使用SAP雲平臺 + JNDI訪問Internet Service

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

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

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

首先在SAP雲平臺裡建立一個destination，維護service的end point：

在Java程式碼裡使用SAP雲平臺裡建立的destination：

然後使用JNDI service讀取destination裡配置的url：

部署到SAP雲平臺之後，在Eclipse裡看到preview結果：

SAP雲平臺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 { @Resource private 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"; @Override public 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 destinations proxyHost = System.getenv("HC_OP_HTTP_PROXY_HOST");
            proxyPort = System.getenv("HC_OP_HTTP_PROXY_PORT");
        } else { // Get proxy for internet destinations proxyHost = 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 name urlConnection.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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