从零开始学习Node.js系列教程四：多页面实现的数学运算示例

本文实例讲述了Node.js多页面实现的数学运算。分享给大家供大家参考，具体如下：

app-node.js

var http_port = 3000;
var http = require('http');
var htutil = require('./htutil');
var server = http.createServer(function(req, res){
  htutil.loadParams(req, res, undefined);
  if (req.requrl.pathname === '/'){
    require('./home-node').get(req, res);
  }else if (req.requrl.pathname === '/square'){
    require('./square-node').get(req, res);
  }else if (req.requrl.pathname === '/factorial'){
    require('./factorial-node').get(req, res);
  }else if (req.requrl.pathname === '/fibonacci'){
    require('./fibo-node').get(req, res);
  }else if (req.requrl.pathname === '/mult'){
    require('./mult-node').get(req, res);
  }else{
    res.writeHead(404, {'Content-Type': 'text/plain'});
    res.end("bad URL" + req.url);
  }
});
server.listen(http_port);
console.log('listening to http://localhost:3000');

htutil.js

var url = require('url');
exports.loadParams = function(req, res, next){
  req.requrl = url.parse(req.url, true);
  req.a = (req.requrl.query.a && !isNaN(req.requrl.query.a))
    ? new Number(req.requrl.query.a)
    : NaN;
  req.b = (req.requrl.query.b && !isNaN(req.requrl.query.b))
    ? new Number(req.requrl.query.b)
    : NaN;
  if(next) next();
}
exports.navbar = function(){
  return ["<div class='navbar'>",
    "<p><a href='/'>home</a></p>",
    "<p><a href='/mult'>Multiplication</a></p>",
    "<p><a href='/square'>Square</a></p>",
    "<p><a href='/factorial'>Factorial</a></p>",
    "<p><a href='/fibonacci'>Fibonacci</a></p>",
    "</div>"].join('\n');
}
exports.page = function(title, navbar, content){
  return ["<html><head><title>{title}</title></head>",
    "<body><h1>{title}</h1>",
    "<table><tr>",
    "<td>{navbar}</td><td>{content}</td>",
    "</tr></table></body></html>"
    ].join('\n')
    .replace(new RegExp("{title}", "gm"), title)
    .replace("{navbar}", navbar)
    .replace("{content}", content);
}

home-node.js

var htutil = require('./htutil');
exports.get = function(req, res){
  res.writeHead(200, {'Content-Type': 'text/html'});
  res.end(htutil.page("Math Wizard", htutil.navbar(), "<p>Math Wizard</p>"));
}

square-node.js

var htutil = require('./htutil');
exports.get = function(req, res){
  res.writeHead(200, {'Content-Type': 'text/html'});
  var result = req.a * req.a;
  res.end(
    htutil.page("Square", htutil.navbar(), [
      (!isNaN(req.a) ?
        ("<p class='result'>{a} squared = {sq}</p>"
          .replace("{a}", req.a)
          .replace("{sq}", req.a * req.a))
        : ""),
      "<p>Enter numbers to see its square</p>",
      "<form name='square' action='/square' method='get'>",
      "A: <input type='text' name='a' /><br/>",
      "<input type='submit' value='Submit' />",
      "</form>"
    ].join('\n'))
  );
}

factorial-node.js

var htutil = require('./htutil');
var math = require('./math');
exports.get = function(req, res){
  res.writeHead(200, {'Content-Type': 'text/html'});
  res.end(
    htutil.page("Factorial", htutil.navbar(), [
      (!isNaN(req.a) ?
        ("<p class='result'>{a} factorial = {fact}</p>"
          .replace("{a}", req.a)
          .replace("{fact}", math.factorial(Math.floor(req.a))))
        : ""),
      "<p>Enter numbers to see its factorial</p>",
      "<form name='factorial' action='/factorial' method='get'>",
      "A: <input type='text' name='a' /><br/>",
      "<input type='submit' value='Submit' />",
      "</form>"
    ].join('\n'))
  );
}

mult-node.js

var htutil = require('./htutil');
exports.get = function(req, res){
  res.writeHead(200, {'Content-Type': 'text/html'});
  var result = req.a * req.b;
  res.end(
    htutil.page("Multiplication", htutil.navbar(), [
      (!isNaN(req.a) && !isNaN(req.b) ?
        ("<p class='result'>{a} * {b} = {result}</p>"
          .replace("{a}", req.a)
          .replace("{b}", req.b)
          .replace("{result}", req.a * req.b))
        : ""),
      "<p>Enter numbers to mutiply</p>",
      "<form name='mult' action='/mult' method='get'>",
      "A: <input type='text' name='a' /><br/>",
      "B: <input type='text' name='b' /><br/>",
      "<input type='submit' value='Submit' />",
      "</form>"
    ].join('\n'))
  );
}

fibo-node.js

var htutil = require('./htutil');
var math = require('./math');
exports.get = function(req, res){
  res.writeHead(200, {'Content-Type': 'text/html'});
  res.end(
    htutil.page("Fibonacci", htutil.navbar(), [
      (!isNaN(req.a) ?
        ("<p class='result'>{a} fibonacci = {fibo}</p>"
          .replace("{a}", Math.floor(req.a))
          .replace("{fibo}", math.fibonacci(Math.floor(req.a))))
        : ""),
      "<p>Enter numbers to see its fibonacci</p>",
      "<form name='fibonacci' action='/fibonacci' method='get'>",
      "A: <input type='text' name='a' /><br/>",
      "<input type='submit' value='Submit' />",
      "</form>"
    ].join('\n'))
  );
}

fibo2-node.js

var htutil = require('./htutil');
var math = require('./math');
function sendResult(req, res, a, fiboval){
  res.writeHead(200, {'Content-Type': 'text/html'});
  res.end(
    htutil.page("Fibonacci", htutil.navbar(), [
      (!isNaN(fiboval) ?
        ("<p class='result'>{a} fibonacci = {fibo}</p>"
          .replace("{a}", a)
          .replace("{fibo}", fiboval))
        : ""),
      "<p>Enter numbers to see its fibonacci</p>",
      "<form name='fibonacci' action='/fibonacci' method='get'>",
      "A: <input type='text' name='a' /><br/>",
      "<input type='submit' value='Submit' />",
      "</form>"
    ].join('\n'))
  );
}
exports.get = function(req, res){
  if (!isNaN(req.a)){
    math.fibonacciAsync(Math.floor(req.a), function(val){
      sendResult(req, res, Math.floor(req.a) ,val);
    });
  }else {
    sendResult(req, res, NaN, NaN);
  }
}

math.js

var factorial = exports.factorial = function(n){
  if (n == 0)
    return 1;
  else
    return n * factorial(n-1);
}
var fibonacci = exports.fibonacci = function(n){
  if (n === 1)
    return 1;
  else if (n === 2)
    return 1;
  else
    return fibonacci(n-1) + fibonacci(n-2);
}
var fibonacciAsync = exports.fibonacciAsync = function(n, done){
  if (n ==1 || n == 2)
    done(1);
  else {
    process.nextTick(function(){
      fibonacciAsync(n-1, function(val1){
        process.nextTick(function(){
          fibonacciAsync(n-2, function(val2){
            done(val1 + val2);
          });
        })
      });
    });
  }
}

希望本文所述对大家nodejs程序设计有所帮助。