• mysql 的索引


    1)索引就好比一本书的目录,它能让你更快的找到自己想要的内容。
    2)让获取的数据更有目的性,从而提高数据库检索数据的性能。
    

    1.索引的类型

    1)BTREE:B+树索引   				(Btree  B+tree B*tree)
    2)HASH:HASH索引 hash key
    3)FULLTEXT:全文索引
    4)RTREE:R树索引
    

    ​ Btree索引

    比如 我要搜索一个数字 38   这时要走3次IO
          然后在搜索一个>38 <70 的数字 这时要走9次IO
    

    ​ B+tree算法

    比如 我要搜索一个数字 38   这时要走3次IO
          然后在搜索一个>38 <70 的数字 这时要走6次IO  注意 他是不走指针的 里面的Q代表指针
          
          
    好处:1。优化了范围查询
         2.在叶子节点添加了相邻节点的指针
          
       
    

    ​ B*tree

    比如 我要搜索一个数字 38   这时要走3次IO
    然后在搜索一个>38 <70 的数字 这时要走2次IO  注意 他是不走指针的 里面的Q代表指针
     而且他只在枝节点上找 
    好处:在枝节点添加了相邻 节点的指针
    

    2.索引管理

    1.索引必须添加在列上面
    
    2.在where后面接上建立索引的列,会加快查询速度
    
    3.pages<---索引(属性)<----查数据。
    

    3.索引的分类

    主键索引(primary key)
    普通索引 ***(key)
    唯一索引(unique key)
    

    4.添加索引

    1普通索引
    #创建索引:alter tabler + 表名 add index  idx_+索引名
    
    mysql> alter table student2 add  index idx_sage_sage(sage);
    Query OK, 0 rows affected (0.14 sec)
    Records: 0  Duplicates: 0  Warnings: 0
    
    mysql> desc student2;
    +----------+---------------------+------+-----+-------------------+----------------+
    | Field    | Type                | Null | Key | Default           | Extra          |
    +----------+---------------------+------+-----+-------------------+----------------+
    | sid      | int(11)             | NO   | PRI | NULL              | auto_increment |
    | sname    | varchar(10)         | NO   | MUL | NULL              |                |
    | sage     | tinyint(3) unsigned | YES  | MUL | NULL              |                |
    | sgender  | enum('m','f')       | NO   |     | m                 |                |
    | cometime | datetime            | NO   |     | CURRENT_TIMESTAMP |                |
    +----------+---------------------+------+-----+-------------------+----------------+
    5 rows in set (0.00 sec)
    
    mysql> show create table student2;
    +----------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
    | Table    | Create Table                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
    +----------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
    | student2 | CREATE TABLE `student2` (
      `sid` int(11) NOT NULL AUTO_INCREMENT COMMENT '学号',
      `sname` varchar(10) NOT NULL COMMENT '学生姓名',
      `sage` tinyint(3) unsigned DEFAULT NULL COMMENT '学生年龄',
      `sgender` enum('m','f') NOT NULL DEFAULT 'm' COMMENT '学生性别',
      `cometime` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '入学时间',
      PRIMARY KEY (`sid`),
      KEY `idx_snamex_sname` (`sname`),
      KEY `idx_sage_sage` (`sage`)
    ) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8                   |
    +----------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
    1 row in set (0.00 sec)
    
    
    2.主键索引
    #alter table +表名 add primary key pri_+想加的主索引名字
    
    mysql> alter table st add primary key pri_id(id);
    Query OK, 3 rows affected (0.09 sec)
    Records: 3  Duplicates: 0  Warnings: 0
    
    mysql> desc st;
    +-------+-------------+------+-----+---------+-------+
    | Field | Type        | Null | Key | Default | Extra |
    +-------+-------------+------+-----+---------+-------+
    | id    | int(11)     | NO   | PRI | 0       |       |
    | name  | varchar(10) | YES  |     | NULL    |       |
    +-------+-------------+------+-----+---------+-------+
    2 rows in set (0.00 sec)
    
    
    
    
    3.唯一键
    #判断唯一键是否唯一  要去重
    mysql> select count(distinct(name)) from st;
    +-----------------------+
    | count(distinct(name)) |
    +-----------------------+
    |                     3 |
    +-----------------------+
    1 row in set (0.18 sec)
    
    
    
    #创建索引
    
    
    alter table + 表名 add unique key uni_+想创唯一索引的名字
    mysql> alter table st add unique key uni_name(name);
    Query OK, 0 rows affected (0.06 sec)
    Records: 0  Duplicates: 0  Warnings: 0
    
    mysql> desc st;
    +-------+-------------+------+-----+---------+-------+
    | Field | Type        | Null | Key | Default | Extra |
    +-------+-------------+------+-----+---------+-------+
    | id    | int(11)     | NO   | PRI | 0       |       |
    | name  | varchar(10) | YES  | UNI | NULL    |       |
    +-------+-------------+------+-----+---------+-------+
    2 rows in set (0.00 sec)
    
    
    
    4.查看索引
    mysql> desc st;
    mysql> show index from st;
    
    mysql> show create table +表名
    
    +-------+-------------+------+-----+---------+-------+
    | Field | Type        | Null | Key | Default | Extra |
    +-------+-------------+------+-----+---------+-------+
    | id    | int(11)     | NO   | PRI | 0       |       |
    | name  | varchar(10) | YES  | UNI | NULL    |       |
    +-------+-------------+------+-----+---------+-------+
    
    
    5.创前缀索引
    mysql> alter table student2 add index idx_sname2(sname(3));
    Query OK, 0 rows affected (0.12 sec)
    Records: 0  Duplicates: 0  Warnings: 0
    
    
    
    
    6.删除索引
    mysql> alter table student2 drop index idx_sname;
    
    
    
     create table xiangqin(
        name varchar(10),
       age int,
        monet bigint,
        body varchar(10),
         hight int,
        weigh int,
        face varchar(10),
         sex enum('f','m'));
    
    
    

    #删除索引
    
    mysql> alter table +表名 drop index idx_+想删除的列
    | student2 | CREATE TABLE `student2` (
      `sid` int(11) NOT NULL AUTO_INCREMENT COMMENT '学号',
      `sname` varchar(10) NOT NULL COMMENT '学生姓名',
      `sage` tinyint(3) unsigned DEFAULT NULL COMMENT '学生年龄',
      `sgender` enum('m','f') NOT NULL DEFAULT 'm' COMMENT '学生性别',
      `cometime` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP COMMENT '入学时间',
      PRIMARY KEY (`sid`),
      KEY `idx_snamex_sname` (`sname`),
      KEY `idx_sname2` (`sname`(3)),
      KEY `idx_sgender` (`sgender`)
    ) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8                   |
    
    1 row in set (0.00 sec)
    
    mysql> alter table student2 drop index idx_snamex_sname;
    Query OK, 0 rows affected (0.00 sec)
    Records: 0  Duplicates: 0  Warnings: 0
    
    
    

    5.前缀索引和联合索引

    1.前缀索引
    1.在创建索引的时候,会把改列所有的数据按照btree的方式进行排序
    2.创建索引,会占用磁盘空间
    3.在同一列上,尽量避免创多个索引
    4.在大列上创建,前缀索引
    如果有,就使用前缀索引
    
    

    根据字段的前N个字符建立索引

    alter table test add index idx_name(name(10));
    
    
    2.联合索引
    给多个字段,创建一个索引
    例:
    where a.女生 and b.身高 and c.体重 and d.身材好
     index(a,b,c)
    特点:前缀生效特性
     a,ab,ac,abc,abcd 可以走索引或部分走索引
    b bc bcd cd c d ba ... 不走索引
    
    
    创建联合索引:
     mysql> alter table xiangqin add index idx_all(age,monet,body,hight,face);
    查看:
    mysql> show create  table xiangqin;
    
    
    

    原则:把最常用来做为条件查询的列放在最前面

    #创建people表
    create table people (id int,name varchar(20),age tinyint,money int ,gender enum('m','f'));
    #创建联合索引
    alter table people add index  idx_gam(gender,age,money);
    
    
    6.总结
    创建索引
    alter tabler + 表名 add index  idx_+索引名
    #创建主键索引
    #alter table +表名 add primary key pri_+想加的主索引名字
    #创建唯一索引
    alter table + 表名 add unique key uni_+想创唯一索引的名字
    #查看索引
    mysql> desc st;   主键是prl 唯一键是mul 普通键是uni
    mysql> show index from st;
    mysql> show create table +表名
    然后主键和唯一键 都是0 普通键是1
    
    
    #查询 走索引
    mysql> select * from xiangqin where sex='f' and money>10000000 and body='perfact' and face='nice'; 不走索引 mysql> select * from xiangqin where money>10000000 and body='perfact' and face='nice'; mysql> select * from xiangqin where money>10000000 and body='perfact' and face='nice' and sex='f'; alter table xiangqin add index idx_all(a,b,c,d); select * from xiangqin where a b c d a b c a b a c(部分走索引) a b d abdc bcd cdbd
    创建索引:
    1.不要在所有字段上都创建索引
    2.如果有需求字段比较多,选择联合索引
    3.如果有需求字段数据比较大,选择前缀索引
    4.如果可以创建唯一索引,一定创建唯一索引
    
    

    二.explain详解

    7.explain命令使用方法

    mysql> explain select * from city where countrycode='USA' or counttrycode='CHN';
    +----+-------------+-------+-------+---------------+-------------+---------+------+------+-----------------------+
    | id | select_type | table | type  | possible_keys | key         | key_len | ref  | rows | Extra                 |
    +----+-------------+-------+-------+---------------+-------------+---------+------+------+-----------------------+
    |  1 | SIMPLE      | city  | range | CountryCode   | CountryCode | 3       | NULL |  637 | Using index condition |
    +----+-------------+-------+-------+---------------+-------------+---------+------+------+-----------------------+
    1 row in set (0.00 sec)
    
    
    

    全表扫描

    mysql> explain select * from city;
    +----+-------------+-------+------+---------------+------+---------+------+------+-------+
    | id | select_type | table | type | possible_keys | key  | key_len | ref  | rows | Extra |
    +----+-------------+-------+------+---------------+------+---------+------+------+-------+
    |  1 | SIMPLE      | city  | ALL  | NULL          | NULL | NULL    | NULL | 4188 | NULL  |
    +----+-------------+-------+------+---------------+------+---------+------+------+-------+
    1 row in set (0.00 sec)
    
    
    
    
    
    mysql> explain select * from city where District='zhejiang';
    +----+-------------+-------+------+---------------+------+---------+------+------+-------------+
    | id | select_type | table | type | possible_keys | key  | key_len | ref  | rows | Extra       |
    +----+-------------+-------+------+---------------+------+---------+------+------+-------------+
    |  1 | SIMPLE      | city  | ALL  | NULL          | NULL | NULL    | NULL | 4188 | Using where |
    +----+-------------+-------+------+---------------+------+---------+------+------+-------------+
    
    
    

    生产中,mysql在使用全表扫描时的性能是极其差的,所以MySQL尽量避免出现全表扫描

    mysql> explain select name,countrycode from city where id=1;
    
    
    1.explain命令应用

    查询数据的方式

    1.全表扫描1)在explain语句结果中type为ALL
    
    2)什么时候出现全表扫描?
    
    
    
       2.1 业务确实要获取所有数据
       2.2 不走索引导致的全表扫描
       2.2.1 没索引
       2.2.2 索引创建有问题
       2.2.3 语句有问题
    
    
    实例
    mysql> explain select * from city where countrycode='USA' or countrycode='CHN';
    
    mysql>  explain select * from city where countrycode='USA' union all select * from city where countrycode='CHN';
    
    
    

    • 2.索引扫描

    2.1 常见的索引扫描类型:

    1)index 全索引扫描

    mysql> explain select sid from student2;
    +----+-------------+----------+-------+---------------+-------------+---------+------+------+-------------+
    | id | select_type | table    | type  | possible_keys | key         | key_len | ref  | rows | Extra       |
    +----+-------------+----------+-------+---------------+-------------+---------+------+------+-------------+
    |  1 | SIMPLE      | student2 | index | NULL          | idx_sgender | 1       | NULL |    2 | Using index |
    +----+-------------+----------+-------+---------------+-------------+---------+------+------+-------------+
    1 row in set (0.00 sec)
    
    
    mysql> explain select population from city;
    
    

    2)range

    mysql> explain select * from student2 where sid>1;
    +----+-------------+----------+-------+---------------+---------+---------+------+------+-------------+
    | id | select_type | table    | type  | possible_keys | key     | key_len | ref  | rows | Extra       |
    +----+-------------+----------+-------+---------------+---------+---------+------+------+-------------+
    |  1 | SIMPLE      | student2 | range | PRIMARY       | PRIMARY | 4       | NULL |    1 | Using where |
    +----+-------------+----------+-------+---------------+---------+---------+------+------+-------------+
    1 row in set (0.00 sec)
    
    
    

    3)ref 精确查找

     explain select * from city where countrycode='USA' union all select * from city where countrycode='CHN';
    
    
    

    4)eq_ref 主键索引,唯一索引

     explain select score.mark,student.sname from score join student on score.sno=student.sno;
    
    
    
    1. const system
    mysql> explain select * from student2 where sid=1;
    
    
    1. null
    mysql> explain select * from student2 where sid=1000000000000000000000000;
    
    

    一般我们说,只要一条SQL语句,达到range级别,那我们认为,该SQL语句的效率是OK的

    从上到下,性能从最差到最好,我们认为至少要达到range级别

    index:Full Index Scan,index与ALL区别为index类型只遍历索引树。
    range:索引范围扫描,对索引的扫描开始于某一点,返回匹配值域的行。显而易见的索引范围扫描是带有between或者where子句里带有<,>查询。
    
    
    mysql> alter table city add index idx_city(population);
    mysql> explain select * from city where population>30000000;
    
    

    Extra(扩展)
    Using temporary
    Using filesort 使用了默认的文件排序(如果使用了索引,会避免这类排序)
    Using join buffer

    mysql> mysql> explain select * from city where countrycode='CHN' order by population;
    +----+-------------+-------+------+---------------+-------------+---------+-------+------+----------------------------------------------------+
    | id | select_type | table | type | possible_keys | key         | key_len | ref   | rows | Extra                                              |
    +----+-------------+-------+------+---------------+-------------+---------+-------+------+----------------------------------------------------+
    |  1 | SIMPLE      | city  | ref  | CountryCode   | CountryCode | 3       | const |  363 | Using index condition; Using where; Using filesort |
    +----+-------------+-------+------+---------------+-------------+---------+-------+------+----------------------------------------------------+
    
    
    mysql> explain select * from city where population=30000 order by population;
    
    

    key_len: 越小越好

    • 前缀索引去控制

    rows: 越小越好

    建立索引的规范

    1.尽量使用唯一索引

    唯一性索引的值是唯一的,可以更快速的通过该索引来确定某条记录。
    
    注意:如果重复值较多,可以考虑采用联合索引
    
    
    
    

    2.为经常需要排序、分组和联合操作的字段建立索引

    例如:
    经常需要ORDER BY、GROUP BY、DISTINCT和UNION等操作的字段,排序操作会浪费很多时间。
    如果为其建立索引,可以有效地避免排序操作
    
    

    3.为常作为查询条件的字段建立索引

    如果某个字段经常用来做查询条件,那么该字段的查询速度会影响整个表的查询速度。
    
    因此,为这样的字段建立索引,可以提高整个表的查询速度。
    
    
    • 3.1 经常查询
    • 3.2 列值的重复值少

    注:如果经常作为条件的列,重复值特别多,可以建立联合索引

    4.尽量使用前缀来索引

    如果索引字段的值很长,最好使用值的前缀来索引。例如,TEXT和BLOG类型的字段,进行全文检索
    会很浪费时间。如果只检索字段的前面的若干个字符,这样可以提高检索速度。
    
    

    5.限制索引的数目

    索引的数目不是越多越好。每个索引都需要占用磁盘空间,索引越多,需要的磁盘空
    
    

    6.删除不再使用或者很少使用的索引

    表中的数据被大量更新,或者数据的使用方式被改变后,原有的一些索引可能不再需要。数据库管理
    员应当定期找出这些索引,将它们删除,从而减少索引对更新操作的影响。
    
    

    创建索引,什么时候不走索引

    1.没有查询条件的时候,不走索引

    #全表扫描
    select * from table;
    select  * from tab where 1=1;
    
    

    在业务数据库中,特别是数据量比较大的表,是没有全表扫描这种需求。

    1)对用户查看是非常痛苦的。
    2)对服务器来讲毁灭性的。
    3)SQL改写成以下语句:
    
    
    select * from table limit 10;
    
    

    2.查询结果集是原表中的大部分数据,应该是25%以上

    mysql> explain select * from city where population>3000;
    +----+-------------+-------+------+---------------+------+---------+------+------+-------------+
    | id | select_type | table | type | possible_keys | key  | key_len | ref  | rows | Extra       |
    +----+-------------+-------+------+---------------+------+---------+------+------+-------------+
    |  1 | SIMPLE      | city  | ALL  | idx_pop       | NULL | NULL    | NULL | 4188 | Using where |
    +----+-------------+-------+------+---------------+------+---------+------+------+-------------+
    1 row in set (0.00 sec)
    
    mysql> explain select * from city where population>3000 limit 10;
    +----+-------------+-------+-------+---------------+---------+---------+------+------+-----------------------+
    | id | select_type | table | type  | possible_keys | key     | key_len | ref  | rows | Extra                 |
    +----+-------------+-------+-------+---------------+---------+---------+------+------+-----------------------+
    |  1 | SIMPLE      | city  | range | idx_pop       | idx_pop | 4       | NULL | 4053 | Using index condition |
    +----+-------------+-------+-------+---------------+---------+---------+------+------+-----------------------+
    
    

    1)如果业务允许,可以使用limit控制。
    2)结合业务判断,有没有更好的方式。如果没有更好的改写方案就尽量不要在mysql存放这个数据了,放到redis里面。

    3.索引损坏,不走索引

    索引有自我维护的能力。
    对于表内容变化比较频繁的情况下,有可能会出现索引失效。
    重建索引就可以解决

    4.查询条件使用函数在索引列上或者对索引列进行运算,运算包括(+,-,*等)

    mysql> explain select * from student2 where sid-1=8;
    
    #例子
    错误的例子:select * from test where id-1=9; 
    正确的例子:select * from test where id=10;
    
    

    全表扫描

    5.隐式转换导致索引失效.这一点应当引起重视.也是开发中经常会犯的错误

    mysql> create table test(id int,name varchar(10),phone varchar(11))
    
    
    mysql> explain select * from test where phone=133;
    +----+-------------+-------+------+---------------+------+---------+------+------+-------------+
    | id | select_type | table | type | possible_keys | key  | key_len | ref  | rows | Extra       |
    +----+-------------+-------+------+---------------+------+---------+------+------+-------------+
    |  1 | SIMPLE      | test  | ALL  | uni_phone     | NULL | NULL    | NULL |    2 | Using where |
    +----+-------------+-------+------+---------------+------+---------+------+------+-------------+
    1 row in set (0.00 sec)
    
    mysql> explain select * from test where phone='133';
    +----+-------------+-------+-------+---------------+-----------+---------+-------+------+-------+
    | id | select_type | table | type  | possible_keys | key       | key_len | ref   | rows | Extra |
    +----+-------------+-------+-------+---------------+-----------+---------+-------+------+-------+
    |  1 | SIMPLE      | test  | const | uni_phone     | uni_phone | 36      | const |    1 | NULL  |
    +----+-------------+-------+-------+---------------+-----------+---------+-------+------+-------+
    
    

    6. <> ,not in 不走索引

    mysql> explain select * from test where phone not in ('133','120');
    mysql> explain select * from test where phone <> '133';
    
    

    单独的>,<,in 有可能走,也有可能不走,和结果集有关,尽量结合业务添加limit
    or或in尽量改成union

    推荐使用union all 联合查询

    mysql> explain select * from test where phone > '133' union all select * from test where phone < '133';
    
    

    7.like "%_" 百分号在最前面不走

    mysql> explain select * from test where phone like '13%';                                                                             
    +----+-------------+-------+-------+---------------+-----------+---------+------+------+-----------------------+
    | id | select_type | table | type  | possible_keys | key       | key_len | ref  | rows | Extra                 |
    +----+-------------+-------+-------+---------------+-----------+---------+------+------+-----------------------+
    |  1 | SIMPLE      | test  | range | uni_phone     | uni_phone | 36      | NULL |    1 | Using index condition |
    +----+-------------+-------+-------+---------------+-----------+---------+------+------+-----------------------+
    1 row in set (0.00 sec)
    
    mysql> explain select * from test where phone like '%13';
    +----+-------------+-------+------+---------------+------+---------+------+------+-------------+
    | id | select_type | table | type | possible_keys | key  | key_len | ref  | rows | Extra       |
    +----+-------------+-------+------+---------------+------+---------+------+------+-------------+
    |  1 | SIMPLE      | test  | ALL  | NULL          | NULL | NULL    | NULL |    2 | Using where |
    +----+-------------+-------+------+---------------+------+---------+------+------+-------------+
    
    

    企业中,需求使用like模糊查询。

    推荐不使用MySQL,使用elasticsearch   search engine
    
    

    8.单独引用联合索引里非第一位置的索引列

    如果一个SQL语句,是慢查询:

    1.有没有创建索引
    
    2.查看数据类型,和查询语句是否一致
    
    3.查询语句中,是否使用字段做运算
    
    4.查询出来的结果集很大,limit
    
    5.查询语句中是否使用<> 或者 not in
    
    6.查询语句中是否使用模糊查询,且%在前面
    
    7.如果使用联合索引,请按照创建索引的顺序查询
    
    8.索引损坏
    
    

    MySQL存储引擎

    1、MySQL引擎:
    
    1.1 可以理解为,MySQL的“文件系统”,只不过功能更加强大。
    
    
    
    2、MySQL引擎功能:
    
    2.1 除了可以提供基本的存取功能,还有更多功能事务功能、锁定、备份和恢复、优化以及特殊功能
    
    
    
    

    MySQL存储引擎:

    01)InnoDB0

    02)MyISAM

    #查看存储引擎
    mysql> show engines;
    #查看数据库中哪些表是myisam
    mysql> select table_schema,table_name,engine from information_schema.tables where engine='myisam';
    
    #查看数据库中哪些表是innodb
    mysql> select table_schema,table_name,engine from information_schema.tables where engine='innodb';
    
    

    innodb 和 myisam物理区别

    # myisam
    -rw-rw---- 1 mysql mysql  10684 Nov  1 10:53 user.frm
    -rw-rw---- 1 mysql mysql   1360 Nov  4 17:04 user.MYD
    -rw-rw---- 1 mysql mysql   2048 Nov  4 17:04 user.MYI
    
    # innodb
    -rw-rw---- 1 mysql mysql   8586 Nov  5 11:44 score.frm
    -rw-rw---- 1 mysql mysql  98304 Nov  5 11:45 score.ibd
    
    

    innodb核心特性

    MVCC
    事务
    行级锁
    热备份
    Crash Safe Recovery(自动故障恢复)

    # 查看当前的存储引擎
    mysql> SELECT @@default_storage_engine;
    +--------------------------+
    | @@default_storage_engine |
    +--------------------------+
    | InnoDB                   |
    +--------------------------+
    
    # 查看表的存储引擎
    mysql> show create table world.city;
    
    #设置默认存储引擎
    [mysqld]
    default-storage-engine=innodb
    
    mysql> SET @@storage_engine=myisam;
    Query OK, 0 rows affected, 1 warning (0.00 sec)
    
    mysql> select @@default_storage_engine;
    
    #建表的时候指定存储引擎
    CREATE TABLE t (i INT) ENGINE = <Storage Engine>;
    
    
  • 相关阅读:
    node md5
    Iptables入门教程
    centos 6.5 yum安装lnmp
    SSH日志位置
    【收藏】实战Nginx与PHP(FastCGI)的安装、配置与优化
    读《微博春晚背后的技术故事》笔记
    下载整个网页的方法,包括样式、图片、和js
    【收藏】下载Chrome商店插件的方法,万恶的gwd
    nginx变量
    【收藏】SSH原理与运用
  • 原文地址:https://www.cnblogs.com/223zhp/p/11905983.html
Copyright © 2020-2023  润新知