如何使用HttpURLConnection处理redirect请求呢?

下文笔者讲述使用HttpURLConnection处理Redirect请求的方法分享，如下所示

实现思路:
    通过responseCode的返回状态码进行判断是否需要跳转 

例：
定义后台spring mvc返回跳转状态码页面

@GetMapping("/redirect")
    public ResponseEntity redirect() {
        return ResponseEntity.status(HttpStatus.FOUND).header(HttpHeaders.LOCATION, "http://www.java265.com").build();
    }

HttpURLConnnection捕捉Redirect请求页面

HttpURLConnection connection = (HttpURLConnection) new URL("http://localhost:8080/redirect").openConnection();
connection.setRequestMethod("GET");
//写头文件
connection.setRequestProperty("Content-Type", "application/json");

connection.connect();

//取消自动重定向
connection.setInstanceFollowRedirects(false);

int responseCode = connection.getResponseCode();

log.info("response code : {}", responseCode);

if (responseCode == 302) {
    String location = connection.getHeaderField("Location");
    URLConnection redirect = new URL(location).openConnection();
    redirect.connect();
    // read response
    try (BufferedReader reader = new BufferedReader(new InputStreamReader(redirect.getInputStream()))) {
        String line;
        while ((line = reader.readLine()) != null) {
            System.out.println(line);
        }
    } finally {
        connection.disconnect();
    }
}