以Internet Service http://maps.googleapis.com/maps/api/distancematrix/xml?origins=Walldorf&destinations=Berlin為例，

在瀏覽器里訪問這個url，得到輸出：從Walldorf到Berlin的距離。

如何讓一個部署到SAP云平臺的Java應用也能訪問到該internet service呢？

首先在SAP云平臺里創建一個destination，維護service的end point：

在Java代碼里使用SAP云平臺里創建的destination：

然后使用JNDI service讀取destination里配置的url：

部署到SAP云平臺之后，在Eclipse里看到preview結果：

SAP云平臺Cockpit顯示如下：

瀏覽器訪問如下：

web.xml:

<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee"xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"id="WebApp_ID" version="2.5"><!-- Main sample servlet mapped to / so that the integration test harness can detect readiness (generic for all samples) --><servlet><servlet-name>ConnectivityServlet</servlet-name><servlet-class>com.sap.cloud.sample.connectivity.ConnectivityServlet</servlet-class></servlet><servlet-mapping><servlet-name>ConnectivityServlet</servlet-name><url-pattern>/</url-pattern></servlet-mapping><!-- Declare the JNDI lookup of destination --><resource-ref><res-ref-name>connectivityConfiguration</res-ref-name><res-type>com.sap.core.connectivity.api.configuration.ConnectivityConfiguration</res-type></resource-ref> </web-app> package com.sap.cloud.sample.connectivity;import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.net.HttpURLConnection; import java.net.InetSocketAddress; import java.net.Proxy; import java.net.URL;import javax.annotation.Resource; import javax.naming.Context; import javax.naming.InitialContext; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse;import org.slf4j.Logger; import org.slf4j.LoggerFactory;import com.sap.cloud.account.TenantContext; import com.sap.core.connectivity.api.configuration.ConnectivityConfiguration; import com.sap.core.connectivity.api.configuration.DestinationConfiguration;public class ConnectivityServlet extends HttpServlet {@Resourceprivate TenantContext tenantContext;private static final long serialVersionUID = 1L;private static final int COPY_CONTENT_BUFFER_SIZE = 1024;private static final Logger LOGGER = LoggerFactory.getLogger(ConnectivityServlet.class);private static final String ON_PREMISE_PROXY = "OnPremise";@Overridepublic void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {HttpURLConnection urlConnection = null;String destinationName = request.getParameter("destname");if (destinationName == null) {destinationName = "google_map";}try {Context ctx = new InitialContext();ConnectivityConfiguration configuration = (ConnectivityConfiguration) ctx.lookup("java:comp/env/connectivityConfiguration");DestinationConfiguration destConfiguration = configuration.getConfiguration(destinationName);if (destConfiguration == null) {response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR,String.format("Destination %s is not found. Hint:"+ " Make sure to have the destination configured.", destinationName));return;}String value = destConfiguration.getProperty("URL");URL url = new URL(value + "xml?origins=Walldorf&destinations=Paris");String proxyType = destConfiguration.getProperty("ProxyType");Proxy proxy = getProxy(proxyType);urlConnection = (HttpURLConnection) url.openConnection(proxy);injectHeader(urlConnection, proxyType);InputStream instream = urlConnection.getInputStream();OutputStream outstream = response.getOutputStream();copyStream(instream, outstream);} catch (Exception e) {String errorMessage = "Connectivity operation failed with reason: "+ e.getMessage()+ ". See "+ "logs for details. Hint: Make sure to have an HTTP proxy configured in your "+ "local environment in case your environment uses "+ "an HTTP proxy for the outbound Internet "+ "communication.";LOGGER.error("Connectivity operation failed", e);response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR,errorMessage);}}private Proxy getProxy(String proxyType) {Proxy proxy = Proxy.NO_PROXY;String proxyHost = null;String proxyPort = null;if (ON_PREMISE_PROXY.equals(proxyType)) {// Get proxy for on-premise destinationsproxyHost = System.getenv("HC_OP_HTTP_PROXY_HOST");proxyPort = System.getenv("HC_OP_HTTP_PROXY_PORT");} else {// Get proxy for internet destinationsproxyHost = System.getProperty("https.proxyHost");proxyPort = System.getProperty("https.proxyPort");}if (proxyPort != null && proxyHost != null) {int proxyPortNumber = Integer.parseInt(proxyPort);proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress(proxyHost, proxyPortNumber));}return proxy;}private void injectHeader(HttpURLConnection urlConnection, String proxyType) {if (ON_PREMISE_PROXY.equals(proxyType)) {// Insert header for on-premise connectivity with the consumer account nameurlConnection.setRequestProperty("SAP-Connectivity-ConsumerAccount",tenantContext.getTenant().getAccount().getId());}}private void copyStream(InputStream inStream, OutputStream outStream) throws IOException {byte[] buffer = new byte[COPY_CONTENT_BUFFER_SIZE];int len;while ((len = inStream.read(buffer)) != -1) {outStream.write(buffer, 0, len);}} }

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