修复可以从插件类加载器中加载到宿主类的问题

sermant-io · Nov 2, 2023 · baf706a · baf706a
1 parent a1308ed
commit baf706a
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Showing 2 changed files with 58 additions and 29 deletions.
diff --git a/...core/src/main/java/com/huaweicloud/sermant/core/plugin/classloader/PluginClassLoader.java b/...core/src/main/java/com/huaweicloud/sermant/core/plugin/classloader/PluginClassLoader.java
@@ -22,6 +22,7 @@
 import java.net.URL;
 import java.net.URLClassLoader;
 import java.util.HashMap;
+import java.util.Map;
 
 /**
  * 加载插件主模块的类加载器
@@ -37,6 +38,11 @@ public class PluginClassLoader extends URLClassLoader {
      */
     private final boolean useContextLoader;
 
+    /**
+     * 对ClassLoader内部已加载的Class的管理
+     */
+    private final Map<String, Class<?>> pluginClassMap = new HashMap<>();
+
     /**
      * 构造方法
      *
@@ -48,6 +54,23 @@ public PluginClassLoader(URL[] urls, ClassLoader parent) {
         useContextLoader = ConfigManager.getConfig(AgentConfig.class).isUseContextLoader();
     }
 
+    /**
+     * 加载插件服务包中的类并维护
+     *
+     * @param name 全限定名
+     * @return Class对象
+     */
+    private Class<?> loadPluginClass(String name) {
+        if (!pluginClassMap.containsKey(name)) {
+            try {
+                pluginClassMap.put(name, findClass(name));
+            } catch (ClassNotFoundException ignored) {
+                pluginClassMap.put(name, null);
+            }
+        }
+        return pluginClassMap.get(name);
+    }
+
     /**
      * 向类加载器中添加类的搜索路径
      *
@@ -64,42 +87,48 @@ public Class<?> loadClass(String name) throws ClassNotFoundException {
 
     @Override
     public Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
-        Class<?> clazz = null;
+        synchronized (getClassLoadingLock(name)) {
+            Class<?> clazz = loadPluginClass(name);
 
-        try {
-            clazz = super.loadClass(name, resolve);
-        } catch (ClassNotFoundException ignored) {
-            // ignored
-        }
+            // 自身无法加载类，则通过Sermant搜索路径中加载
+            if (clazz == null) {
+                try {
+                    clazz = super.loadClass(name, resolve);
+                } catch (ClassNotFoundException ignored) {
+                    // 捕获类找不到的异常，下一步会进入localLoader中去加载类
+                    // ignored
+                }
+            }
 
-        // 无法从Sermant搜索路径中找到类，则尝试通过线程绑定的局部类加载器加载
-        if (clazz == null) {
-            ClassLoader loader = localLoader.get(Thread.currentThread().getId());
+            // 无法从Sermant搜索路径中找到类，则尝试通过线程绑定的局部类加载器加载
+            if (clazz == null) {
+                ClassLoader loader = localLoader.get(Thread.currentThread().getId());
 
-            if (loader == null && useContextLoader) {
-                loader = Thread.currentThread().getContextClassLoader();
-            }
+                if (loader == null && useContextLoader) {
+                    loader = Thread.currentThread().getContextClassLoader();
+                }
 
-            // 确保局部类加载器不是当前类加载器，否则会stackoverflow
-            if (loader != null && !this.equals(loader)) {
-                try {
-                    clazz = loader.loadClass(name);
-                } catch (ClassNotFoundException e) {
-                    // 无法找到类，忽略，后续抛出异常
+                // 确保局部类加载器不是当前类加载器，否则会stackoverflow
+                if (loader != null && !this.equals(loader)) {
+                    try {
+                        clazz = loader.loadClass(name);
+                    } catch (ClassNotFoundException e) {
+                        // 无法找到类，忽略，后续抛出异常
+                    }
                 }
             }
-        }
 
-        // 如果无法找到类，则抛出异常
-        if (clazz == null) {
-            throw new ClassNotFoundException("Sermant pluginClassLoader can not load class: " + name);
-        }
+            // 如果无法找到类，则抛出异常
+            if (clazz == null) {
+                throw new ClassNotFoundException("Sermant pluginClassLoader can not load class: " + name);
+            }
 
-        // 如果有需要则解析该类
-        if (resolve) {
-            resolveClass(clazz);
+            // 如果有需要则解析该类
+            if (resolve) {
+                resolveClass(clazz);
+            }
+            return clazz;
         }
-        return clazz;
     }
 
     /**

diff --git a/...ore/src/main/java/com/huaweicloud/sermant/core/plugin/classloader/ServiceClassLoader.java b/...ore/src/main/java/com/huaweicloud/sermant/core/plugin/classloader/ServiceClassLoader.java
@@ -55,7 +55,7 @@ public ServiceClassLoader(URL[] urls, ClassLoader parent) {
      * @param name 全限定名
      * @return Class对象
      */
-    private Class<?> loadPluginClass(String name) {
+    private Class<?> loadServiceClass(String name) {
         if (!serviceClassMap.containsKey(name)) {
             try {
                 serviceClassMap.put(name, findClass(name));
@@ -74,7 +74,7 @@ public Class<?> loadClass(String name) throws ClassNotFoundException {
     @Override
     public Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
         synchronized (getClassLoadingLock(name)) {
-            Class<?> clazz = loadPluginClass(name);
+            Class<?> clazz = loadServiceClass(name);
             if (clazz == null) {
                 clazz = super.loadClass(name, resolve);