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.common.utils.ConfigUtils;
import org.apache.dubbo.common.utils.NamedThreadFactory;
import org.apache.dubbo.common.utils.StringUtils;
import org.apache.dubbo.config.annotation.Service;
import org.apache.dubbo.config.context.ConfigManager;
import org.apache.dubbo.config.invoker.DelegateProviderMetaDataInvoker;
import org.apache.dubbo.config.support.Parameter;
import org.apache.dubbo.metadata.integration.MetadataReportService;
import org.apache.dubbo.rpc.Exporter;
import org.apache.dubbo.rpc.Invoker;
import org.apache.dubbo.rpc.Protocol;
import org.apache.dubbo.rpc.ProxyFactory;
import org.apache.dubbo.rpc.cluster.ConfiguratorFactory;
import org.apache.dubbo.rpc.model.ApplicationModel;
import org.apache.dubbo.rpc.model.ProviderModel;
import org.apache.dubbo.rpc.service.GenericService;
import org.apache.dubbo.rpc.support.ProtocolUtils;
import java.lang.reflect.Method;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.SocketAddress;
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.UUID;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;