataService、ServiceInterceptor 两类接口的服务。
- 在ServiceWatcher初始化的时候 给BundleContext新增Bunlde监听用来监听bundle的事件
- ServiceTracker需要传递一个ServiceTrackerCustomizer实例来具体执行监听的事件，在这里我们通过DataServiceTrackerCustomizer来具体执行BaseDataService接口服务跟踪操作。
- 当BaseDataService 服务被发布到osgi容器里的时候，会自动调用DataServiceTrackerCustomizer.addingService(ServiceReference reference) 方法，通过BundleContext.getService(ServiceReference reference),我们可以获取到当前被发布到osgi容器里的服务。
- 通过获取bundleName、bundleVersion、以前发布服务时定义的tag标签（name）组成唯一的key(bundleName+bundleVersion+name) 以获取到service为value。将此保存到服务容器（Map）里。
注：osmp-service里将监听到的服务同时保存到数据库里和注册到zookeeper请暂时忽略，稍后osmp注册中会作详细讲解。
服务发现和路由：
osmp-http接收到请求后解析服务名称，通过服务查询此服务是否绑定了拦截器，如果绑定了拦截器，则先执行拦截器链，拦截器如果执行失败则直接返回，如果拦截器执行成功则通过服务名称获取服务，获取服务成功后直接执行服务的execute方法，将并结果返回！
这里讲的简单点儿，具体osmp封装了一层代理实现，有兴趣的可以直接查看osmp-http源码。
至此osmp的服务发现和服务调用功能就讲到这里！
相关推荐
《 OSGi实战》是学习OSGi的全面指导，利用与架构和开发人员相关的示例清楚地讲解OSGi概念，同时探讨了很多实践场景和技术，阐述了开发人员有多需要OSGi，怎么将OSGi嵌入其他容器中，将遗留系统移入OSGi的最佳实践，...
文内难免有些错误,还请大家不吝指正,也希望本文能作为国内 OSGI 的抛砖之作,引出更多的关于 OSGI的 Opendoc,在我的 blog 上也会不断的编写关于自己在 OSGI、Equinox 上的实战的体会和心得,欢迎大家多多交流。
为了弥补OSGi规范在应用指导方面的不足，四位活跃在OSGi开发第一线的技术专家联手打造了《OSGi实战》。《OSGi实战》面向OSGi规范的使用者，系统、全面、深入地阐述OSGi的重要特性及其使用方法。《OSGi实战》还介绍了...
osgi，林昊写的osgi实战和进阶，学习osgi的好东西，入门的首选。
资源名称：OSGi实战内容简介：为了弥补OSGi规范在应用指导方面的不足，四位活跃在OSGi开发第一线的技术专家联手打造了《OSGi实战》。《OSGi实战》面向OSGi规范的使用者，系统、全面、深入地阐述OSGi的重要特性及其...
网上收集的OSGI资料. 包括： OSGi原理与最佳实践（精选版）.pdf OSGI实战和源码.rar osgi进阶.pdf Introduce.OSGi.ppt OSGi.in.action.ppt r4.cmpn.pdf r4.core.pdf r4.enterprise.pdf
OSGI入门和整合Spring + OSGI进阶 + OSGI实战
OSGI实战教程，从需求实现以及技术角度两方面来体验OSGI。
OSGI原理与最佳实践的完整版，共12章 第1 章OSGi 简介 第2 章OSGi 框架简介 第3 章基于Spring-DM 实现Petstore 第4 章基于Apache CXF 实现分布式Petstore 第5 章构建OSGI Bundle Repositor'y 第6 章OSGi 规范解读 ...
java OSGI实战
OSGI进阶.pdf,OSGI实战.pdf,OSGI入门和整合Spring.pdf
BlueDavy的OSGI实战和OSGI进阶两个开源文档，学习OSGI不错的资料
资源名称：OSGI原理与最佳实践内容简介：国内第一本OSGi图书OSGi国内推广者林昊多年经验的结晶涵盖OSGi从入门到深入的知识体系引领OSGi国内研究和普及本书基于作者多年使用OSGi的经验而编写，涵盖了OSGi从入门到深入...
OSGI实战.pdfOSGI实战.pdfOSGI实战.pdfOSGI实战.pdfOSGI实战.pdf
OSGI框架实战 一. 序..5 二. 体验OSGI..7 2.1. 需求实现..7 2.2. 技术角度..9 三. OSGI带来什么..11 四. OSGI案例..13 五. OSGI框架..15 5.1. Equinox..15 5.2. Oscar..15 5.3. Knopflerfish..15 六. 基于OSGI框架...
OSGI实战及源码
OSGI实战中文版。
OSGI实战.pdf
osgi实战源码 通过一个完整购物车实例来展示OSGI的实现.代码简单易懂,可扩展.