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。
this.host = null;
        this.port = 0;
        this.path = null;
        this.parameters = null;
    }
    public URL(String protocol, String host, int port) {
        this(protocol, null, null, host, port, null, (Map<String, String>) null);
    }
    public URL(String protocol, String host, int port, String[] pairs) { 
        this(protocol, null, null, host, port, null, CollectionUtils.toStringMap(pairs));
    }
    public URL(String protocol, String host, int port, Map<String, String> parameters) {
        this(protocol, null, null, host, port, null, parameters);
    }
    public URL(String protocol, String host, int port, String path) {
        this(protocol, null, null, host, port, path, (Map<String, String>) null);
    }
    public URL(String protocol, String host, int port, String path, String... pairs) {
        this(protocol, null, null, host, port, path, CollectionUtils.toStringMap(pairs));
    }
    public URL(String protocol, String host, int port, String path, Map<String, String> parameters) {
        this(protocol, null, null, host, port, path, parameters);
    }
    public URL(String protocol, String username, String password, String host, int port, String path) {
        this(protocol, username, password, host, port, path, (Map<String, String>) null);
    }
    public URL(String protocol, String username, String password, String host, int port, String path, String... pairs) {
        this(protocol, username, password, host, port, path, CollectionUtils.toStringMap(pairs));
    }
    public URL(String protocol, String username, String password, String host, int port, String path, Map<String, String> parameters) {