2.7.0版本getContextPath方法：
```
protected String getContextPath(URL url) {
        String contextPath = url.getPath();
        return contextPath.endsWith("/") ? contextPath.substring(0,contextPath.length()-1) : contextPath;
    }
```
无法将方法置入web容器中，退回2.6.5版本的方法：
```
protected String getContextPath(URL url) {
        int pos = url.getPath().lastIndexOf("/");
        return pos > 0 ? url.getPath().substring(0, pos) : "";
    }
```
使用正常，两个方法应该不等价的。
import org.apache.dubbo.metadata.integration.MetadataReportService;
import org.apache.dubbo.rpc.Invoker;
import org.apache.dubbo.rpc.Protocol;
import org.apache.dubbo.rpc.ProxyFactory;
import org.apache.dubbo.rpc.cluster.Cluster;
import org.apache.dubbo.rpc.cluster.directory.StaticDirectory;
import org.apache.dubbo.rpc.cluster.support.ClusterUtils;
import org.apache.dubbo.rpc.cluster.support.RegistryAwareCluster;
import org.apache.dubbo.rpc.model.ApplicationModel;
import org.apache.dubbo.rpc.model.ConsumerModel;
import org.apache.dubbo.rpc.protocol.injvm.InjvmProtocol;
import org.apache.dubbo.rpc.service.GenericService;
import org.apache.dubbo.rpc.support.ProtocolUtils;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Properties;
/**
 * ReferenceConfig
 *
 * @export
 */
public class ReferenceConfig<T> extends AbstractReferenceConfig {