var http = require("http");

//1.引入 http 模块
var http=require('http');
//2.用 http 模块创建服务
http.createServer(function(req,res){
// 发送 HTTP 头部
// HTTP 状态值: 200 : OK
//设置 HTTP 头部，状态码是 200，文件类型是 html，字符集是 utf-8
res.writeHead(200,{"Content-Type":"text/html;charset='utf-8'"});
res.write('你好 nodejs');
res.write('我是第一个 nodejs 程序');
res.end(); /*结束响应*/
}).listen(8001);

node start

module.exports = (function () {
 
  "use strict";
 
  console.time('[HttpServer][Start]');
 
  //http协议模块
  var http = require('http');
  //url解析模块
  var url = require('url');
  //文件系统模块
  var fs = require("fs");
  //路径解析模块
  var path = require("path");
 
  return {
    //启动服务
    start: function () {
      var port = this.config.port;
      var ip = this.config.ip;
 
      //创建一个服务
      var httpServer = http.createServer(this.processRequest.bind(this));
 
      //在指定的端口监听服务
      httpServer.listen(port, function () {
        console.log("[HttpServer][Start]", "runing at http://" + ip + ":" + port + "/");
        console.timeEnd("[HttpServer][Start]");
      });
 
      httpServer.on("error", function (error) {
        console.error(error);
      });
    },
 
    /**
     * 请求处理
     * @param request
     * @param response
     */
    processRequest: function (request, response) {
      var hasExt = true;
      var requestUrl = request.url;
      var pathName = url.parse(requestUrl).pathname;
 
      //对请求的路径进行解码，防止中文乱码
      pathName = decodeURI(pathName);
 
      //如果路径中没有扩展名
      if ((pathName) === '') {
        //如果不是以/结尾的，加/并作301重定向
        if (pathName.charAt(pathName.length - 1) != "/") {
          pathName += "/";
          var redirect = "http://" + request.headers.host + pathName;
          response.writeHead(301, {
            location: redirect
          });
          response.end();
          return; //fix bug: 执行301重定向后应终止后续流程，以防 "write after end" 异常
        }
        //添加默认的访问页面,但这个页面不一定存在,后面会处理
        pathName += "index.html";
        hasExt = false; //标记默认页面是程序自动添加的
      }
 
      //获取资源文件的相对路径
      var filePath = path.join("http/webroot", pathName);
 
      //获取对应文件的文档类型
      var contentType = this.getContentType(filePath);
 
      //如果文件名存在
      fs.exists(filePath, function (exists) {
        if (exists) {
          response.writeHead(200, {"content-type": contentType});
          var stream = fs.createReadStream(filePath, {flags: "r", encoding: null});
          stream.on("error", function () {
            response.writeHead(500, {"content-type": "text/html"});
            response.end("
500 Server Error
");
          });
          //返回文件内容
          stream.pipe(response);
        } else { //文件名不存在的情况
          if (hasExt) {
            //如果这个文件不是程序自动添加的，直接返回404
            response.writeHead(404, {"content-type": "text/html"});
            response.end("
404 Not Found
");
          } else {
            //如果文件是程序自动添加的且不存在，则表示用户希望访问的是该目录下的文件列表
            var html = "";
 
            try {
              //用户访问目录
              var filedir = filePath.substring(0, filePath.lastIndexOf('\\'));
              //获取用户访问路径下的文件列表
              var files = fs.readdirSync(filedir);
              //将访问路径下的所以文件一一列举出来，并添加超链接，以便用户进一步访问
              for (var i in files) {
                var filename = files[i];
                html += "
" + filename + "
";
              }
            } catch (e) {
              html += "
您访问的目录不存在
"
            }
            response.writeHead(200, {"content-type": "text/html"});
            response.end(html);
          }
        }
      });
    },
 
    /**
     * 获取文档的内容类型
     * @param filePath
     * @returns {*}
     */
    getContentType: function (filePath) {
      var contentType = this.config.mime;
      var ext = path.extname(filePath).substr(1);
      if (contentType.hasOwnProperty(ext)) {
        return contentType[ext];
      } else {
        return contentType.default;
      }
    },
 
    ///配置信息
    config: {
      port: 8888,
      ip: '127.0.0.1',
      mime: {
        html: "text/html",
        js: "text/javascript",
        css: "text/css",
        gif: "image/gif",
        jpg: "image/jpeg",
        png: "image/png",
        ico: "image/icon",
        txt: "text/plain",
        json: "application/json",
        default: "application/octet-stream"
      }
    }
  }
})();

var http = require('./http/HttpServer');
http.start();