使用SAP云平台 + JNDI访问Internet Service

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

在浏览器里访问这个url，得到输出：从Walldorf到Berlin的距离。

如何让一个部署到SAP云平台的Java应用也能访问到该internet service呢？

首先在SAP云平台里创建一个destination，维护service的end point：

在Java代码里使用SAP云平台里创建的destination：

然后使用JNDI service读取destination里配置的url：

部署到SAP云平台之后，在Eclipse里看到preview结果：

SAP云平台Cockpit显示如下：

浏览器访问如下：

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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使用SAP云平台 + JNDI访问Internet Service

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