摘要：以，在瀏覽器里訪問這個，得到輸出從到的距離。如何讓一個部署到云平臺的應用也能訪問到該呢首先在云平臺里創建一個，維護的在代碼里使用云平臺里創建的然后使用讀取里配置的部署到云平臺之后，在里看到結果云平臺顯示如下瀏覽器訪問如下

以Internet Service http://maps.googleapis.com/ma...，

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:

    
    
        ConnectivityServlet
        com.sap.cloud.sample.connectivity.ConnectivityServlet
    
    
        ConnectivityServlet
        /
    

    
    
    connectivityConfiguration
    com.sap.core.connectivity.api.configuration.ConnectivityConfiguration
    

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);
        }
    }
}