nodejs 事件驱动编程例子

色粉盒撒娇

相信nodejs会越来越成功
在学习Nodejs强大有两处: Event-driven, Asynchronous I/O callback.Nodejs服务器发的 程序是单线程方式,这就要求其对于block 类型的I/O要异步处理,而对于计算密集型的代码,也要进行对线程编程,这里简单的写个nodejs Event-driven的小例子.

var events = require('events');
var util = require('util');
// The Thing That Emits Event
Eventer = function(){
events.EventEmitter.call(this);
this.kapow = function(){
var data = "BATMAN";
this.emit('blamo', data);
},
this.bam = function(){
this.emit("boom");
};
};
util.inherits(Eventer, events.EventEmitter);
// The thing that listens to, and handles, those events
Listener = function(){
this.blamoHandler =  function(data){
console.log("** blamo event handled");
console.log(data);
},
this.boomHandler = function(data){
console.log("** boom event handled");
};
};
// The thing that drives the two.
var eventer = new Eventer();
var listener = new Listener(eventer);
eventer.on('blamo', listener.blamoHandler);
eventer.on('boom', listener.boomHandler);
eventer.kapow();
eventer.bam();
/*function add(a, b)
{
console.log('a + b: ' + (a + b) );
}
function sub(a, b)
{
console.log('a - b' + (a - b));
}
add.call(sub, 3, 1);
*/
//result: 4
/*function Class1()
{
this.name = "class1";
this.showNam = function()
{
console.log(this.name);
};
}
function Class2()
{
this.name = "class2";
}
var c1 = new Class1();
var c2 = new Class2();
c1.showNam.call(c2); */
//result: class2
/*function Class1()
{
this.showTxt = function(txt)
{
console.log(txt);
};
}
function Class2()
{
Class1.call(this);
}
var c2 = new Class2();
c2.showTxt("cc");*/
//result: cc.




输出结果:

** blamo event handled
BATMAN
** boom event handled