如何在Java用戶端調用RESTful服務

標籤：

在這個例子中，我們將看到如何使用java.net包工具 + 生產力，建立一個訪問REST服務RESTful的用戶端。當然這不是建立一個RESTful用戶端最簡單的方法，因為你必須自己讀取伺服器端的響應，以及Json和Java對象的轉換。

請求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();

                }

              }
}

運行後輸出結果是：

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();

               }

              }     
}

如何在Java用戶端調用RESTful服務