HTTP Node.js Java API
我正在创建一个Node.js Java后端。 Node.js中间件从Android应用程序接收HTTP请求，然后将其中继到Java代码。 选择此技术的原因是从头开始创建高度可扩展的后端。
我希望Node.js api接收HTTP请求，将其传递给后端的Java端，Java代码进行计算，将结果发送回Node.js API，然后通过发送结果完成该过程回到Android应用程序。
我可以接收和解析HTTP请求：
var BodyParser = require('body-parser'); var Express = require('express'); var JavaClient = require('./NodeJavaBridge.js'); var JavaClientInstance = new JavaClient(); var app = Express(); ///// Receive message logic \\\\\ app.use(BodyParser.json()); app.post('/', function (request, response) { var task = request.body; response.writeHead(200, { 'content-type': 'text/plain' }); var otherObject = { SomeData: 1234 }; var json = JSON.stringify({ data: otherObject }); response.end(json); }); console.log("START --> Java Client Instance"); JavaClientInstance.run(); app.listen(8080); //to port on which the express server listen console.log("Server listening on: " + 8080); 我也可以在Node.js和Java之间发送和接收数据：
var Util = require('util'); var EventEmitter = require('events').EventEmitter; var ChildProc = require('child_process'); var JavaClient = function () { var _self = this; // The child process object we get when we spawn the java process var _javaSpawn = null; // buffer for receiving messages in part and piecing them together later var _receiveBuffer = null; // The location of java and the - we're making these public because maybe // we want to change them in the user of this module. _self.javaPath = 'java'; _self.jarPath = 'C:/Dev/Backend_Java.jar'; _self.verbose = true; // list of events emitted - for informational purposes _self.events = [ 'spawn', 'message', 'exception', 'unknown', 'sent', 'java_error', // Response messages that then become events themselves 'Error', 'Hello', 'Info' ]; /** * Attach our own event handler to reply to the hello message. * This is just a convenience part of the protocol so that clients don't have to do it. * Also connects if connection data was supplied. */ _self.on('Hello', function () { _self.sendHello(); }); /** * Executes the java process to begin sending and receiving communication */ _self.run = function () { // Invoke the process _javaSpawn = ChildProc.spawn(_self.javaPath, ['-jar', _self.jarPath]); // Wire up events _javaSpawn.stdout.on('data', onData); _javaSpawn.stderr.on('data', onJavaError); _javaSpawn.on('exit', function (code) { console.log("The java program exited with code " + code + "."); }); // Emit our own event to indicate to others that we have spawned _self.emit('spawn', _javaSpawn); } // sends the hello request message _self.sendHello = function () { sendMessage( { messageName : 'Hello', version : '1.1' }); } // sends a message that will be echoed back as an Info message _self.sendEcho = function (message) { sendMessage( { messageName : "Echo", message : message }); } // sends a message telling the java app to exit _self.sendGoodbye = function () { sendMessage( { "messageName" : "Goodbye" }); } /** * Sends a message object as a JSON encoded string to the java application for processing. */ function sendMessage(aMsg) { // convert to json and prepare buffer var aJsonString = JSON.stringify(aMsg); var lByteLength = Buffer.byteLength(aJsonString); var lMsgBuffer = new Buffer(4 + lByteLength); // Write 4-byte length, followed by json, to buffer lMsgBuffer.writeUInt32BE(lByteLength, 0); lMsgBuffer.write(aJsonString, 4, aJsonString.length, 'utf8'); // send buffer to standard input on the java application _javaSpawn.stdin.write(lMsgBuffer); _self.emit('sent', aMsg); } /** * Receive data over standard input */ function onData(data) { // Attach or extend receive buffer _receiveBuffer = (null == _receiveBuffer) ? data : Buffer.concat([_receiveBuffer, data]); // Pop all messages until the buffer is exhausted while (null != _receiveBuffer && _receiveBuffer.length > 3) { var size = _receiveBuffer.readInt32BE(0); // Early exit processing if we don't have enough data yet if ((size + 4) > _receiveBuffer.length) { break; } // Pull out the message var json = _receiveBuffer.toString('utf8', 4, (size + 4)); // Resize the receive buffer _receiveBuffer = ((size + 4) == _receiveBuffer.length) ? null : _receiveBuffer.slice((size + 4)); // Parse the message as a JSON object try { var msgObj = JSON.parse(json); // emit the generic message received event _self.emit('message', msgObj); // emit an object-type specific event if ((typeof msgObj.messageName) == 'undefined') { _self.emit('unknown', msgObj); } else { _self.emit(msgObj.messageName, msgObj); } } catch (ex) { _self.emit('exception', ex); } } } /** * Receive error output from the java process */ function onJavaError(data) { _self.emit('java_error', data.toString()); } } // Make our JavaClient class an EventEmitter Util.inherits(JavaClient, EventEmitter); // export our class module.exports = JavaClient;
我的问题：如何让POST请求向我的JavaClient实例发送请求，等待响应然后将其发送回原始（Android应用程序）。
以下是我如何尝试使逻辑工作的示例：
var client = require('./JavaClient'); var instance = new client(); instance.on('message', function(msg) { console.log('Received a message...'); console.log(msg); }); instance.on('sent', function(msg) { console.log('Sent a message...'); console.log(msg); }); instance.on('Info', function(msg) { console.log("Received info"); console.log(msg.message); }); (function() { // Start it up (Hello exchanges happen) instance.run(); // Receive acknowledgement of hello instance.once('Info', function() { // Try echoing something instance.sendEcho("ECHO!"); }); })();
如果我应该更清楚地告诉我（这已经很晚了，我认为我的写作能力正在下降）。 我将不胜感激任何答案/建议/ thisisabadidea类型的评论。
谢谢！
var Util = require('util'); var EventEmitter = require('events').EventEmitter; var ChildProc = require('child_process'); var JavaClient = function () { var _self = this; // The child process object we get when we spawn the java process var _javaSpawn = null; // buffer for receiving messages in part and piecing them together later var _receiveBuffer = null; // The location of java and the - we're making these public because maybe // we want to change them in the user of this module. _self.javaPath = 'java'; _self.jarPath = 'C:/Dev/Backend_Java.jar'; _self.verbose = true; // list of events emitted - for informational purposes _self.events = [ 'spawn', 'message', 'exception', 'unknown', 'sent', 'java_error', // Response messages that then become events themselves 'Error', 'Hello', 'Info' ]; /** * Attach our own event handler to reply to the hello message. * This is just a convenience part of the protocol so that clients don't have to do it. * Also connects if connection data was supplied. */ _self.on('Hello', function () { _self.sendHello(); }); /** * Executes the java process to begin sending and receiving communication */ _self.run = function () { // Invoke the process _javaSpawn = ChildProc.spawn(_self.javaPath, ['-jar', _self.jarPath]); // Wire up events _javaSpawn.stdout.on('data', onData); _javaSpawn.stderr.on('data', onJavaError); _javaSpawn.on('exit', function (code) { console.log("The java program exited with code " + code + "."); }); // Emit our own event to indicate to others that we have spawned _self.emit('spawn', _javaSpawn); } // sends the hello request message _self.sendHello = function () { sendMessage( { messageName : 'Hello', version : '1.1' }); } // sends a message that will be echoed back as an Info message _self.sendEcho = function (message) { sendMessage( { messageName : "Echo", message : message }); } // sends a message telling the java app to exit _self.sendGoodbye = function () { sendMessage( { "messageName" : "Goodbye" }); } /** * Sends a message object as a JSON encoded string to the java application for processing. */ function sendMessage(aMsg) { // convert to json and prepare buffer var aJsonString = JSON.stringify(aMsg); var lByteLength = Buffer.byteLength(aJsonString); var lMsgBuffer = new Buffer(4 + lByteLength); // Write 4-byte length, followed by json, to buffer lMsgBuffer.writeUInt32BE(lByteLength, 0); lMsgBuffer.write(aJsonString, 4, aJsonString.length, 'utf8'); // send buffer to standard input on the java application _javaSpawn.stdin.write(lMsgBuffer); _self.emit('sent', aMsg); } /** * Receive data over standard input */ function onData(data) { // Attach or extend receive buffer _receiveBuffer = (null == _receiveBuffer) ? data : Buffer.concat([_receiveBuffer, data]); // Pop all messages until the buffer is exhausted while (null != _receiveBuffer && _receiveBuffer.length > 3) { var size = _receiveBuffer.readInt32BE(0); // Early exit processing if we don't have enough data yet if ((size + 4) > _receiveBuffer.length) { break; } // Pull out the message var json = _receiveBuffer.toString('utf8', 4, (size + 4)); // Resize the receive buffer _receiveBuffer = ((size + 4) == _receiveBuffer.length) ? null : _receiveBuffer.slice((size + 4)); // Parse the message as a JSON object try { var msgObj = JSON.parse(json); // emit the generic message received event _self.emit('message', msgObj); // emit an object-type specific event if ((typeof msgObj.messageName) == 'undefined') { _self.emit('unknown', msgObj); } else { _self.emit(msgObj.messageName, msgObj); } } catch (ex) { _self.emit('exception', ex); } } } /** * Receive error output from the java process */ function onJavaError(data) { _self.emit('java_error', data.toString()); } } // Make our JavaClient class an EventEmitter Util.inherits(JavaClient, EventEmitter); // export our class module.exports = JavaClient;
var client = require('./JavaClient'); var instance = new client(); instance.on('message', function(msg) { console.log('Received a message...'); console.log(msg); }); instance.on('sent', function(msg) { console.log('Sent a message...'); console.log(msg); }); instance.on('Info', function(msg) { console.log("Received info"); console.log(msg.message); }); (function() { // Start it up (Hello exchanges happen) instance.run(); // Receive acknowledgement of hello instance.once('Info', function() { // Try echoing something instance.sendEcho("ECHO!"); }); })();