在这个例子中，我们将看到如何使用java.net包实用工具，创建一个访问REST服务RESTful的客户端。当然这不是创建一个RESTful客户端最简单的方法，因为你必须自己读取服务器端的响应，以及Json和Java对象的转换。

请求Get

public class JavaNetURLRESTFulClient {

       private static final String targetURL = "http://localhost:8080/JerseyJSONExample/rest/jsonServices/print/Jamie";

       public static void main(String[] args) {

                try {

                     URL restServiceURL = new URL(targetURL);

                     HttpURLConnection httpConnection = (HttpURLConnection) restServiceURL.openConnection();                      httpConnection.setRequestMethod("GET");                      httpConnection.setRequestProperty("Accept", "application/json");

                     if (httpConnection.getResponseCode() != 200) {                             throw new RuntimeException("HTTP GET Request Failed with Error code : "                                           + httpConnection.getResponseCode());                      }

                     BufferedReader responseBuffer = new BufferedReader(new InputStreamReader(                             (httpConnection.getInputStream())));

                     String output;                      System.out.println("Output from Server:  \n");

                     while ((output = responseBuffer.readLine()) != null) {                             System.out.println(output);                      }

                     httpConnection.disconnect();

                } catch (MalformedURLException e) {

                     e.printStackTrace();

                } catch (IOException e) {

                     e.printStackTrace();

                }

              } }

运行后输出结果是：

Output from Server:      {"id":1,"firstName":"Jamie","age":22,"lastName":"Diaz"}

POST提交：

public class JavaNetURLRESTFulClient {

       private static final String targetURL = "http://localhost:8080/JerseyJSONExample/rest/jsonServices/send";

       public static void main(String[] args) {

              try {

                     URL targetUrl = new URL(targetURL);

                     HttpURLConnection httpConnection = (HttpURLConnection) targetUrl.openConnection();                      httpConnection.setDoOutput(true);                      httpConnection.setRequestMethod("POST");                      httpConnection.setRequestProperty("Content-Type", "application/json");

                     String input = "{\"id\":1,\"firstName\":\"Liam\",\"age\":22,\"lastName\":\"Marco\"}";

                     OutputStream outputStream = httpConnection.getOutputStream();                      outputStream.write(input.getBytes());                      outputStream.flush();

                     if (httpConnection.getResponseCode() != 200) {                             throw new RuntimeException("Failed : HTTP error code : "                                    + httpConnection.getResponseCode());                      }

                     BufferedReader responseBuffer = new BufferedReader(new InputStreamReader(                                    (httpConnection.getInputStream())));

                     String output;                      System.out.println("Output from Server:\n");                      while ((output = responseBuffer.readLine()) != null) {                             System.out.println(output);                      }

                     httpConnection.disconnect();

                } catch (MalformedURLException e) {

                     e.printStackTrace();

                } catch (IOException e) {

                     e.printStackTrace();

               }

              }      }