序
本文主要研究一下dubbo的ClassLoaderFilter
ClassLoaderFilter
dubbo-2.7.2/dubbo-rpc/dubbo-rpc-api/src/main/java/org/apache/dubbo/rpc/filter/ClassLoaderFilter.java
@Activate(group = CommonConstants.PROVIDER, order = -30000)
public class ClassLoaderFilter implements Filter {
@Override
public Result invoke(Invoker> invoker, Invocation invocation) throws RpcException {
ClassLoader ocl = Thread.currentThread().getContextClassLoader();
Thread.currentThread().setContextClassLoader(invoker.getInterface().getClassLoader());
try {
return invoker.invoke(invocation);
} finally {
Thread.currentThread().setContextClassLoader(ocl);
}
}
}
ClassLoaderFilter实现了Filter界面，其invoke方法首先获取当前执行绪的contextClassLoader，然后将其ContextClassLoader设定为invoker.getInterface().getClassLoader()，之后执行invoker.invoke方法，最后将当前执行绪的classLoader重置为原来的contextClassLoader例项
dubbo-2.7.2/dubbo-rpc/dubbo-rpc-api/src/test/java/org/apache/dubbo/rpc/filter/ClassLoaderFilterTest.java
public class ClassLoaderFilterTest {
private ClassLoaderFilter classLoaderFilter = new ClassLoaderFilter();
@Test
public void testInvoke() throws Exception {
URL url = URL.valueOf(test://test:11/test?accesslog=true&group=dubbo&version=1.1);
String path = DemoService.class.getResource(/).getPath();
final URLClassLoader cl = new URLClassLoader(new java.net.URL[]{new java.net.URL(file: + path)}) {
@Override
public Class> loadClass(String name) throws ClassNotFoundException {
try {
return findClass(name);
} catch (ClassNotFoundException e) {
return super.loadClass(name);
}
}
};
final Class> clazz = cl.loadClass(DemoService.class.getCanonicalName());
Invoker invoker = new MyInvoker(url) {
@Override
public Class getInterface() {
return clazz;
}
@Override
public Result invoke(Invocation invocation) throws RpcException {
Assertions.assertEquals(cl, Thread.currentThread().getContextClassLoader());
return null;
}
};
Invocation invocation = Mockito.mock(Invocation.class);
classLoaderFilter.invoke(invoker, invocation);
}
}
这里invoker的interface设定为DemoService.class，然后验证invoke方法里头的Thread.currentThread().getContextClassLoader()为载入DemoService.class的URLClassLoader小结
ClassLoaderFilter实现了Filter界面，其invoke方法首先获取当前执行绪的contextClassLoader，然后将其ContextClassLoader设定为invoker.getInterface().getClassLoader()，之后执行invoker.invoke方法，最后将当前执行绪的classLoader重置为原来的contextClassLoader
doc
ClassLoaderFilter
