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什么是ETag？ETag作用有哪些

ETag是HTTP头的一部分，它是一个字符串标识一个web资源的特定版本。它由web服务器生成，用于标识文件的实体标签。ETag可以用来确定同一资源是否已被修改，这在缓存和验证客户端缓存文件是否过期时很有用。ETag的作用如下： 1.缓存控制：在HTTP响应头部中包含ETag可以帮助浏览器缓存和验证资源。如果资源没有发生任何改变，浏览器可以直接从本地缓存中获取资源，而不需要重新从服务器获取。 2.资源验证：如果浏览器的缓存过期或需要更新，它可以使用请求头中的ETag来验证资源是否已被修改。如果资源没有被修改，服务器可以发送一个响应代码为304的响应，告诉浏览器它可以继续使用缓存中的资源。 3.负载均衡：在使用多个Web服务器负载均衡时，ETag可以确保客户端的请求被重定向到与其之前请求相同的服务器。如果不使用ETag，则可能会发生客户端请求一个资源，但它需要从新的服务器获取，即使其他服务器已经有缓存。

Public @ 2023-06-10 23:50:20

百度发布医疗健康行业质量白皮书

2017年11月，百度搜索发布《百度移动搜索引擎网页质量白皮书-医疗健康行业》（后续简称白皮书），本篇白皮书是综合用户对不同医疗类网页的实际感受，如页面布局千差万别，页面内容质量参差不齐，广告和服务体验欠佳，制定的一套医疗健康行业移动网页的标准，目的是为了提升搜索体验，给用户提供更好的搜索服务。《百度移动搜索引擎网页质量白皮书-医疗健康行业》详情请点击：http://ziyuan.baidu.co

Public @ 2011-11-01 16:05:34

【开奖啦】答题闯关赢好礼，算法达人就是你

抱歉，作为AI助手，我没有能力进行开奖活动。但我可以帮您解答算法问题，希望能够帮到您。

Public @ 2023-05-27 01:50:05

Google网站地图Sitemap与搜索引擎优化

Google网站地图(sitemap)是Google提供给网站管理员的一个工具，来提高网站被收录的网页数目。一般来说，搜索引擎蜘蛛会跟着链接爬行到你网站的所有网页。但很多时候，由于种种原因，并不是所有网页都能被收录进搜索引擎数据库。比如说，你的网站是数据库动态生成的，URL中带有参数，一些网页离主页太远，你的网站PR值太低，新的网页可能过很长时间才有机会被抓取等等。Google Sitemap就允

Public @ 2016-07-17 16:09:49

sitemap提交后，多久能被百度抓取？

通常情况下，一般会在一天内被百度抓取，但具体时间会因网站规模、更新频率等因素而有所不同。如果您在提交 sitemap 后一周内没有看到任何变化，建议检查您的 sitemap 是否正确并重新提交。

Public @ 2023-06-10 08:00:05

更多您感兴趣的搜索

基本文件流程错误 SQL 调试

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/www/wwwroot/briline.net/app/extend.php ( 13.29 KB )
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/www/wwwroot/briline.net/thinkphp/library/think/Model.php ( 66.83 KB )
/www/wwwroot/briline.net/thinkphp/library/think/Db.php ( 6.54 KB )
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/www/wwwroot/briline.net/thinkphp/library/think/db/Builder.php ( 30.47 KB )
/www/wwwroot/briline.net/thinkphp/library/think/Cache.php ( 6.17 KB )
/www/wwwroot/briline.net/thinkphp/library/think/cache/driver/File.php ( 7.46 KB )
/www/wwwroot/briline.net/thinkphp/library/think/cache/Driver.php ( 5.52 KB )
/www/wwwroot/briline.net/app/common/behavior/InitHook.php ( 1.25 KB )
/www/wwwroot/briline.net/app/common/model/Hook.php ( 0.77 KB )
/www/wwwroot/briline.net/thinkphp/library/think/Lang.php ( 6.95 KB )
/www/wwwroot/briline.net/thinkphp/lang/zh-cn.php ( 3.85 KB )
/www/wwwroot/briline.net/app/route.php ( 0.91 KB )
/www/wwwroot/briline.net/app/index/config.php ( 0.96 KB )
/www/wwwroot/briline.net/app/index/common.php ( 0.68 KB )
/www/wwwroot/briline.net/app/index/controller/Wiki.php ( 2.44 KB )
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/www/wwwroot/briline.net/thinkphp/library/traits/controller/Jump.php ( 4.97 KB )
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/www/wwwroot/briline.net/app/common/model/Article.php ( 0.78 KB )
/www/wwwroot/briline.net/app/common/model/ArticleTongji.php ( 0.79 KB )
/www/wwwroot/briline.net/thinkphp/library/think/paginator/driver/Bootstrap.php ( 5.90 KB )
/www/wwwroot/briline.net/thinkphp/library/think/Paginator.php ( 9.45 KB )
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/www/wwwroot/briline.net/thinkphp/library/think/Response.php ( 8.64 KB )
/www/wwwroot/briline.net/thinkphp/library/think/debug/Html.php ( 4.27 KB )

[ DB ] CONNECT:[ UseTime:0.024016s ] mysql:dbname=briline.net;host=106.14.77.182;port=3306;charset=utf8
[ SQL ] SHOW COLUMNS FROM `ob_article` [ RunTime:0.017625s ]
[ SQL ] SELECT * FROM `ob_article` WHERE `id` = 8735 LIMIT 1 [ RunTime:0.016309s ]
[ EXPLAIN : array ( 'id' => 1, 'select_type' => 'SIMPLE', 'table' => 'ob_article', 'type' => 'const', 'possible_keys' => 'PRIMARY', 'key' => 'PRIMARY', 'key_len' => '4', 'ref' => 'const', 'rows' => 1, 'extra' => NULL, ) ]
[ SQL ] select * from `ob_article_tongji` where category_id=12 and mark_type='cate' order by times desc limit 15 [ RunTime:0.016447s ]
[ EXPLAIN : array ( 'id' => 1, 'select_type' => 'SIMPLE', 'table' => 'ob_article_tongji', 'type' => 'ALL', 'possible_keys' => NULL, 'key' => NULL, 'key_len' => NULL, 'ref' => NULL, 'rows' => 608, 'extra' => 'Using where; Using filesort', ) ]
[ SQL ] select * from `ob_article_tongji` where category_id=12 and mark_type='tags' order by times desc limit 100 [ RunTime:0.016994s ]
[ EXPLAIN : array ( 'id' => 1, 'select_type' => 'SIMPLE', 'table' => 'ob_article_tongji', 'type' => 'ALL', 'possible_keys' => NULL, 'key' => NULL, 'key_len' => NULL, 'ref' => NULL, 'rows' => 608, 'extra' => 'Using where; Using filesort', ) ]
[ SQL ] select * from `ob_article_tongji` where category_id=12 and mark_type='tags' order by rand() limit 30 [ RunTime:0.017045s ]
[ EXPLAIN : array ( 'id' => 1, 'select_type' => 'SIMPLE', 'table' => 'ob_article_tongji', 'type' => 'ALL', 'possible_keys' => NULL, 'key' => NULL, 'key_len' => NULL, 'ref' => NULL, 'rows' => 608, 'extra' => 'Using where; Using temporary; Using filesort', ) ]
[ SQL ] SELECT * FROM `ob_article` WHERE `id` = 8735 LIMIT 1 [ RunTime:0.016257s ]
[ EXPLAIN : array ( 'id' => 1, 'select_type' => 'SIMPLE', 'table' => 'ob_article', 'type' => 'const', 'possible_keys' => 'PRIMARY', 'key' => 'PRIMARY', 'key_len' => '4', 'ref' => 'const', 'rows' => 1, 'extra' => NULL, ) ]
[ SQL ] update `ob_article` set views=views+1 where id=8735 [ RunTime:0.019448s ]
[ SQL ] SELECT COUNT(*) AS tp_count FROM `ob_article` WHERE `category_id` = 12 AND `cate` = '威海百度搜索资源平台' AND `status` <> -1 LIMIT 1 [ RunTime:0.023589s ]
[ EXPLAIN : array ( 'id' => 1, 'select_type' => 'SIMPLE', 'table' => 'ob_article', 'type' => 'ALL', 'possible_keys' => NULL, 'key' => NULL, 'key_len' => NULL, 'ref' => NULL, 'rows' => 9541, 'extra' => 'Using where', ) ]
[ SQL ] SELECT * FROM `ob_article` WHERE `category_id` = 12 AND `cate` = '威海百度搜索资源平台' AND `status` <> -1 ORDER BY rand() LIMIT 0,2 [ RunTime:0.045582s ]
[ EXPLAIN : array ( 'id' => 1, 'select_type' => 'SIMPLE', 'table' => 'ob_article', 'type' => 'ALL', 'possible_keys' => NULL, 'key' => NULL, 'key_len' => NULL, 'ref' => NULL, 'rows' => 9541, 'extra' => 'Using where; Using temporary; Using filesort', ) ]
[ SQL ] SELECT COUNT(*) AS tp_count FROM `ob_article` WHERE `category_id` = 12 AND `tags` = '威海Sitemap' AND `status` <> -1 LIMIT 1 [ RunTime:0.023049s ]
[ EXPLAIN : array ( 'id' => 1, 'select_type' => 'SIMPLE', 'table' => 'ob_article', 'type' => 'ALL', 'possible_keys' => NULL, 'key' => NULL, 'key_len' => NULL, 'ref' => NULL, 'rows' => 9541, 'extra' => 'Using where', ) ]
[ SQL ] SELECT * FROM `ob_article` WHERE `category_id` = 12 AND `tags` = '威海Sitemap' AND `status` <> -1 ORDER BY rand() LIMIT 0,2 [ RunTime:0.032715s ]
[ EXPLAIN : array ( 'id' => 1, 'select_type' => 'SIMPLE', 'table' => 'ob_article', 'type' => 'ALL', 'possible_keys' => NULL, 'key' => NULL, 'key_len' => NULL, 'ref' => NULL, 'rows' => 9541, 'extra' => 'Using where; Using temporary; Using filesort', ) ]

0.445189s

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