java - 如何在 HttpClient 中自动重定向(java，apache)

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");

第一次请求(获取)

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。

第二个请求(post):

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;
    }
}

这个响应也是正确的，但我需要重定向到 Headers.Location。

我不知道如何从 Headers Location 获取值或如何自动启用重定向。

Answer 1

由于设计限制，HttpClient 3.x 无法自动处理实体封装请求(例如 POST 和 PUT)的重定向。您要么必须在重定向时手动将 POST 请求转换为 GET，要么升级到 HttpClient 4.x，它可以自动处理所有类型的重定向。