为什么这个正则表达式一执行,就会非常的卡?
问题描述：
目标
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@include file="/WEB-INF/base/include.jsp"%>
<%@ page import="net.bjqfy.civairdef.web.common.constant.CommonConstant" %>
<%String path = request.getContextPath(); %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="X-UA-Compatible" content="IE=8" />
<title><%=CommonConstant.TEST_TITLE_CN%></title>
<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE8" />
<link rel="stylesheet" type="text/css" href="../public/css/style.css">
<link rel="stylesheet" type="text/css" href="../public/jquery-easyui-1.4/themes/default/easyui.css">
<link rel="stylesheet" type="text/css" href="../public/jquery-easyui-1.4/themes/icon.css">
<link rel="stylesheet" href="../public/css/zTreeStyle/zTreeStyle.css" type="text/css"></link>
<script type="text/javascript" src="../public/js/jquery-1.8.0.min.js"></script>
<script type="text/javascript" src="../public/js/upload2.js"></script>
<script type="text/javascript" src="../public/js/jquery.form.js"></script>
<script type="text/javascript" src="../public/jquery-easyui-1.4/jquery.easyui.min.js"></script>
<script type="text/javascript" src="../public/jquery-easyui-1.4/locale/easyui-lang-zh_CN.js"></script>
<script type="text/javascript" src="../public/js/jquery.ztree.core-3.5.js"></script>
<script type="text/javascript" src="../public/js/jquery.ztree.excheck-3.5.js"></script>
<script type="text/javascript" src="../public/js/jquery.ztree.exedit-3.5.js"></script>
<script type="text/javascript" src="../public/js/My97DatePicker/WdatePicker.js"></script>
<script type="text/javascript" src="../public/echarts/echarts.min.js"></script>
</head>
<body leftmargin="0px" topmargin="0" rightmargin="0">
<div id="mainListLayout" style="width: 100%; height: 100%;">
<div data-options="region:'west',title:'日常安全检查'" style="width: 15%;padding-top: 8px;">
<ul id="leftTree"></ul>
</div>
<div id="ctnMain" data-options="region:'center'" style="border:0px; ">
</div>
</div>
</body>
<script type="text/javascript">
$(function(){
initLayout();
initTree();
});
function initLayout(){
$('#mainListLayout').layout();
}
function initTree(){
$('#leftTree').tree({
url:'../every/findTree.do',
onClick:function(node){
showMain(node);
}
});
}
function showMain(node){
if('安全检查信息管理'==node.text){
changMainContext(node,'../every/findInfoMan.do');
}
else if('检查进度图'==node.text){
changMainContext(node,'../every/findProgressMap.do');
}
}
function changMainContext(node,action){
$('#ctnMain').panel({
href:action
});
}
function now(){
var date = new Date();
var year = date.getFullYear();
var month = date.getMonth()+1;
var day = date.getDate();
var hour = date.getHours();
var minute = date.getMinutes();
var second = date.getSeconds();
return year+'-'+month+'-'+day+' '+hour+':'+minute+':'+second;
}
</script>
</html>
正则
(\s*<head>\s*)(.*\s*)*(</head>)
期望结果
<head>
<meta http-equiv="X-UA-Compatible" content="IE=8" />
<title><%=CommonConstant.TEST_TITLE_CN%></title>
<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE8" />
<link rel="stylesheet" type="text/css" href="../public/css/style.css">
<link rel="stylesheet" type="text/css" href="../public/jquery-easyui-1.4/themes/default/easyui.css">
<link rel="stylesheet" type="text/css" href="../public/jquery-easyui-1.4/themes/icon.css">
<link rel="stylesheet" href="../public/css/zTreeStyle/zTreeStyle.css" type="text/css"></link>
<script type="text/javascript" src="../public/js/jquery-1.8.0.min.js"></script>
<script type="text/javascript" src="../public/js/upload2.js"></script>
<script type="text/javascript" src="../public/js/jquery.form.js"></script>
<script type="text/javascript" src="../public/jquery-easyui-1.4/jquery.easyui.min.js"></script>
<script type="text/javascript" src="../public/jquery-easyui-1.4/locale/easyui-lang-zh_CN.js"></script>
<script type="text/javascript" src="../public/js/jquery.ztree.core-3.5.js"></script>
<script type="text/javascript" src="../public/js/jquery.ztree.excheck-3.5.js"></script>
<script type="text/javascript" src="../public/js/jquery.ztree.exedit-3.5.js"></script>
<script type="text/javascript" src="../public/js/My97DatePicker/WdatePicker.js"></script>
<script type="text/javascript" src="../public/echarts/echarts.min.js"></script>
</head>
在客户端的测试工具中可以匹配
但是在Eclipse和正则在线匹配工具中,一执行就会卡死
答
(<head>.*?</head>)
答
试试这句话. 你的正则表达式可能出现了死循环.
(
.*?)试试这句话. 你的正则表达式可能出现了死循环.