getRequestProperty（“ Authorization”）始终返回null

Question

我正在尝试读取HTTP请求的授权标头（因为我需要向其添加一些内容），但是标头值始终为null。其他标头工作正常。

public void testAuth() throws MalformedURLException, IOException{
    URLConnection request = new URL("http://google.com").openConnection();
    request.setRequestProperty("Authorization", "MyHeader");
    request.setRequestProperty("Stackoverflow", "anotherHeader");
    // works fine
    assertEquals("anotherHeader", request.getRequestProperty("Stackoverflow"));
    // Auth header returns null
    assertEquals("MyHeader", request.getRequestProperty("Authorization"));
}

难道我做错了什么？这是“安全”功能吗？有没有办法使它与URLConnection一起使用，还是需要使用另一个HTTP客户端库？

Answer 1

显然，这是安全的“功能”。URLConnection实际上是sun.net.www.protocol.http.HttpURLConnection的实例。它定义getRequestProperty为：

    public String getRequestProperty (String key) {
        // don't return headers containing security sensitive information
        if (key != null) {
            for (int i=0; i < EXCLUDE_HEADERS.length; i++) {
                if (key.equalsIgnoreCase(EXCLUDE_HEADERS[i])) {
                    return null;
                }
            }
        }
        return requests.findValue(key);
    }

该EXCLUDE_HEADERS数组定义为：

   // the following http request headers should NOT have their values
   // returned for security reasons.
   private static final String[] EXCLUDE_HEADERS = {
           "Proxy-Authorization",
           "Authorization"
   };