js对Map的操作（可作为工具类）

function Map() {   
    /** 存放键的数组(遍历用到) */  
    this.keys = new Array();   
    /** 存放数据 */  
    this.data = new Object();   
    /**  
     * 放入一个键值对  
     * @param {String} key  
     * @param {Object} value  
     */  
    this.put = function(key, value) {   
        if(this.data[key] == null){   
            this.keys.push(key);   
        }   
        this.data[key] = value;   
    };   
    /**  
     * 获取某键对应的值  
     * @param {String} key  
     * @return {Object} value  
     */  
    this.get = function(key) {   
        return this.data[key];   
    };   
    /**  
     * 删除一个键值对  
     * @param {String} key  
     */  
    this.remove = function(key) {   
        this.keys.remove(key);   
        this.data[key] = null;   
    };   
    /**  
     * 遍历Map,执行处理函数  
     *   
     * @param {Function} 回调函数 function(key,value,index){..}  
     */  
    this.each = function(fn){   
        if(typeof fn != 'function'){   
            return;   
        }   
        var len = this.keys.length;   
        for(var i=0;i<len;i++){   
            var k = this.keys[i];   
            fn(k,this.data[k],i);   
        }   
    };   
    /**  
     * 获取键值数组(类似Java的entrySet())  
     * @return 键值对象{key,value}的数组  
     */  
    this.entrys = function() {   
        var len = this.keys.length;   
        var entrys = new Array(len);   
        for (var i = 0; i < len; i++) {   
            entrys[i] = {   
                key : this.keys[i],   
                value : this.data[i]   
            };   
        }   
        return entrys;   
    };   
    /**  
     * 判断Map是否为空  
     */  
    this.isEmpty = function() {   
        return this.keys.length == 0;   
    };   
    /**  
     * 获取键值对数量  
     */  
    this.size = function(){   
        return this.keys.length;   
    };   
    /**  
     * 重写toString   
     */  
    this.toString = function(){   
        var s = "{";   
        for(var i=0;i<this.keys.length;i++,s+=','){   
            var k = this.keys[i];   
            s += k+"="+this.data[k];   
        }   
        s+="}";   
        return s;   
    };   
}   

//测试效果
function testMap(){   
    var m = new Map();   
    m.put('key1','Comtop');   
    m.put('key2','测试2');   
    m.put('key3','测试3');   
    alert("init:"+m);   
       
    m.put('key1','测试测试');   
    alert("set key1:"+m);   
       
    m.remove("key2");   
    alert("remove key2: "+m);   
       
    var s ="";   
    m.each(function(key,value,index){   
        s += index+":"+ key+"="+value+"/n";   
    });   
    alert(s);   
}