在js中实现java中的Map对象 

  1 <html>  
  2 <head>  
  3 <title>Test Map</title>  
  4 <script type="text/javascript">
  5 <!--  
  6   
  7 /**  
  8  * Simple Map  
  9  *   
 10  *   
 11  * var m = new Map();  
 12  * m.put('key','value');  
 13  * ...  
 14  * var s = "";  
 15  * m.each(function(key,value,index){  
 16  *      s += index+":"+ key+"="+value+"/n";  
 17  * });  
 18  * alert(s);  
 19  *   
 20  */  
 21 function Map() {   
 22     /** 存放键的数组(遍历用到) */  
 23     this.keys = new Array();   
 24     /** 存放数据 */  
 25     this.data = new Object();   
 26        
 27     /**  
 28      * 放入一个键值对  
 29      * @param {String} key  
 30      * @param {Object} value  
 31      */  
 32     this.put = function(key, value) {   
 33         if(this.data[key] == null){   
 34             this.keys.push(key);   
 35         }   
 36         this.data[key] = value;   
 37     };   
 38        
 39     /**  
 40      * 获取某键对应的值  
 41      * @param {String} key  
 42      * @return {Object} value  
 43      */  
 44     this.get = function(key) {   
 45         return this.data[key];   
 46     };   
 47        
 48     /**  
 49      * 删除一个键值对  
 50      * @param {String} key  
 51      */  
 52     this.remove = function(key) {   
 53         this.keys.remove(key);   
 54         this.data[key] = null;   
 55     };   
 56        
 57     /**  
 58      * 遍历Map,执行处理函数  
 59      *   
 60      * @param {Function} 回调函数 function(key,value,index){..}  
 61      */  
 62     this.each = function(fn){   
 63         if(typeof fn != 'function'){   
 64             return;   
 65         }   
 66         var len = this.keys.length;   
 67         for(var i=0;i<len;i++){   
 68             var k = this.keys[i];   
 69             fn(k,this.data[k],i);   
 70         }   
 71     };   
 72        
 73     /**  
 74      * 获取键值数组(类似Java的entrySet())  
 75      * @return 键值对象{key,value}的数组  
 76      */  
 77     this.entrys = function() {   
 78         var len = this.keys.length;   
 79         var entrys = new Array(len);   
 80         for (var i = 0; i < len; i++) {   
 81             entrys[i] = {   
 82                 key : this.keys[i],   
 83                 value : this.data[i]   
 84             };   
 85         }   
 86         return entrys;   
 87     };   
 88        
 89     /**  
 90      * 判断Map是否为空  
 91      */  
 92     this.isEmpty = function() {   
 93         return this.keys.length == 0;   
 94     };   
 95        
 96     /**  
 97      * 获取键值对数量  
 98      */  
 99     this.size = function(){   
100         return this.keys.length;   
101     };   
102        
103     /**  
104      * 重写toString   
105      */  
106     this.toString = function(){   
107         var s = "{";   
108         for(var i=0;i<this.keys.length;i++,s+=','){   
109             var k = this.keys[i];   
110             s += k+"="+this.data[k];   
111         }   
112         s+="}";   
113         return s;   
114     };   
115 }   
116   
117   
118 function testMap(){   
119     var m = new Map();   
120     m.put('key1','aaa');   
121     m.put('key2','bbb');   
122     m.put('key3','ccc');   
123     alert("init:"+m);   
124        
125     m.put('key1','aaaxg');   
126     alert("set key1:"+m);   
127        
128     m.remove("key2");   
129     alert("remove key2: "+m);   
130        
131     var s ="";   
132     m.each(function(key,value,index){   
133         s += index+":"+ key+"="+value+"\n";   
134     });   
135     alert(s);   
136 }  
137 //-->
138 </script>
139 </head>  
140 <body>  
141 <input type="button" value="test" onclick="testMap()">  
142 </body>  
143 </html>

 

posted @ 2015-07-22 10:50  JasonK  阅读(1820)  评论(0)    收藏  举报