consumer配置：
    <dubbo:reference id="demoService" check="false" interface="com.alibaba.dubbo.demo.DemoService">
        <dubbo:method name="sayHello" timeout="60000" **cache="threadlocal"**/>
    </dubbo:reference>

在执行的过程中，我们发现其实并不会创建ThreadlocalCache，而是用的LruCache，原因是在
![image](https://user-images.githubusercontent.com/14085645/36060257-e63276f2-0e80-11e8-9da7-36e41c7ef23a.png)
可以看到，当将cache配置在方法上而不是服务上的时候，传入的url只有"method.cache"参数而没有"cache"参数，但是CacheFactory$Adaptive这个类并没有作区分。
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.alibaba.dubbo.config.cache;
import com.alibaba.dubbo.config.ApplicationConfig;
import com.alibaba.dubbo.config.ProtocolConfig;
import com.alibaba.dubbo.config.ReferenceConfig;
import com.alibaba.dubbo.config.RegistryConfig;
import com.alibaba.dubbo.config.ServiceConfig;
import junit.framework.TestCase;
import org.junit.Assert;
import org.junit.Test;
/**
 * CacheTest
 */
public class CacheTest extends TestCase {