这是一篇笔记哈，记录怎么在Cordova上使用Java语言的Jar包。

首先，在Plugin中引入jar包，并且定义好target-dir

    <source-file src="src/android/lib/element-connector-1.0.4.jar" target-dir="libs" />
    <source-file src="src/android/lib/californium-core-1.0.4.jar" target-dir="libs" />

接着就可以在代码中使用了，如下是Cordova与CoAP协议的一个简单接口

package com.phodal.plugin.coap;

import org.apache.cordova.*;

import org.json.JSONArray;
import org.json.JSONException;

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

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


public class Coap extends CordovaPlugin {

    @Override
    public boolean execute(String action, JSONArray data, CallbackContext callbackContext) throws JSONException, URISyntaxException {

        if (action.equals("get")) {
            try {
                URI uri = new URI("coap://iot.eclipse.org:5683/");
                CoapClient mCoapClient = new CoapClient(uri);
                CoapResponse response = mCoapClient.get();

                callbackContext.success(response);
                return true;
            } catch (Exception e) {

            }

        } else {
            return false;

        }
    }
}