javascript实现的查询json实例代码

/*
         * 定义模板函数
        */
        var template = function (queryArr) {
            var count = 0;
            for (var i = 0; i < queryArr.length; i++) {
                var e = queryArr[i];
                if ($express) {
                    count++;
                }
            }
            return count;
        }
        /*
         * 模板创建函数
        */
        var createIntance = function (exp) {
            var fun = template.toString().replace("$express", exp).toString();
            return eval("0," + fun);
        }
        var testTodo = function () {
            var testArr = [
                { name: "张三", age: 20 },
                { name: "李四", age: 25 },
                { name: "王二麻子", age: 28 },
                { name: "小张", age: 30 }
            ];
            var func = createIntance("e.age>=25");
            alert(func(testArr));
        }
        /****************** JS 实现 JSON查询 **********************/</P>
       // 定义常用的函数
        var len = function (s) { return s.length; }
        var left = function (s, n) { return s.substr(0, n); }
        var right = function (s, n) { return s.substr(-n); }
        var index = function (s, find) { return s.indexOf(find) + 1; }
        // 扩展原型方法
        var _proto = Object.prototype;
        // 缓存,解决快速查找
        var _cache = {};
        // 扩展运算符
        var _alias = [
            /@/g, "_e.",
            /AND/gi, "&&",
            /OR/gi, "||",
            /<>/g, "!=",
            /NOT/gi, "!",
            /([^=<>])=([^=]|$)/g, ‘$1==$2‘
        ];
        var _rQuote = /""/g;
        var _rQuoteTemp = /!~/g;
        // 编译
        var _complite = function (code) {
            return eval("0," + code);
        }
        // 将扩展符号转换成标准的JS符号
        var _interpret = function (exp) {
            exp = exp.replace(_rQuote,"!~");
            var arr = exp.split(‘"‘);
            var i, n = arr.length;
            var k = _alias.length;
            for (var i = 0; i < n; i += 2) {
                var s = arr[i];
                for (var j = 0; j < k; j += 2) {
                    if (index(s, _alias[j]) > -1) {
                        s = s.replace(_alias[j], _alias[j + 1]);
                    }
                }
                arr[i] = s;
            }
            for (var i = 1; i < n; i += 2) {
                arr[i] = arr[i].replace(_rQuoteTemp, ‘\\"‘);
            }
            return arr.join(‘"‘);
        }
        // 定义模函数
        var _templ = function (_list) {
            var _ret = [];
            var _i = -1;
            for (var _k in _list) {
                var _e = _list[_k];
                if (_e != _proto[_k]) {
                    if ($C) {
                        _ret[++_i] = _e;
                    }
                }
            }
            return _ret;
        } .toString();
        // 扩展查询的方法
        _proto.Query = function (exp) {
            if (!exp) {
                return [];
            }
            var fn = _cache[exp];
            try {
                if (!fn) {
                    var code = _interpret(exp);
                    code = _templ.replace("$C", code);
                    fn = _cache[exp] = _complite(code);
                }
                return fn(this);
            } catch (e) {
                return [];
            }
        }
        var doTest = function () {
            var heros = [
            // 名============攻=====防=======力量====敏捷=====智力====
                {name: ‘冰室女巫‘, DP: 38, AP: 1.3, Str: 16, Dex: 16, Int: 21 },
                { name: ‘沉默术士‘, DP: 39, AP: 1.1, Str: 17, Dex: 16, Int: 21 },
                { name: ‘娜迦海妖‘, DP: 51, AP: 6.0, Str: 21, Dex: 21, Int: 18 },
                { name: ‘赏金猎人‘, DP: 39, AP: 4.0, Str: 17, Dex: 21, Int: 16 },
                { name: ‘剧毒术士‘, DP: 45, AP: 3.1, Str: 18, Dex: 22, Int: 15 },
                { name: ‘光之守卫‘, DP: 38, AP: 1.1, Str: 16, Dex: 15, Int: 22 },
                { name: ‘炼金术士‘, DP: 49, AP: 0.6, Str: 25, Dex: 11, Int: 25 }
            //...
            ];
            var match = heros.Query(‘@Str>20 AND @Dex>20‘);
            ShowResult(match[0]);</P>
            // 查询：“士”结尾的
            // 结果：沉默术士,剧毒术士,炼金术士
            var match = heros.Query(‘right(@name,1)="士"‘);
            ShowResult(match[0]);
        }
        function ShowResult(result) {
            alert(result.name + " " + result.DP + " " + result.AP + " " + result.Str + " " + result.Dex + " " + result.Int);
        }