之前已经写了一篇关于《几种Java热插拔技术实现总结》，在该文中我总结了好几种Java实现热插拔的技术，其中各有优缺点，在这篇文章我将介绍Java热插拔技术在我司项目中的实践。

前言

在开始之前，先看下插件系统的整体框架

• 插件开发模拟环境
  “插件开发模拟环境”主要用于插件的开发和测试，一个独立项目，提供给插件开发人员使用。开发模拟环境依赖插件核心包、插件依赖的主程序包。
  插件核心包-负责插件的加载，安装、注册、卸载
  插件依赖的主程序包-提供插件开发测试的主程序依赖
• 主程序
  插件的正式安装使用环境，线上环境。插件在本地开发测试完成后，通过插件管理页面安装到线上环境进行插件验证。可以分多个环境，线上dev环境提供插件的线上验证，待验证完成后，再发布到prod环境。

代码实现

插件加载流程

在监听到Spring Boot启动后，插件开始加载，从配置文件中获取插件配置、创建插件监听器（用于主程序监听插件启动、停止事件，根据事件自定逻辑）、根据获取的插件配置从指定目录加载插件配置信息（插件id、插件版本、插件描述、插件所在路径、插件启动状态(后期更新)）、配置信息加载完成后将插件class类注册到Spring返回插件上下文、最后启动完成。

插件核心包

基础常量和类

PluginConstants
插件常量

public class PluginConstants {

    public static final String TARGET = "target";

    public static final String POM = "pom.xml";

    public static final String JAR_SUFFIX = ".jar";
    
    public static final String REPACKAGE = "repackage";

    public static final String CLASSES = "classes";

    public static final String CLASS_SUFFIX = ".class";
    
    public static final String MANIFEST = "MANIFEST.MF";
    
    public static final String PLUGINID = "pluginId";
    
    public static final String PLUGINVERSION = "pluginVersion";
    
    public static final String PLUGINDESCRIPTION = "pluginDescription";
}

PluginState
插件状态

@AllArgsConstructor
public enum PluginState {
	/**
     * 被禁用状态
     */
    DISABLED("DISABLED"),

    /**
     * 启动状态
     */
    STARTED("STARTED"),


    /**
     * 停止状态
     */
    STOPPED("STOPPED");
	
	private final String status;

}

RuntimeMode
插件运行环境

@Getter
@AllArgsConstructor
public enum  RuntimeMode {

    /**
     * 开发环境
     */
    DEV("dev"),

    /**
     * 生产环境
     */
    PROD("prod");

    private final String mode;

    public static RuntimeMode byName(String model){
        if(DEV.name().equalsIgnoreCase(model)){
            return RuntimeMode.DEV;
        } else {
            return RuntimeMode.PROD;
        }
    }
}

PluginInfo
插件基本信息，重写了hashcode和equals，根据插件id进行去重

@Data
@Builder
public class PluginInfo {

	/**
	 * 插件id
	 */
	private String id;
	
	/**
	 * 版本
	 */
	private String version;
	
	/**
	 * 描述
	 */
	private String description;

	/**
	 * 插件路径
	 */
	private String path;
	
	/**
	 * 插件启动状态
	 */
	private PluginState pluginState;

	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		PluginInfo other = (PluginInfo) obj;
		return Objects.equals(id, other.id);
	}

	@Override
	public int hashCode() {
		return Objects.hash(id);
	}

	public void setPluginState(PluginState started) {
		this.pluginState = started;
	}
	
}

插件监听器

PluginListener
插件监听器接口

public interface PluginListener {


    /**
     * 注册插件成功
     * @param pluginInfo 插件信息
     */
    default void startSuccess(PluginInfo pluginInfo){}


    /**
     * 启动失败
     * @param pluginInfo 插件信息
     * @param throwable 异常信息
     */
    default void startFailure(PluginInfo pluginInfo, Throwable throwable){}

    /**
     * 卸载插件成功
     * @param pluginInfo 插件信息
     */
    default void stopSuccess(PluginInfo pluginInfo){}


    /**
     * 停止失败
     * @param pluginInfo 插件信息
     * @param throwable 异常信息
     */
    default void stopFailure(PluginInfo pluginInfo, Throwable throwable){}
}

DefaultPluginListenerFactory
插件监听工厂，对自定义插件监听器发送事件

public class DefaultPluginListenerFactory implements PluginListener {
	private final List<PluginListener> listeners;

    public DefaultPluginListenerFactory(ApplicationContext applicationContext){
        listeners = new ArrayList<>();
        addExtendPluginListener(applicationContext);
    }

    public DefaultPluginListenerFactory(){
        listeners = new ArrayList<>();
    }


    private void addExtendPluginListener(ApplicationContext applicationContext){
    	Map<String, PluginListener> beansOfTypeMap = applicationContext.getBeansOfType(PluginListener.class);
    	if (!beansOfTypeMap.isEmpty()) {
    		listeners.addAll(beansOfTypeMap.values());
		}
    }

    public synchronized void addPluginListener(PluginListener pluginListener) {
        if(pluginListener != null){
            listeners.add(pluginListener);
        }
    }

    public List<PluginListener> getListeners() {
        return listeners;
    }


    @Override
    public void startSuccess(PluginInfo pluginInfo) {
        for (PluginListener listener : listeners) {
            try {
                listener.startSuccess(pluginInfo);
            } catch (Exception e) {
            	
            }
        }
    }

    @Override
    public void startFailure(PluginInfo pluginInfo, Throwable throwable) {
        for (PluginListener listener : listeners) {
            try {
                listener.startFailure(pluginInfo, throwable);
            } catch (Exception e) {
            	
            }
        }
    }

    @Override
    public void stopSuccess(PluginInfo pluginInfo) {
        for (PluginListener listener : listeners) {
            try {
                listener.stopSuccess(pluginInfo);
            } catch (Exception e) {
            		
            }
        }
    }

    @Override
    public void stopFailure(PluginInfo pluginInfo, Throwable throwable) {
        for (PluginListener listener : listeners) {
            try {
                listener.stopFailure(pluginInfo, throwable);
            } catch (Exception e) {
            	
            }
        }
    }
}

工具类

DeployUtils
部署工具类，读取jar包中的文件，判断class是否为Spring bean等

@Slf4j
public class DeployUtils {
	/**
	 * 读取jar包中所有类文件
	 */
	public static Set<String> readJarFile(String jarAddress) {
	    Set<String> classNameSet = new HashSet<>();
	    
	    try(JarFile jarFile = new JarFile(jarAddress)) {
	    	Enumeration<JarEntry> entries = jarFile.entries();//遍历整个jar文件
		    while (entries.hasMoreElements()) {
		        JarEntry jarEntry = entries.nextElement();
		        String name = jarEntry.getName();
		        if (name.endsWith(PluginConstants.CLASS_SUFFIX)) {
		            String className = name.replace(PluginConstants.CLASS_SUFFIX, "").replaceAll("/", ".");
		            classNameSet.add(className);
		        }
		    }
		} catch (Exception e) {
			log.warn("加载jar包失败", e);
		}
	    return classNameSet;
	}

	public static InputStream readManifestJarFile(File jarAddress) {
		try {
			JarFile jarFile = new JarFile(jarAddress);
			//遍历整个jar文件
			Enumeration<JarEntry> entries = jarFile.entries();
			while (entries.hasMoreElements()) {
				JarEntry jarEntry = entries.nextElement();
				String name = jarEntry.getName();
				if (name.contains(PluginConstants.MANIFEST)) {
					return jarFile.getInputStream(jarEntry);
				}
			}
		} catch (Exception e) {
			log.warn("加载jar包失败", e);
		}
		return null;
	}

	/**
	 * 方法描述 判断class对象是否带有spring的注解
	 */
	public static boolean isSpringBeanClass(Class<?> cls) {
	    if (cls == null) {
	        return false;
	    }
	    //是否是接口
	    if (cls.isInterface()) {
	        return false;
	    }
	    //是否是抽象类
	    if (Modifier.isAbstract(cls.getModifiers())) {
	        return false;
	    }
	    if (cls.getAnnotation(Component.class) != null) {
	        return true;
	    }
	    if (cls.getAnnotation(Mapper.class) != null) {
	        return true;
	    }
	    if (cls.getAnnotation(Service.class) != null) {
	        return true;
	    }
		if (cls.getAnnotation(RestController.class) != null) {
			return true;
		}
	    return false;
	}
	
	
	public static boolean isController(Class<?> cls) {
		if (cls.getAnnotation(Controller.class) != null) {
			return true;
		}
		if (cls.getAnnotation(RestController.class) != null) {
			return true;
		}
		return false;
	}

	public static boolean isHaveRequestMapping(Method method) {
		return AnnotationUtils.findAnnotation(method, RequestMapping.class) != null;
	}
	
	/**
	 * 类名首字母小写 作为spring容器beanMap的key
	 */
	public static String transformName(String className) {
	    String tmpstr = className.substring(className.lastIndexOf(".") + 1);
	    return tmpstr.substring(0, 1).toLowerCase() + tmpstr.substring(1);
	}

	/**
	 * 读取class文件
	 * @param path
	 * @return
	 */
	public static Set<String> readClassFile(String path) {
		if (path.endsWith(PluginConstants.JAR_SUFFIX)) {
			return readJarFile(path);
		} else {
			List<File> pomFiles =  FileUtil.loopFiles(path, file -> file.getName().endsWith(PluginConstants.CLASS_SUFFIX));
			Set<String> classNameSet = new HashSet<>();
			for (File file : pomFiles) {
				String className = CharSequenceUtil.subBetween(file.getPath(), PluginConstants.CLASSES + File.separator, PluginConstants.CLASS_SUFFIX).replace(File.separator, ".");
				classNameSet.add(className);
			}
			return classNameSet;
		}
	}
}

插件自动化配置

PluginAutoConfiguration
插件自动化配置信息

@ConfigurationProperties(prefix = "plugin")
@Data
public class PluginAutoConfiguration {

    /**
     * 是否启用插件功能
     */
    @Value("${enable:true}")
    private Boolean enable;
    
    /**
     * 运行模式
     *  开发环境: development、dev
     *  生产/部署 环境: deployment、prod
     */
    @Value("${runMode:dev}")
    private String runMode;
    
    /**
     * 插件的路径
     */
    private List<String> pluginPath;
    
    /**
     * 在卸载插件后, 备份插件的目录
     */
    @Value("${backupPath:backupPlugin}")
    private String backupPath;

    public RuntimeMode environment() {
        return RuntimeMode.byName(runMode);
    }
}

PluginStarter
插件自动化配置，配置在spring.factories中

@Configuration(proxyBeanMethods = true)
@EnableConfigurationProperties(PluginAutoConfiguration.class)
@Import(DefaultPluginApplication.class)
public class PluginStarter {

}

PluginConfiguration
配置插件管理操作类，主程序可以注入该类，操作插件的安装、卸载、获取插件上下文

@Configuration
public class PluginConfiguration {
    @Bean
    public PluginManager createPluginManager(PluginAutoConfiguration configuration, ApplicationContext applicationContext) {
        return new DefaultPluginManager(configuration, applicationContext);
    }
}

插件加载注册

DefaultPluginApplication
监听Spring Boot启动完成，加载插件，调用父类的加载方法，获取主程序上下文

import org.springframework.beans.BeansException;
import org.springframework.boot.context.event.ApplicationStartedEvent;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ApplicationListener;
import org.springframework.context.annotation.Import;

@Import(PluginConfiguration.class)
public class DefaultPluginApplication extends AbstractPluginApplication implements ApplicationContextAware, ApplicationListener<ApplicationStartedEvent> {
	
	private ApplicationContext applicationContext;

	//主程序启动后加载插件
	@Override
	public void onApplicationEvent(ApplicationStartedEvent event) {
		super.initialize(applicationContext);
	}

	@Override
	public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
		this.applicationContext = applicationContext;
	}

}

AbstractPluginApplication
提供插件的加载，从主程序中获取插件配置，获取插件管理操作类

import java.util.Objects;
import java.util.concurrent.atomic.AtomicBoolean;

import org.springframework.beans.factory.BeanCreationException;
import org.springframework.context.ApplicationContext;

import lombok.extern.slf4j.Slf4j;

@Slf4j
public abstract class AbstractPluginApplication {
	
	private final AtomicBoolean beInitialized = new AtomicBoolean(false);

	public synchronized void initialize(ApplicationContext applicationContext) {
		Objects.requireNonNull(applicationContext, "ApplicationContext can't be null");
        if(beInitialized.get()) {
            throw new RuntimeException("Plugin has been initialized");
        }
		//获取配置
        PluginAutoConfiguration configuration = getConfiguration(applicationContext);
        
        if (Boolean.FALSE.equals(configuration.getEnable())) {
        	log.info("插件已禁用");
        	return;
		}
        
        try {
        	log.info("插件加载环境: {},插件目录: {}", configuration.getRunMode(), String.join(",", configuration.getPluginPath()));
    		
        	DefaultPluginManager pluginManager = getPluginManager(applicationContext);
			pluginManager.createPluginListenerFactory();
			pluginManager.loadPlugins();
			beInitialized.set(true);
			
			log.info("插件启动完成");
		} catch (Exception e) {
			log.error("初始化插件异常", e);
		}
	}
	
	protected PluginAutoConfiguration getConfiguration(ApplicationContext applicationContext) {
		PluginAutoConfiguration configuration = null;
        try {
            configuration = applicationContext.getBean(PluginAutoConfiguration.class);
        } catch (Exception e){
            // no show exception
        }
        if(configuration == null){
            throw new BeanCreationException("没有发现 <PluginAutoConfiguration> Bean");
        }
        return configuration;
    }
	
	protected DefaultPluginManager getPluginManager(ApplicationContext applicationContext) {
		DefaultPluginManager pluginManager = null;
        try {
        	pluginManager = applicationContext.getBean(DefaultPluginManager.class);
        } catch (Exception e){
            // no show exception
        }
        if(pluginManager == null){
            throw new BeanCreationException("没有发现 <DefaultPluginManager> Bean");
        }
        return pluginManager;
    }
}

DefaultPluginManager
插件操作类，管理插件的加载、安装、卸载，主程序使用该类对插件进行操作

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.annotation.Annotation;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.jar.Attributes;
import java.util.jar.Manifest;

import org.apache.maven.model.Model;
import org.apache.maven.model.io.xpp3.MavenXpp3Reader;
import org.codehaus.plexus.util.xml.pull.XmlPullParserException;
import org.springframework.context.ApplicationContext;

import com.greentown.plugin.constants.PluginConstants;
import com.greentown.plugin.constants.PluginState;
import com.greentown.plugin.constants.RuntimeMode;
import com.greentown.plugin.listener.DefaultPluginListenerFactory;
import com.greentown.plugin.util.DeployUtils;

import cn.hutool.core.collection.CollUtil;
import cn.hutool.core.date.DateUtil;
import cn.hutool.core.io.FileUtil;
import cn.hutool.core.io.file.PathUtil;
import cn.hutool.core.text.CharSequenceUtil;
import lombok.extern.slf4j.Slf4j;

@Slf4j
public class DefaultPluginManager implements PluginManager {
	
	private PluginAutoConfiguration pluginAutoConfiguration;
	private ApplicationContext applicationContext;
	private DefaultPluginListenerFactory pluginListenerFactory;
	private PluginClassRegister pluginClassRegister;
	private Map<String, ApplicationContext> pluginBeans = new ConcurrentHashMap<>();
	private Map<String, PluginInfo> pluginInfoMap = new ConcurrentHashMap<>();

	private final AtomicBoolean loaded = new AtomicBoolean(false);
	

	public DefaultPluginManager(PluginAutoConfiguration pluginAutoConfiguration,
			ApplicationContext applicationContext) {
		this.pluginAutoConfiguration = pluginAutoConfiguration;
		this.applicationContext = applicationContext;
		this.pluginClassRegister = new PluginClassRegister(applicationContext, pluginAutoConfiguration, pluginBeans);
	}
	
	public void createPluginListenerFactory() {
		this.pluginListenerFactory = new DefaultPluginListenerFactory(applicationContext);
	}

	@Override
	public List<PluginInfo> loadPlugins() throws Exception {
		if(loaded.get()){
			throw new PluginException("不能重复调用: loadPlugins");
		}
		//从配置路径获取插件目录
		//解析插件jar包中的配置，生成配置对象
		List<PluginInfo> pluginInfoList = loadPluginsFromPath(pluginAutoConfiguration.getPluginPath());
		if (CollUtil.isEmpty(pluginInfoList)) {
			log.warn("路径下未发现任何插件");
			return pluginInfoList;
		}
		
		//注册插件
		for (PluginInfo pluginInfo : pluginInfoList) {
			start(pluginInfo);
		}
		loaded.set(true);
		return pluginInfoList;
	}

	private List<PluginInfo> loadPluginsFromPath(List<String> pluginPath) throws IOException, XmlPullParserException {
		List<PluginInfo> pluginInfoList = new ArrayList<>();
		for (String path : pluginPath) {
			Path resolvePath = Paths.get(path);
			Set<PluginInfo> pluginInfos = buildPluginInfo(resolvePath);
			pluginInfoList.addAll(pluginInfos);
		}
	    return pluginInfoList;
	}

	private Set<PluginInfo> buildPluginInfo(Path path) throws IOException, XmlPullParserException {
		Set<PluginInfo> pluginInfoList = new HashSet<>();
		//开发环境
		if (RuntimeMode.DEV == pluginAutoConfiguration.environment()) {
			List<File> pomFiles =  FileUtil.loopFiles(path.toString(), file -> PluginConstants.POM.equals(file.getName()));
			for (File file : pomFiles) {
				MavenXpp3Reader reader = new MavenXpp3Reader();
				Model model = reader.read(new FileInputStream(file));
				PluginInfo pluginInfo = PluginInfo.builder().id(model.getArtifactId())
						.version(model.getVersion() == null ? model.getParent().getVersion() : model.getVersion())
						.description(model.getDescription()).build();
				//开发环境重新定义插件路径，需要指定到classes目录
				pluginInfo.setPath(CharSequenceUtil.subBefore(path.toString(), pluginInfo.getId(), false) 
						+ File.separator + pluginInfo.getId()
						+ File.separator + PluginConstants.TARGET
						+ File.separator + PluginConstants.CLASSES);
				pluginInfoList.add(pluginInfo);
			}
		}

		//生产环境从jar包中读取
		if (RuntimeMode.PROD == pluginAutoConfiguration.environment()) {
			//获取jar包列表
			List<File> jarFiles =  FileUtil.loopFiles(path.toString(), file -> file.getName().endsWith(PluginConstants.REPACKAGE + PluginConstants.JAR_SUFFIX));
			for (File jarFile : jarFiles) {
				//读取配置
				try(InputStream jarFileInputStream = DeployUtils.readManifestJarFile(jarFile)) {
					Manifest manifest = new Manifest(jarFileInputStream);
					Attributes attr = manifest.getMainAttributes();
					PluginInfo pluginInfo = PluginInfo.builder().id(attr.getValue(PluginConstants.PLUGINID))
							.version(attr.getValue(PluginConstants.PLUGINVERSION))
							.description(attr.getValue(PluginConstants.PLUGINDESCRIPTION))
							.path(jarFile.getPath()).build();
					pluginInfoList.add(pluginInfo);
				} catch (Exception e) {
					log.warn("插件{}配置读取异常", jarFile.getName());
				}
			}
		}
		return pluginInfoList;
	}

	@Override
	public PluginInfo install(Path pluginPath) {
		if (RuntimeMode.PROD != pluginAutoConfiguration.environment()) {
			throw new PluginException("插件安装只适用于生产环境");
		}
		try {
			Set<PluginInfo> pluginInfos = buildPluginInfo(pluginPath);
			if (CollUtil.isEmpty(pluginInfos)) {
				throw new PluginException("插件不存在");
			}
			PluginInfo pluginInfo = (PluginInfo) pluginInfos.toArray()[0];
			if (pluginInfoMap.get(pluginInfo.getId()) != null) {
				log.info("已存在同类插件{}，将覆盖安装", pluginInfo.getId());
			}
			uninstall(pluginInfo.getId());
			start(pluginInfo);
			return pluginInfo;
		} catch (Exception e) {
			throw new PluginException("插件安装失败", e); 
		}
	}

	private void start(PluginInfo pluginInfo) {
		try {
			pluginClassRegister.register(pluginInfo);
			pluginInfo.setPluginState(PluginState.STARTED);
			pluginInfoMap.put(pluginInfo.getId(), pluginInfo);
			log.info("插件{}启动成功", pluginInfo.getId());
			pluginListenerFactory.startSuccess(pluginInfo);
		} catch (Exception e) {
			log.error("插件{}注册异常", pluginInfo.getId(), e);
			pluginListenerFactory.startFailure(pluginInfo, e);
		}
	}

	@Override
	public void uninstall(String pluginId) {
		if (RuntimeMode.PROD != pluginAutoConfiguration.environment()) {
			throw new PluginException("插件卸载只适用于生产环境");
		}
		PluginInfo pluginInfo = pluginInfoMap.get(pluginId);
		if (pluginInfo == null) {
			return;
		}
		stop(pluginInfo);
		backupPlugin(pluginInfo);
		clear(pluginInfo);
	}
	
	@Override
	public PluginInfo start(String pluginId) {
		PluginInfo pluginInfo = pluginInfoMap.get(pluginId);
		start(pluginInfo);
		return pluginInfo;
	}

	@Override
	public PluginInfo stop(String pluginId) {
		PluginInfo pluginInfo = pluginInfoMap.get(pluginId);
		stop(pluginInfo);
		return pluginInfo;
	}

	private void clear(PluginInfo pluginInfo) {
		PathUtil.del(Paths.get(pluginInfo.getPath()));
		pluginInfoMap.remove(pluginInfo.getId());
	}

	private void stop(PluginInfo pluginInfo) {
		try {
			pluginClassRegister.unRegister(pluginInfo);
			pluginInfo.setPluginState(PluginState.STOPPED);
			pluginListenerFactory.stopSuccess(pluginInfo);
			log.info("插件{}停止成功", pluginInfo.getId());
		} catch (Exception e) {
			log.error("插件{}停止异常", pluginInfo.getId(), e);
		}
	}

	private void backupPlugin(PluginInfo pluginInfo) {
		String backupPath = pluginAutoConfiguration.getBackupPath();
		if (CharSequenceUtil.isBlank(backupPath)) {
			return;
		}
		String newName = pluginInfo.getId() + DateUtil.now() + PluginConstants.JAR_SUFFIX;
		String newPath = backupPath + File.separator + newName;
		FileUtil.copyFile(pluginInfo.getPath(), newPath);
	}

	@Override
	public ApplicationContext getApplicationContext(String pluginId) {
		return pluginBeans.get(pluginId);
	}

	@Override
	public List<Object> getBeansWithAnnotation(String pluginId, Class<? extends Annotation> annotationType) {
		ApplicationContext pluginApplicationContext = pluginBeans.get(pluginId);
		if(pluginApplicationContext != null){
			Map<String, Object> beanMap = pluginApplicationContext.getBeansWithAnnotation(annotationType);
			return new ArrayList<>(beanMap.values());
		}
		return new ArrayList<>(0);
	}
}

PluginClassRegister
插件动态注册、动态卸载，解析插件class，判断是否为Spring Bean或Spring 接口，是注册到Spring 中

public class PluginClassRegister {

	private ApplicationContext applicationContext;
	private RequestMappingHandlerMapping requestMappingHandlerMapping;
	private Method getMappingForMethod;
	private PluginAutoConfiguration configuration;
	private Map<String, ApplicationContext> pluginBeans;

	private Map<String, Set<RequestMappingInfo>> requestMappings = new ConcurrentHashMap<>();


	public PluginClassRegister(ApplicationContext applicationContext, PluginAutoConfiguration configuration, Map<String, ApplicationContext> pluginBeans) {
		this.applicationContext = applicationContext;
		this.requestMappingHandlerMapping = getRequestMapping();
		this.getMappingForMethod = getRequestMethod();
		this.configuration = configuration;
		this.pluginBeans = pluginBeans;
	}


	public ApplicationContext register(PluginInfo pluginInfo) {
		ApplicationContext pluginApplicationContext =  registerBean(pluginInfo);
		pluginBeans.put(pluginInfo.getId(), pluginApplicationContext);
		return pluginApplicationContext;
	}
	
	public boolean unRegister(PluginInfo pluginInfo) {
		return unRegisterBean(pluginInfo);
	}

	private boolean unRegisterBean(PluginInfo pluginInfo) {
		GenericWebApplicationContext pluginApplicationContext = (GenericWebApplicationContext) pluginBeans.get(pluginInfo.getId());
		pluginApplicationContext.close();
		//取消注册controller
		Set<RequestMappingInfo> requestMappingInfoSet = requestMappings.get(pluginInfo.getId());
		if (requestMappingInfoSet != null) {
			requestMappingInfoSet.forEach(this::unRegisterController);
		}
		requestMappings.remove(pluginInfo.getId());
		pluginBeans.remove(pluginInfo.getId());
		return true;
	}

	private void unRegisterController(RequestMappingInfo requestMappingInfo) {
		requestMappingHandlerMapping.unregisterMapping(requestMappingInfo);
	}

	private ApplicationContext registerBean(PluginInfo pluginInfo) {
		String path = pluginInfo.getPath();
		Set<String> classNames = DeployUtils.readClassFile(path);
		URLClassLoader classLoader = null;
		try {
			//class 加载器
			URL jarURL = new File(path).toURI().toURL();
			classLoader = new URLClassLoader(new URL[] { jarURL }, Thread.currentThread().getContextClassLoader());

			//一个插件创建一个applicationContext
			GenericWebApplicationContext pluginApplicationContext = new GenericWebApplicationContext();
			pluginApplicationContext.setResourceLoader(new DefaultResourceLoader(classLoader));

			//注册bean
			List<String> beanNames = new ArrayList<>();
			for (String className : classNames) {
				Class clazz = classLoader.loadClass(className);
				if (DeployUtils.isSpringBeanClass(clazz)) {
					String simpleClassName = DeployUtils.transformName(className);

					BeanDefinitionRegistry beanDefinitonRegistry = (BeanDefinitionRegistry) pluginApplicationContext.getBeanFactory();
					BeanDefinitionBuilder usersBeanDefinitionBuilder = BeanDefinitionBuilder.genericBeanDefinition(clazz);
					usersBeanDefinitionBuilder.setScope("singleton");
					beanDefinitonRegistry.registerBeanDefinition(simpleClassName, usersBeanDefinitionBuilder.getRawBeanDefinition());

					beanNames.add(simpleClassName);
				}
			}
			//刷新上下文
			pluginApplicationContext.refresh();
			//注入bean和注册接口
			Set<RequestMappingInfo> pluginRequestMappings = new HashSet<>();
			for (String beanName : beanNames) {
				//注入bean
				Object bean = pluginApplicationContext.getBean(beanName);
				injectService(bean);
				//注册接口
				Set<RequestMappingInfo> requestMappingInfos = registerController(bean);
				requestMappingInfos.forEach(requestMappingInfo -> {
					log.info("插件{}注册接口{}", pluginInfo.getId(), requestMappingInfo);
				});
				pluginRequestMappings.addAll(requestMappingInfos);
			}
			requestMappings.put(pluginInfo.getId(), pluginRequestMappings);

			return pluginApplicationContext;
		} catch (Exception e) {
			throw new PluginException("注册bean异常", e);
		} finally {
			try {
				if (classLoader != null) {
					classLoader.close();
				}
			} catch (IOException e) {
				log.error("classLoader关闭失败", e);
			}
		}
	}

	private Set<RequestMappingInfo> registerController(Object bean) {
		Class<?> aClass = bean.getClass();
		Set<RequestMappingInfo> requestMappingInfos = new HashSet<>();
		if (Boolean.TRUE.equals(DeployUtils.isController(aClass))) {
			Method[] methods = aClass.getDeclaredMethods();
			for (Method method : methods) {
				if (DeployUtils.isHaveRequestMapping(method)) {
					try {
						RequestMappingInfo requestMappingInfo = (RequestMappingInfo)
								getMappingForMethod.invoke(requestMappingHandlerMapping, method, aClass);
						requestMappingHandlerMapping.registerMapping(requestMappingInfo, bean, method);
						requestMappingInfos.add(requestMappingInfo);
					} catch (Exception e){
						log.error("接口注册异常", e);
					}
				}
			}
		}
		return requestMappingInfos;
	}


	private void injectService(Object instance){
		if (instance==null) {
			return;
		}

		Field[] fields = ReflectUtil.getFields(instance.getClass()); //instance.getClass().getDeclaredFields();
		for (Field field : fields) {
			if (Modifier.isStatic(field.getModifiers())) {
				continue;
			}

			Object fieldBean = null;
			// with bean-id, bean could be found by both @Resource and @Autowired, or bean could only be found by @Autowired

			if (AnnotationUtils.getAnnotation(field, Resource.class) != null) {
				try {
					Resource resource = AnnotationUtils.getAnnotation(field, Resource.class);
					if (resource.name()!=null && resource.name().length()>0){
						fieldBean = applicationContext.getBean(resource.name());
					} else {
						fieldBean = applicationContext.getBean(field.getName());
					}
				} catch (Exception e) {
				}
				if (fieldBean==null ) {
					fieldBean = applicationContext.getBean(field.getType());
				}
			} else if (AnnotationUtils.getAnnotation(field, Autowired.class) != null) {
				Qualifier qualifier = AnnotationUtils.getAnnotation(field, Qualifier.class);
				if (qualifier!=null && qualifier.value()!=null && qualifier.value().length()>0) {
					fieldBean = applicationContext.getBean(qualifier.value());
				} else {
					fieldBean = applicationContext.getBean(field.getType());
				}
			}

			if (fieldBean!=null) {
				field.setAccessible(true);
				try {
					field.set(instance, fieldBean);
				} catch (IllegalArgumentException e) {
					log.error(e.getMessage(), e);
				} catch (IllegalAccessException e) {
					log.error(e.getMessage(), e);
				}
			}
		}
	}

	private Method getRequestMethod() {
		try {
			Method method =  ReflectUtils.findDeclaredMethod(requestMappingHandlerMapping.getClass(), "getMappingForMethod", new Class[] { Method.class, Class.class });
			method.setAccessible(true);
			return method;
		} catch (Exception ex) {
			log.error("反射获取detectHandlerMethods异常", ex);
		}
		return null;
	}

	private RequestMappingHandlerMapping getRequestMapping() {
		return (RequestMappingHandlerMapping) applicationContext.getBean("requestMappingHandlerMapping");
	}

}

插件Mock包

plugin-mock
提供插件的开发模拟测试相关的依赖，以Jar包方式提供，根据具体项目提供依赖

插件开发环境

一个独立的项目，依赖上述提供的插件核心包、插件Mock包，提供给插件开发人员使用。
main-application：插件开发测试的主程序
plugins：插件开发目录

总结

在最开始的使用，我们的插件使用Spring Brick来开发，光在集成过程中就发现不少问题，特别是依赖冲突很多，并且对插件的加载比较慢，导致主程序启动慢。
在自研插件后，该插件加载启动使用动态注入Spring的方式，相比较Spring Brick的插件独立Spring Boot方式加载速度更快，占用内存更小，虽然还不支持Freemark、AOP等框架，但对于此类功能后期也可以通过后置处理器扩展。