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 static org.hamcrest.MatcherAssert.assertThat;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNull;
import static org.junit.jupiter.api.Assertions.assertSame;
import static org.junit.jupiter.api.Assertions.assertTrue;
import static org.junit.jupiter.api.Assertions.fail;
public class URLTest {
    @Test
    public void test_valueOf_noProtocolAndHost() throws Exception {
        URL url = URL.valueOf("/context/path?version=1.0.0&application=morgan");
        assertNull(url.getProtocol());
        assertNull(url.getUsername());
        assertNull(url.getPassword());
        assertNull(url.getHost());
        assertEquals(0, url.getPort());
        assertEquals("context/path", url.getPath());
        assertEquals(2, url.getParameters().size());
        assertEquals("1.0.0", url.getParameter("version"));
        assertEquals("morgan", url.getParameter("application"));
        url = URL.valueOf("context/path?version=1.0.0&application=morgan");
        
        assertNull(url.getProtocol());
        assertNull(url.getUsername());
        assertNull(url.getPassword());
        assertEquals("context", url.getHost());
        assertEquals(0, url.getPort());
        assertEquals("path", url.getPath());
        assertEquals(2, url.getParameters().size());
        assertEquals("1.0.0", url.getParameter("version"));
        assertEquals("morgan", url.getParameter("application"));