java 输入流打印以控制台内容

java httpwebrequest servlets

2022-09-03 04:28:32

sock = new Socket("www.google.com", 80);
       out  = new BufferedOutputStream(sock.getOutputStream());
       in   = new BufferedInputStream(sock.getInputStream());

当我尝试打印出“in”中的内容时，如下所示

 BufferedInputStream bin = new BufferedInputStream(in);
 int b;
 while ( ( b = bin.read() ) != -1 )
 {

     char c = (char)b;         

     System.err.print(""+(char)b); //This prints out content that is unreadable.
                                   //Isn't it supposed to print out html tag?
 }

答案 1

如果要打印网页的内容，则需要使用HTTP协议。您不必自己实现它，最好的方法是使用现有的实现，例如java API HttpURLConnection或Apache的HttpClient。

以下是如何使用HttpURLConnection执行此操作的示例：

URL url = new URL("http","www.google.com");
HttpURLConnection urlc = (HttpURLConnection)url.openConnection();
urlc.setAllowUserInteraction( false );
urlc.setDoInput( true );
urlc.setDoOutput( false );
urlc.setUseCaches( true );
urlc.setRequestMethod("GET");
urlc.connect();
// check you have received an status code 200 to indicate OK
// get the encoding from the Content-Type header
BufferedReader in = new BufferedReader(new InputStreamReader(urlc.getInputStream()));
String line = null;
while((line = in.readLine()) != null) {
  System.out.println(line);
}

// close sockets, handle errors, etc.

如上所述，您可以通过添加接受编码标头并检查响应的内容编码标头来保存流量。

下面是一个 HttpClient 示例，取自此处：

   // Create an instance of HttpClient.
    HttpClient client = new HttpClient();

    // Create a method instance.
    GetMethod method = new GetMethod(url);

    // Provide custom retry handler is necessary
    method.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, 
            new DefaultHttpMethodRetryHandler(3, false));

    try {
      // Execute the method.
      int statusCode = client.executeMethod(method);

      if (statusCode != HttpStatus.SC_OK) {
        System.err.println("Method failed: " + method.getStatusLine());
      }

      // Read the response body.
      byte[] responseBody = method.getResponseBody();

      // Deal with the response.
      // Use caution: ensure correct character encoding and is not binary data
      System.out.println(new String(responseBody));

    } catch (HttpException e) {
      System.err.println("Fatal protocol violation: " + e.getMessage());
      e.printStackTrace();
    } catch (IOException e) {
      System.err.println("Fatal transport error: " + e.getMessage());
      e.printStackTrace();
    } finally {
      // Release the connection.
      method.releaseConnection();
    }

答案 2

使用 Java 8 Stream API 从流创建字符串非常容易：

new BufferedReader(new InputStreamReader(in)).lines().collect(Collectors.joining("\n"))

使用IntelliJ，我甚至可以将这个beeing设置为调试表达式：

我想在Eclipse中，它的工作方式与此类似。