COAP_HelloWorld

下面我们来利用Californium来编写一个COAP协议的HELLO WORLD程序的服务器端&客户端

你将得到:

通过Californium的jar包来实现一个COAP协议的服务器端&客户端。客户端通过GET请求到服务器端,服务器端响应 hello world.

必需准备:

1.大概15分钟时间。

2.JDK1.8或更高版本

3.Maven3.0+

4.Eclipse

开始构建:

1.在eclipse中创建一个java project。

点击Finish,右键点击工程,转换为maven工程。 

2. 我们编写类COAPServerDemo1来作为COAP服务器。代码如下:

 

package com.stalvan.cf.demo.server;

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

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;


public class COAPServerDemo1 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
            COAPServerDemo1 server = new COAPServerDemo1();
            // 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 COAPServerDemo1() throws SocketException {
        
        // provide an instance of a Hello-World resource
        add(new HelloWorldResource());
    }

    /*
     * Definition of the Hello-World Resource
     */
    class HelloWorldResource extends CoapResource {
        
        public HelloWorldResource() {
            
            // set resource identifier
            super("helloWorld");
            
            // set display name
            getAttributes().setTitle("Hello-World Resource");
        }

        @Override
        public void handleGET(CoapExchange exchange) {
            
            // respond to the request
            exchange.respond("Hello World!");
        }
    }
}


3.client客户端类代码如下:

 

/*******************************************************************************
 * Copyright (c) 2015 Institute for Pervasive Computing, ETH Zurich and others.
 * 
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * and Eclipse Distribution License v1.0 which accompany this distribution.
 * 
 * The Eclipse Public License is available at
 *    http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 *    http://www.eclipse.org/org/documents/edl-v10.html.
 * 
 * Contributors:
 *    Matthias Kovatsch - creator and main architect
 *    Achim Kraus (Bosch Software Innovations GmbH) - add saving payload
 ******************************************************************************/
package com.stalvan.cf.demo.client;

import java.io.FileOutputStream;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;

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


public class COAPClientDemo1 {

	/*
	 * Application entry point.
	 * 
	 */	
	public static void main(String args[]) {
		
		URI uri = null; // URI parameter of the request
		
		if (args.length > 0) {
			
			// input URI from command line arguments
			try {
				uri = new URI(args[0]);
			} catch (URISyntaxException e) {
				System.err.println("Invalid URI: " + e.getMessage());
				System.exit(-1);
			}
			
			CoapClient client = new CoapClient(uri);

			CoapResponse response = client.get();
			
			if (response!=null) {
				
				System.out.println(response.getCode());
				System.out.println(response.getOptions());
				if (args.length > 1) {
					try (FileOutputStream out = new FileOutputStream(args[1])) {
						out.write(response.getPayload());
					} catch (IOException e) {
						e.printStackTrace();
					}
				} else {
					System.out.println(response.getResponseText());
					
					System.out.println(System.lineSeparator() + "ADVANCED" + System.lineSeparator());
					// access advanced API with access to more details through
					// .advanced()
					System.out.println(Utils.prettyPrint(response));
				}
			} else {
				System.out.println("No response received.");
			}
			
		} else {
			// display help
			System.out.println("Californium (Cf) GET Client");
			System.out.println("(c) 2014, Institute for Pervasive Computing, ETH Zurich");
			System.out.println();
			System.out.println("Usage : " + COAPClientDemo1.class.getSimpleName() + " URI [file]");
			System.out.println("  URI : The CoAP URI of the remote resource to GET");
			System.out.println("  file: optional filename to save the received payload");
		}
	}

}


 

4.打开pom.xml加入californium jar的依赖,并下载依赖,代码如下:

 

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>HelloWorldCOAP</groupId>
  <artifactId>HelloWorldCOAP</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <build>
    <sourceDirectory>src</sourceDirectory>
    <plugins>
      <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.3</version>
        <configuration>
          <source>1.8</source>
          <target>1.8</target>
        </configuration>
      </plugin>
    </plugins>
  </build>
  <dependencies>
  	<dependency>
  		<groupId>org.eclipse.californium</groupId>
  		<artifactId>californium-core</artifactId>
  		<version>1.0.4</version>
  	</dependency>
  </dependencies>
</project>

 

5.启动服务器端程序。

在服务器类中 run as java application

6.启动客户端程序

在客户端类中 先点击 run configuration 在程序参数中加入 coap://127.0.0.1:5683/helloWorld

然后运行客户端类,可以看到,请求服务器成功,并得到相应 Hello World!

至此 搭建完毕。如需下载DEMO程序 链接如下:

HelloWorldCOAP版源码下载

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