OSGI CM之ManagedServiceFactory的使用

OSGI里面用于操作配置文件（cfg）的接口有2个

org.osgi.service.cm.ManagedService  用于操作单个配置文件  用法见  OSGI CM之ManagedService的使用

org.osgi.service.cm.ManagedServiceFactory  用于操作一组相关的配置文件

org.osgi.service.cm.ManagedServiceFactory是一个接口，实现这个接口后，就可以创建一组相关的服务

下面，就举例说明它的使用方法，这里举例说明创建javax.sql.DataSource的例子

首先，加入依赖

<dependency><groupId>org.osgi</groupId><artifactId>org.osgi.core</artifactId><version>5.0.0</version></dependency><dependency><groupId>org.osgi</groupId><artifactId>org.osgi.compendium</artifactId><version>5.0.0</version></dependency><dependency><groupId>org.apache.commons</groupId><artifactId>commons-dbcp2</artifactId><version>2.1.1</version></dependency> 

一：写一个类DataSourceServiceFactory实现ManagedServiceFactory接口，用于创建javax.sql.DataSource服务

package com.lala.service;import java.util.Dictionary;import java.util.Hashtable;import java.util.Map;import java.util.concurrent.ConcurrentHashMap;import javax.sql.DataSource;import org.apache.commons.dbcp2.BasicDataSource;import org.osgi.framework.BundleContext;import org.osgi.framework.ServiceRegistration;import org.osgi.service.cm.ConfigurationException;import org.osgi.service.cm.ManagedServiceFactory;public class DataSourceServiceFactory implements ManagedServiceFactory {private static final String KEY_ID = "DataSourceInstanceId";private BundleContext bundleContext;private Map<String, ServiceRegistration<DataSource>> dsMap = new ConcurrentHashMap<>();public DataSourceServiceFactory(BundleContext bundleContext) {this.bundleContext = bundleContext;}public String getName() {return "DataSourceServiceFactory";}/** * 当有新的配置文件产生时，就会触发 */public void updated(String pid, Dictionary<String, ?> properties) throws ConfigurationException {if(properties == null || properties.isEmpty()) {return;}System.out.println("updated pid : " + pid);ServiceRegistration<DataSource> registration = null;DataSource ds = null;try {ds = createDataSource(properties);} catch (Exception e) {e.printStackTrace();return;}Dictionary<String, String> props = new Hashtable<>();props.put(KEY_ID, getStrVal(properties, "id", null));registration = bundleContext.registerService(DataSource.class, ds, props);dsMap.put(pid, registration);}/** * 当文件被删除（移走）后，会触发 */public void deleted(String pid) {System.out.println("deleted pid : " + pid);ServiceRegistration<DataSource> registration = dsMap.get(pid);if(registration != null){registration.unregister();dsMap.remove(pid);}}private DataSource createDataSource(Dictionary<String, ?> properties) throws Exception {BasicDataSource ds = new BasicDataSource();ds.setUsername(getStrVal(properties, "username", null));ds.setPassword(getStrVal(properties, "password", null));ds.setDriverClassName(getStrVal(properties, "driverClassName", null));ds.setUrl(getStrVal(properties, "url", null));ds.setInitialSize(getIntVal(properties, "initialSize", 5));ds.setMaxIdle(getIntVal(properties, "maxIdle", 5));ds.setMaxTotal(getIntVal(properties, "maxTotal", 5));ds.setMinIdle(getIntVal(properties, "minIdle", 5));return ds;}private String getStrVal(Dictionary<String, ?> properties, String key, String defaultValue) {Object value = properties.get(key);if (value != null) {return value.toString();}return defaultValue;}private Integer getIntVal(Dictionary<String, ?> properties, String key, Integer defaultValue) {String value = getStrVal(properties, key, null);if (value != null) {return Integer.valueOf(value);}return defaultValue;}}

二：在BundleActivator里面注册上一步的ManagedServiceFactory服务

package com.lala.service;import java.util.Dictionary;import java.util.Hashtable;import org.osgi.framework.BundleActivator;import org.osgi.framework.BundleContext;import org.osgi.framework.ServiceRegistration;import org.osgi.service.cm.ManagedServiceFactory;public class ManagedServiceFactoryActivator implements BundleActivator {private static final String SERVICE_PID = "com.lala.service.datasource";private ServiceRegistration<ManagedServiceFactory> registration = null;public void start(BundleContext context) throws Exception {Dictionary<String, String> props = new Hashtable<>();props.put("service.pid", SERVICE_PID);context.registerService(ManagedServiceFactory.class, new DataSourceServiceFactory(context), props);}public void stop(BundleContext context) throws Exception {if(registration != null) {registration.unregister();}}}

注意这里的SERVICE_PID的值，下面要用到

三，在pom.xml里面加入

<build><plugins><plugin><groupId>org.apache.felix</groupId><artifactId>maven-bundle-plugin</artifactId><version>3.0.0</version><extensions>true</extensions><configuration><instructions><Bundle-Activator>com.lala.service.ManagedServiceFactoryActivator</Bundle-Activator></instructions></configuration></plugin></plugins></build>

四：打包好jar之后，就需要运行了，我这里的运行环境为apache-karaf-4.0.3

启动apache-karaf-4.0.3之后，需要先安装commons-dbcp2、commons-pool2（上面的创建javax.sql.DataSource，用到了dbcp，而dbcp又用到了pool）

install -s mvn:org.apache.commons/commons-pool2/2.4.2

install -s mvn:org.apache.commons/commons-dbcp2/2.1.1

OK，安装好之后，就把上面打包好的jar，扔到karaf的deploy目录中去

五：接下来，我们就需要用到上面的SERVICE_PID的值了，

我们在karaf的deploy或者etc下创建com.lala.service.datasource-xxx.cfg  其中，xxx是任意的字符串（最好不要是特殊字符）

比如说：com.lala.service.datasource-mysql01.cfg

内容如下

id=mysql01
username=
password=
driverClassName=
url=
initialSize=
maxIdle=
maxTotal=
minIdle=

以后，只要扔一个com.lala.service.datasource-xxx.cfg的文件到deploy目录中，就可以创建一个javax.sql.DataSource服务

删除对应的文件，相应的服务，也会被删除

六，服务的使用

（1）编程方式的引用

/** * @param context * @param id 表示配置文件里面的id值  * @throws Exception */private DataSource getDataSource(BundleContext context, String id)throws Exception{String filter = "(DataSourceInstanceId="+id+")";Collection<ServiceReference<DataSource>> colls = context.getServiceReferences(DataSource.class, filter);if(colls != null && !colls.isEmpty()){ServiceReference<DataSource> ref = colls.iterator().next();if(ref != null){return context.getService(ref);}}return null;}

（2）blueprint.xml的引用

<reference interface="javax.sql.DataSource" filter="(DataSourceInstanceId=mysql01)"></reference>