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。
return new URL(protocol, username, password, host, port, path, getParameters());
    }
    public String getAuthority() {
        if (StringUtils.isEmpty(username)
                && StringUtils.isEmpty(password)) {
            return null;
        }
        return (username == null ? "" : username)
                + ":" + (password == null ? "" : password);
    }
    public String getHost() {
        return host;
    }
    public URL setHost(String host) {
        return new URL(protocol, username, password, host, port, path, getParameters());
    }
    /**
     * Fetch IP address for this URL.
     * <p>
     * Pls. note that IP should be used instead of Host when to compare with socket's address or to search in a map
     * which use address as its key.
     *
     * @return ip in string format
     */
    public String getIp() {
        if (ip == null) {
            ip = NetUtils.getIpByHost(host);
        }
        return ip;
    }