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 static URL valueOf(URL url, String[] reserveParams, String[] reserveParamPrefixs) {
        Map<String, String> newMap = new HashMap<>();
        Map<String, String> oldMap = url.getParameters();
        if (reserveParamPrefixs != null && reserveParamPrefixs.length != 0) {
            for (Map.Entry<String, String> entry : oldMap.entrySet()) {
                for (String reserveParamPrefix : reserveParamPrefixs) {
                    if (entry.getKey().startsWith(reserveParamPrefix) && StringUtils.isNotEmpty(entry.getValue())) {
                        newMap.put(entry.getKey(), entry.getValue());
                    }
                }
            }
        }
        if (reserveParams != null) {
            for (String reserveParam : reserveParams) {
                String tmp = oldMap.get(reserveParam);
                if (StringUtils.isNotEmpty(tmp)) {
                    newMap.put(reserveParam, tmp);
                }
            }
        }
        return newMap.isEmpty() ? new URL(url.getProtocol(), url.getUsername(), url.getPassword(), url.getHost(), url.getPort(), url.getPath())
                : new URL(url.getProtocol(), url.getUsername(), url.getPassword(), url.getHost(), url.getPort(), url.getPath(), newMap);
    }
    public static String encode(String value) {
        if (StringUtils.isEmpty(value)) {
            return "";
        }
        try {
            return URLEncoder.encode(value, "UTF-8");