简介

Java Californium是一个非常完整的CoAP二方库。
【示例代码仓库】

配置文件

创建一个内存形式配置文件

NetworkConfig config = NetworkConfig.createStandardWithoutFile();

创建一个文件形式配置文件，运行时将在工程根目录下创建一个名为Californium.properties文件。

NetworkConfig config = NetworkConfig.getStandard();

绑定本机所有网卡指定端口

CoapServer server = new CoapServer();
NetworkConfig config = NetworkConfig.createStandardWithoutFile();
for (InetAddress address : EndpointManager.getEndpointManager().getNetworkInterfaces()) {
    InetSocketAddress bindtoAddress = new InetSocketAddress(address, COAP_PORT);
    CoapEndpoint.Builder builder = new CoapEndpoint.Builder();
    builder.setInetSocketAddress(bindtoAddress);
    builder.setNetworkConfig(config);
    server.addEndpoint(builder.build());
} 

最简单的Server

此处使用coapEndpointBuilder.setInetSocketAddress(new InetSocketAddress(COAP_PORT));绑定本机所有网卡的5683端口

package org.iotwuxi.embedded;

import org.eclipse.californium.core.CoapResource;
import org.eclipse.californium.core.CoapServer;
import org.eclipse.californium.core.coap.CoAP;
import org.eclipse.californium.core.network.CoapEndpoint;
import org.eclipse.californium.core.network.config.NetworkConfig;
import org.eclipse.californium.core.server.resources.CoapExchange;
import java.net.InetSocketAddress;


/**
 * @author xukai
 */
public class HelloServer {
    private static final Integer COAP_PORT = NetworkConfig.getStandard().getInt(NetworkConfig.Keys.COAP_PORT);
    public static void main(String[] argv) {
        // 第一步 配置文件
        NetworkConfig networkConfig = NetworkConfig.createStandardWithoutFile();
        // 第二步 创建Endpoint
        CoapEndpoint.Builder coapEndpointBuilder = new CoapEndpoint.Builder();
        coapEndpointBuilder.setNetworkConfig(networkConfig);
        coapEndpointBuilder.setInetSocketAddress(new InetSocketAddress(COAP_PORT));

        // 第三步 创建CoAP服务器 并绑定Endpoint
        CoapServer server = new CoapServer();
        server.addEndpoint(coapEndpointBuilder.build());

        // 增加CoAP资源的快速方法
        server.add(new CoapResource("hello") {
            @Override
            public void handleGET(CoapExchange exchange) {
                exchange.respond(CoAP.ResponseCode.CONTENT, "Hello CoAP!");
            }
        });

        // 增加CoAP资源的常规方法
        server.add(new TimeResource());

        // 最后，启动服务器
        server.start();
    }
}

最简单的Client

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;
import org.eclipse.californium.core.network.CoapEndpoint;
import org.eclipse.californium.core.network.config.NetworkConfig;
import org.eclipse.californium.elements.exception.ConnectorException;

/**
 * @author xukai
 */
public class HelloClient {
    private static final String serverUrl = "coap://127.0.0.1:5683/hello";
    public static void main(String[] args) throws IOException, ConnectorException {

        NetworkConfig networkConfig = NetworkConfig.createStandardWithoutFile();
        CoapEndpoint.Builder coapEndpointBuilder = new CoapEndpoint.Builder();
        coapEndpointBuilder.setNetworkConfig(networkConfig);

        CoapClient client = new CoapClient();
        client.setEndpoint(coapEndpointBuilder.build());
        client.setURI(serverUrl);

        CoapResponse response = client.get();

        if (response != null) {

            System.out.println(response.getCode());
            System.out.println(response.getOptions());
            System.out.println(response.getResponseText());

            System.out.println("\nADVANCED\n");
            System.out.println(Utils.prettyPrint(response));
        } else {
            System.out.println("No response received.");
        }
    }
}