HttpClient只是模擬一次tcp請求，瀏覽器則會幫你處理重定向、快取等事情。這也就是為什麼用瀏覽器表單post提交後，不管服務端如何重定向，都能正常接收到服務端返回的資料。

       但是用HttpClient呢，你會發現，請求後，會返回302，因為POST方式提交HttpClient是不會幫你處理重定向的。

       方法一：（自己手動處理）

        HttpClient httpClient = HttpClients.createDefault();

        HttpPost httpPost= new HttpPost(http://ip:sport/xxx);

        CloseableHttpResponse response = httpclient.execute(httpPost);

        int statusCode = response.getStatusLine().getStatusCode();
        System.out.println("statusCode=="+statusCode); //返回碼

        Header header=response.getFirstHeader("Location");

        //重定向地址
        String location =  header.getValue();
        System.out.println(location);

        //然後再對新的location發起請求即可

        HttpGet httpGet = new HttpGet(location);
        CloseableHttpResponse response2 = httpclient.execute(httpGet);
        System.out.println("返回報文"+EntityUtils.toString(response2.getEntity(), "UT-F-8"));

       方法二：（已有工具類）

       HttpClientBuilder builder = HttpClients.custom()
            .disableAutomaticRetries() //關閉自動處理重定向
            .setRedirectStrategy(new LaxRedirectStrategy());//利用LaxRedirectStrategy處理POST重定向問題

       CloseableHttpClient client = builder.build();

        HttpPost httpPost= new HttpPost(http://ip:sport/xxx);

        CloseableHttpResponse response = client.execute(httpPost);

        int statusCode = response.getStatusLine().getStatusCode();
        System.out.println("statusCode=="+statusCode); //返回碼

         System.out.println("返回報文"+EntityUtils.toString(response.getEntity(), "UT-F-8"));