如何在Java客戶端呼叫RESTful服務
在這個例子中，我們將看到如何使用java.net包實用工具，建立一個訪問REST服務RESTful的客戶端。當然這不是建立一個RESTful客戶端最簡單的方法，因為你必須自己讀取伺服器端的響應，以及Json和Java物件的轉換。
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();
}
} }
執行後輸出結果是：
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();
}
} }