如何在HttpClient（java、apache）中自动重定向

Question

我创建httpClient并设置设置

HttpClient client = new HttpClient();

client.getParams().setCookiePolicy(CookiePolicy.BROWSER_COMPATIBILITY);
client.getParams().setContentCharset("UTF-8");

第一个请求（get）

GetMethod first = new GetMethod("http://vk.com");
int returnCode = client.executeMethod(first);

BufferedReader br = null;
String lineResult = "";
if (returnCode == HttpStatus.SC_NOT_IMPLEMENTED) {
    System.err.println("The Post method is not implemented by this URI");
    // still consume the response body
    first.getResponseBodyAsString();
} else {
    br = new BufferedReader(new InputStreamReader(first.getResponseBodyAsStream(), Charset.forName("windows-1251")));
    String readLine = "";
    while (((readLine = br.readLine()) != null)) {
        lineResult += readLine;
    }
}

回答正确

第二项要求（职位）：

PostMethod second = new PostMethod("http://login.vk.com/?act=login");

second.setRequestHeader("Referer", "http://vk.com/");

second.addParameter("act", "login");
second.addParameter("al_frame", "1");
second.addParameter("captcha_key", "");
second.addParameter("captcha_sid", "");
second.addParameter("expire", "");
second.addParameter("q", "1");
second.addParameter("from_host", "vk.com");
second.addParameter("email", email);
second.addParameter("pass", password);

returnCode = client.executeMethod(second);

br = null;
lineResult = "";
if (returnCode == HttpStatus.SC_NOT_IMPLEMENTED) {
    System.err.println("The Post method is not implemented by this URI");
    // still consume the response body
    second.getResponseBodyAsString();
} else {
    br = new BufferedReader(new InputStreamReader(second.getResponseBodyAsStream()));
    String readLine = "";
    while (((readLine = br.readLine()) != null)) {
        lineResult += readLine;
    }
}

这个回答也是正确的，但我需要被重定向到标题。地点

我不知道如何从标题位置获取值，或者如何自动启用重定向

Answer 1

您只需添加以下内容：

second.setFollowRedirects(true);

Answer 2

以3为例。在HttpClient的x版本中，您还可以检查响应代码是301还是302，然后使用位置标题重新发布：

client.executeMethod(post);
int status = post.getStatusCode();
if (status == 301 || status == 302) {
  String location = post.getResponseHeader("Location").toString();
  URI uri = new URI(location, false);
  post.setURI(uri);
  client.executeMethod(post);
}

Answer 3

由于设计限制，HttpClient 3。x无法自动处理包含POST和PUT等请求的实体重定向。您必须手动将POST请求转换为GET-On重定向，或者升级到HttpClient 4。x、 它可以自动处理所有类型的重定向

Answer 4

此外，您还可以使用LaxRedirectStrategy