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。
@Test
    public void test_addParameter() throws Exception {
        URL url = URL.valueOf("dubbo://admin:hello1234@10.20.130.230:20880/context/path?application=morgan");
        url = url.addParameter("k1", "v1");
        assertEquals("dubbo", url.getProtocol());
        assertEquals("admin", url.getUsername());
        assertEquals("hello1234", url.getPassword());
        assertEquals("10.20.130.230", url.getHost());
        assertEquals(20880, url.getPort());
        assertEquals("context/path", url.getPath());
        assertEquals(2, url.getParameters().size());
        assertEquals("morgan", url.getParameter("application"));
        assertEquals("v1", url.getParameter("k1"));
    }
    @Test
    public void test_addParameter_sameKv() throws Exception {
        URL url = URL.valueOf("dubbo://admin:hello1234@10.20.130.230:20880/context/path?application=morgan&k1=v1");
        URL newUrl = url.addParameter("k1", "v1");
        assertSame(newUrl, url);
    }
    @Test
    public void test_addParameters() throws Exception {
        URL url = URL.valueOf("dubbo://admin:hello1234@10.20.130.230:20880/context/path?application=morgan");
        url = url.addParameters(CollectionUtils.toStringMap("k1", "v1", "k2", "v2"));
        assertEquals("dubbo", url.getProtocol());
        assertEquals("admin", url.getUsername());
        assertEquals("hello1234", url.getPassword());
        assertEquals("10.20.130.230", url.getHost());
        assertEquals(20880, url.getPort());
        assertEquals("context/path", url.getPath());