Classnotfoundexception exception is reported when reflection is used in bundle.

Tag: osgi bundle reflection

Source code download

User-model:

User-model/User:

/**  * @author wumingkun * @version 1.0.0 * @Description */package com.demo.user.user_model;/** * @author wumingkun * */public class User {private int id;private String name;public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String toString() {return "User [id=" + id + ", name=" + name + "]";}}

User-modle/POM. xml

<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.demo.user</groupId><artifactId>user-model</artifactId><version>0.0.1-SNAPSHOT</version><packaging>bundle</packaging><name>user-model</name><url>http://maven.apache.org</url><properties><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding></properties><dependencies><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.10</version><scope>test</scope></dependency></dependencies><build><plugins><plugin><groupId>org.apache.felix</groupId><artifactId>maven-bundle-plugin</artifactId><extensions>true</extensions><configuration><instructions></instructions></configuration></plugin></plugins></build></project>

User-service:

Userservice

/** *  * @author wumingkun * @version 1.0.0 * @Description */package com.demo.user.user_service;/** * @author wumingkun * */public class UserSerivce {public void add(Object obj){System.out.println(obj+" add....");}}

Pom. xml

<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.demo.user</groupId>  <artifactId>user-service</artifactId>  <version>0.0.1-SNAPSHOT</version>  <packaging>bundle</packaging>  <name>user-service</name>  <url>http://maven.apache.org</url>  <properties>    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>  </properties>  <dependencies>    <dependency>      <groupId>junit</groupId>      <artifactId>junit</artifactId>      <version>4.10</version>      <scope>test</scope>    </dependency>  </dependencies>  <build><plugins><plugin><groupId>org.apache.felix</groupId><artifactId>maven-bundle-plugin</artifactId><extensions>true</extensions><configuration><instructions></instructions></configuration></plugin></plugins></build></project>

User-Action:

Activator

/*** @ Author wumingkun * @ version 1.0.0 * @ Description */package COM. demo. user. user_action; import Java. lang. reflect. method; import Org. osgi. framework. bundleactivator; import Org. osgi. framework. bundlecontext; import COM. demo. user. user_service.userserivce;/*** @ author wumingkun ***/public class activator implements bundleactivator {/* (non-javadoc) * @ see Org. osgi. framework. bundleactivator # Start (Org. osgi. framework. bundlecontext) */Public void start (bundlecontext context) throws exception {try {class clz = Class. forname ("com. demo. user. user_model.user "); object OBJ = clz. newinstance (); Method setidmethod = clz. getmethod ("setid", new class [] {Int. class}); setidmethod. invoke (OBJ, 1); Method setnamemethod = clz. getmethod ("setname", new class [] {string. class}); setnamemethod. invoke (OBJ, "Zhang San"); userserivce Serivce = new userserivce (); Serivce. add (OBJ);} catch (exception e) {e. printstacktrace () ;}}/* (non-javadoc) * @ see Org. osgi. framework. bundleactivator # Stop (Org. osgi. framework. bundlecontext) */Public void stop (bundlecontext context) throws exception {}}

</pre>pom.xml<pre name="code" class="html"><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.demo.user</groupId><artifactId>user-action</artifactId><version>0.0.1-SNAPSHOT</version><packaging>bundle</packaging><name>user-action</name><url>http://maven.apache.org</url><properties><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding></properties><dependencies><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.10</version><scope>test</scope></dependency><dependency><groupId>org.osgi</groupId><artifactId>org.osgi.core</artifactId><version>4.2.0</version></dependency><dependency><groupId>com.demo.user</groupId><artifactId>user-service</artifactId><version>0.0.1-SNAPSHOT</version></dependency></dependencies><build><plugins><plugin><groupId>org.apache.felix</groupId><artifactId>maven-bundle-plugin</artifactId><extensions>true</extensions><configuration><instructions><Bundle-Activator>com.demo.user.user_action.Activator</Bundle-Activator></instructions></configuration></plugin></plugins></build></project>

Analysis:

From user-action/POM. XML, we can see that it only depends on user-service. In the activator. Java file, the import part is as follows:

import java.lang.reflect.Method;import org.osgi.framework.BundleActivator;import org.osgi.framework.BundleContext;import com.demo.user.user_service.UserSerivce;

Com. Demo. User. user_model not imported,

View manifest. MF

Manifest-Version: 1.0Bnd-LastModified: 1405153337259Build-Jdk: 1.5.0_22Built-By: AdministratorBundle-Activator: com.demo.user.user_action.ActivatorBundle-ManifestVersion: 2Bundle-Name: user-actionBundle-SymbolicName: com.demo.user.actionBundle-Version: 0.0.1.SNAPSHOTCreated-By: Apache Maven Bundle PluginExport-Package: com.demo.user.user_action;version="0.0.1.SNAPSHOT";uses: ="org.osgi.framework"Import-Package: com.demo.user.user_service;version="[0.0,1)",org.osgi.fr amework;version="[1.5,2)"Tool: Bnd-2.1.0.20130426-122213

It only imports com. Demo. User. user_service and org. osgi. Framework

When running bundle, an error is reported:

java.lang.ClassNotFoundException: com.demo.user.user_model.User

Solution

In Maven-bundle-plugin user-action/POM. XML, add all external packages used by bundle.

<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.demo.user</groupId><artifactId>user-action</artifactId><version>0.0.1-SNAPSHOT</version><packaging>bundle</packaging><name>user-action</name><url>http://maven.apache.org</url><properties><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding></properties><dependencies><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.10</version><scope>test</scope></dependency><dependency><groupId>org.osgi</groupId><artifactId>org.osgi.core</artifactId><version>4.2.0</version></dependency><dependency><groupId>com.demo.user</groupId><artifactId>user-service</artifactId><version>0.0.1-SNAPSHOT</version></dependency></dependencies><build><plugins><plugin><groupId>org.apache.felix</groupId><artifactId>maven-bundle-plugin</artifactId><extensions>true</extensions><configuration><instructions><Bundle-Activator>com.demo.user.user_action.Activator</Bundle-Activator><Import-Package> com.demo.user.user_service,org.osgi.framework,com.demo.user.user_model</Import-Package></instructions></configuration></plugin></plugins></build></project>

View manifest again

Manifest-Version: 1.0Bnd-LastModified: 1405154955217Build-Jdk: 1.5.0_22Built-By: AdministratorBundle-Activator: com.demo.user.user_action.ActivatorBundle-ManifestVersion: 2Bundle-Name: user-actionBundle-SymbolicName: com.demo.user.actionBundle-Version: 0.0.1.SNAPSHOTCreated-By: Apache Maven Bundle PluginExport-Package: com.demo.user.user_action;version="0.0.1.SNAPSHOT";uses: ="org.osgi.framework"Import-Package: com.demo.user.user_service;version="[0.0,1)",org.osgi.fr amework;version="[1.5,2)",com.demo.user.user_modelTool: Bnd-2.1.0.20130426-122213

Deployment and running:

User [ID = 1, name = Michael] add ....