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。
}
    public URL removeParameter(String key) {
        if (StringUtils.isEmpty(key)) {
            return this;
        }
        return removeParameters(key);
    }
    public URL removeParameters(Collection<String> keys) {
        if (CollectionUtils.isEmpty(keys)) {
            return this;
        }
        return removeParameters(keys.toArray(new String[0]));
    }
    public URL removeParameters(String... keys) {
        if (keys == null || keys.length == 0) {
            return this;
        }
        Map<String, String> map = new HashMap<>(getParameters());
        for (String key : keys) {
            map.remove(key);
        }
        if (map.size() == getParameters().size()) {
            return this;
        }
        return new URL(protocol, username, password, host, port, path, map);
    }
    public URL clearParameters() {
        return new URL(protocol, username, password, host, port, path, new HashMap<>());
    }
    public String getRawParameter(String key) {