JS高效关键字搜索转

原文地址: http://www.cnblogs.com/index-html/archive/2013/04/17/js_keyword_match.html

重点关注评论中的代码..

var treeSearch = {

    makeTree: function(strKeys) {

        "use strict";

        var tblCur = {},

            tblRoot,

            key,

            str_key,

            Length,

            j,

            i

            ;

        tblRoot = tblCur;

        for ( j = strKeys.length - 1; j >= 0; j -= 1) {

            str_key = strKeys[j];

            Length = str_key.length;

            for ( i = 0; i < Length; i += 1) {

                key = str_key.charAt(i);

                if (tblCur.hasOwnProperty(key)) { //生成子节点 

                    tblCur = tblCur[key];

                } else {

                    tblCur = tblCur[key] = {};

                }

            }

            tblCur.end = true; //最后一个关键字没有分割符

            tblCur = tblRoot;

        }

        return tblRoot;

    },

    search: function(content, tblRoot) {

        "use strict";

        var tblCur,

            p_star = 0,

            n = content.length,

            p_end,

            match,  //是否找到匹配

            match_key,

            match_str,

            arrMatch = [],  //存储结果

            arrLength = 0   //arrMatch的长度索引

            ;

  

        while (p_star < n) {

            tblCur = tblRoot; //回溯至根部

            p_end = p_star;

            match_str = "";

            match = false;

            do {

                match_key = content.charAt(p_end);

                if (!(tblCur = tblCur[match_key])) { //本次匹配结束

                    p_star += 1;

                    break;

                }else{

                    match_str += match_key;

                }

                p_end += 1;

                if (tblCur.end === true) //是否匹配到尾部  //找到匹配关键字

                {

                    match = true;

                }

            } while (true);

  

            if (match === true) { //最大匹配

                arrMatch[arrLength] = { //增强可读性

                    key: match_str,

                    begin: p_star - 1,

                    end: p_end

                };

                arrLength += 1;

                p_star = p_end;

            }

        }

        return arrMatch;

    }

};

使用实例：

View Code?

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function test(strContent, strKeys) {     var arrMatch,         tblRoot = treeSearch.makeTree(strKeys),         t = new Date();           arrMatch = treeSearch.search(strContent, tblRoot);        console.log("time is: " + (new Date() - t) + "mm");        console.log(arrMatch); } var s = (function() {     var Things = [' ', '\n', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'];     var s = "";     for (var i = 1000000; i >= 0; i--) {         s += Things[parseInt(Math.random() * Things.length) % Things.length]     };     return s; })() test(s, ["abc", "efge", "fun", "tree"]);