欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页

js中实现java中的Map对象 博客分类: web  

程序员文章站 2024-02-07 22:01:22
...
<html>  
<head>  
<title>Test Map</title>  
<script type="text/javascript">
<!--  
  https://www.cnblogs.com/bigtallhcy/p/5586489.html
/**  
 * Simple Map  
 *   
 *   
 * var m = new Map();  
 * m.put('key','value');  
 * ...  
 * var s = "";  
 * m.each(function(key,value,index){  
 *      s += index+":"+ key+"="+value+"/n";  
 * });  
 * alert(s);  
 *   
 */  
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;   
    };   
}   
  
  
function testMap(){   
    var m = new Map();   
    m.put('key1','aaa');   
    m.put('key2','bbb');   
    m.put('key3','ccc');   
    alert("init:"+m);   
       
    m.put('key1','aaaxg');   
    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);   
}  
//-->
</script>
</head>  
<body>  
<input type="button" value="test" onclick="testMap()">  
</body>  
</html>