[apache/dubbo]Stub Proxy 配置 Bug

当定义BarService并定义BarServiceStub时，配置如下其实是不会生效的

<dubbo:service interface="com.foo.BarService" stub="true" />

com.alibaba.dubbo.config.ServiceConfig#doExport()

if(local !=null){   // 文档中并没有与local相关的参数解释
    if(local=="true"){
        local=interfaceName+"Local";
    }
    Class<?> localClass;
    try {
        localClass = ClassHelper.forNameWithThreadContextClassLoader(local);
    } catch (ClassNotFoundException e) {
        throw new IllegalStateException(e.getMessage(), e);
    }
    if(!interfaceClass.isAssignableFrom(localClass)){
        throw new IllegalStateException("The local implemention class " + localClass.getName() + " not implement interface " + interfaceName);
    }
}

if(stub !=null){
    if(stub=="true"){ // 最坑爹的错误是这里，文档说stub="true"默认interfaceName+Local（实际是+Stub，参见下一个注释），可是这是String对象啊，如果外面stub赋值不是stub="true"的话，设置了true也不会进来，应该修改为stub.equals("true")，上面Local也一样
        stub=interfaceName+"Stub";  // 这里文档中的解释有误，文档中写的是+Local，即与上面的Local一致
    }
    Class<?> stubClass;
    try {
        stubClass = ClassHelper.forNameWithThreadContextClassLoader(stub);
    } catch (ClassNotFoundException e) {
        throw new IllegalStateException(e.getMessage(), e);
    }
    if(!interfaceClass.isAssignableFrom(stubClass)){
        throw new IllegalStateException("The stub implemention class " + stubClass.getName() + " not implement interface " + interfaceName);
    }
}