CoAP协议探究之案列一

本文通过构建一个CoAP的服务端和客户端，来简要了解CoAP协议的消息机制。

一，环境准备

---

1、jdk1.8及以上

2、maven，idea开发工具

二、代码

---

1、服务端

      model包下主要封装服务器要处理的消息信息

package hang.com.model;

import org.eclipse.californium.core.CoapResource;
import org.eclipse.californium.core.server.resources.CoapExchange;

public class CoAPHumidityModel extends CoapResource{

    public CoAPHumidityModel(){
        super("CoAPHumidityModel");

        getAttributes().setTitle("CoAP-Humidity-Model");
    }

    @Override
    public void handleGET(CoapExchange exchange){
        exchange.respond("get humidity: 32%");
    }

    @Override
    public void handlePOST(CoapExchange exchange){
        exchange.respond("post humidity: 45% ");
    }

    @Override
    public void handlePUT(CoapExchange exchange){
        exchange.respond("put humidity: 65% ");
    }

    @Override
    public void handleDELETE(CoapExchange exchange){
        exchange.respond("delete humidity: 67% ");
    }
}

package hang.com.model;

import org.eclipse.californium.core.CoapResource;
import org.eclipse.californium.core.server.resources.CoapExchange;

public class CoAPTemperatureModel  extends CoapResource {

    public CoAPTemperatureModel(){
        //set resource identifier
        super("CoAPTemperatureModel");

        getAttributes().setTitle("Coap-Temperature-Model");
    }

    @Override
    public void handleGET(CoapExchange exchange){
        exchange.respond("get temperature: 21℃");
    }

    @Override
    public void handlePOST(CoapExchange exchange){
        exchange.respond("post temperature: 24℃ ");
    }

    @Override
    public void handlePUT(CoapExchange exchange){
        exchange.respond("put temperature: 27℃ ");
    }

    @Override
    public void handleDELETE(CoapExchange exchange){
        exchange.respond("delete temperature: 21℃ ");
    }
}

服务器端启动代码

package hang.com.server;

import hang.com.model.CoAPHumidityModel;
import hang.com.model.CoAPTemperatureModel;
import org.eclipse.californium.core.CoapResource;
import org.eclipse.californium.core.CoapServer;
import org.eclipse.californium.core.network.CoapEndpoint;
import org.eclipse.californium.core.network.EndpointManager;
import org.eclipse.californium.core.network.config.NetworkConfig;
import org.eclipse.californium.core.server.resources.CoapExchange;

import java.net.Inet4Address;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.SocketException;

public class COAPServerTest extends CoapServer{
    private static final int COAP_PORT = NetworkConfig.getStandard().getInt(NetworkConfig.Keys.COAP_PORT);
    /*
     * Application entry point.
     */
    public static void main(String[] args) {
        try {
            // create server
            COAPServerTest server = new COAPServerTest();
            // add endpoints on all IP addresses
            server.addEndpoints();
            server.start();
        } catch (SocketException e) {
            System.err.println("Failed to initialize server: " + e.getMessage());
        }
    }

    /**
     * Add individual endpoints listening on default CoAP port on all IPv4 addresses of all network interfaces.
     */
    private void addEndpoints() {
        for (InetAddress addr : EndpointManager.getEndpointManager().getNetworkInterfaces()) {
            // only binds to IPv4 addresses and localhost
            if (addr instanceof Inet4Address || addr.isLoopbackAddress()) {
                InetSocketAddress bindToAddress = new InetSocketAddress(addr, COAP_PORT);
                addEndpoint(new CoapEndpoint(bindToAddress));
            }
        }
    }

    /*
     * Constructor for a new Hello-World server. Here, the resources
     * of the server are initialized.
     */
    public COAPServerTest() throws SocketException {
        // provide an instance of a Hello-World resource
        add(new CoAPHumidityModel());
        add(new CoAPTemperatureModel());
    }

}

2、客户端

package hang.com.util;

import org.eclipse.californium.core.CoapClient;
import org.eclipse.californium.core.CoapResponse;

import java.net.URI;
import java.net.URISyntaxException;

public class CoAPUtils {
    public static StringBuffer getCoAPDataInfo(String url)throws URISyntaxException {
        URI uri = new URI(url);
        CoapClient coapClient = new CoapClient(uri);
        CoapResponse resource = coapClient.get();
        StringBuffer buffer = new StringBuffer();
        if(resource != null){
            buffer.append(resource.getCode());
            buffer.append("&");
            buffer.append(resource.getOptions());
            buffer.append("&");
            buffer.append(resource.getResponseText());
            buffer.append("&");
            buffer.append(resource.getPayload());
        }
        return buffer;
    }
}

package hang.com.client;

import hang.com.util.CoAPUtils;

import java.net.URISyntaxException;

public class CoAPClientController {

    private static CoAPUtils coAPUtils;

    public static void main(String[] args)throws URISyntaxException{
        StringBuffer temInfo = coAPUtils.getCoAPDataInfo("coap://127.0.0.1:5683/CoAPTemperatureModel");
        System.out.println(temInfo);
    }
}

       至此，先启动服务器端，然后在客户端执行main方法进行访问。