java.net--URL-优快云博客

本文链接：https://blog.youkuaiyun.com/iteye_2259/article/details/81822723

本文详细解释了URI与URL的概念及其区别，并提供了二者互相转换的示例代码。此外，还介绍了如何通过URL进行资源定位及发送POST请求的具体实现。

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URI：统计资源标示。
URL ：统计资源定位符
笼统地说，每个 URL 都是 URI，但不一定每个 URI 都是 URL。这是因为 URI 还包括一个子类，即统一资源名称 (URN)，它命名资源但不指定如何定位资源。

1. Converting Between a URL and a URI URI与URL之间的转化


       URI uri = null;
       URL url = null;
       uri = new URI("file://F:/test.xml");
        // Convert a URI to a URL
       url = uri.toURL();
        // Convert a URL to a URI
       uri =url.toURI();

2. Parsing a URL 解析一个url


      url = new URL("http://localhost:8080/pplive.htm#ppstream");
      String protocol = url.getProtocol(); //http
      String host = url.getHost();         //localhost
      int port = url.getPort();            //8080
      String file = url.getFile();         // /pplive
      String ref = url.getRef();           //ppstream

3. Sending a POST Request Using a URL


      Client:

      String data = URLEncoder.encode("key1","UTF-8")+"="+URLEncoder.encode("value1","UTF-8");
            data += "&"+URLEncoder.encode("key2","UTF-8")+"="+URLEncoder.encode("value2","UTF-8");
            System.out.println(data);

            URL url = new URL("http://127.0.0.1:56231/test/test/");                //切忌不要把应用名称给忘记了
            URLConnection con = url.openConnection();

            //send data
            con.setDoOutput(true);
            con.setDoInput(true);

            OutputStreamWriter writer = new OutputStreamWriter(con.getOutputStream());
            writer.write(data);
            writer.flush();

            //get response
            BufferedReader br = new BufferedReader(new InputStreamReader(con.getInputStream()));
            String line = null;
            while((line = br.readLine()) != null){
                System.out.println(line);
            }
            writer.close();
            br.close();

    Service:

        request.setCharacterEncoding("UTF-8");
        response.setCharacterEncoding("UTF-8");

        BufferedReader br = new BufferedReader(new InputStreamReader(request.getInputStream()));        //这个例子还是有点问题的
        String line = null;
        StringBuilder sb = new StringBuilder();
        while((line = br.readLine()) != null){
            sb.append(line);
        }
        System.out.println(sb.toString());
        PrintWriter pw = new PrintWriter(response.getOutputStream(),true);
        String data = "i'am back !";
        pw.write(data);
        pw.flush();
        pw.close();
        br.close();