本文教你如何实现Mycat与MySQL 8.x互连，也就是说实现Mycat连接MySQL 8.x数据库，同时，实现使用MySQL 8.x的命令行连接Mycat。
1.创建MySQL用户
首先，在MySQL8.x中创建Mycat连接MySQL的用户，如下所示。
CREATE USER 'mycat'@'192.168.175.%' IDENTIFIED BY 'mycat';
ALTER USER 'mycat'@'192.168.175.%' IDENTIFIED WITH mysql_native_password BY 'mycat';
GRANT SELECT, INSERT, UPDATE, DELETE ON *.* TO 'mycat'@'192.168.175.%';
FLUSH PRIVILEGES;2.配置schema.xml文件
<?xml version="1.0"?>
<!DOCTYPE mycat:schema SYSTEM "schema.dtd">
<mycat:schema xmlns:mycat="http://io.mycat/">
<schema name="shop" checkSQLschema="false" sqlMaxLimit="1000">
<table name="order_master" primaryKey="order_id" dataNode = "ordb"/>
<table name="order_detail" primaryKey="order_detail_id" dataNode = "ordb"/>
<table name="order_cart" primaryKey="cart_id" dataNode = "ordb"/>
<table name="order_customer_addr" primaryKey="customer_addr_id" dataNode = "ordb"/>
<table name="region_info" primaryKey="region_id" dataNode = "ordb"/>
<table name="serial" primaryKey="id" dataNode = "ordb"/>
<table name="shipping_info" primaryKey="ship_id" dataNode = "ordb"/>
<table name="warehouse_info" primaryKey="w_id" dataNode = "ordb"/>
<table name="warehouse_proudct" primaryKey="wp_id" dataNode = "ordb"/>
<table name="product_brand_info" primaryKey="brand_id" dataNode = "prodb"/>
<table name="product_category" primaryKey="category_id" dataNode = "prodb"/>
<table name="product_comment" primaryKey="comment_id" dataNode = "prodb"/>
<table name="product_info" primaryKey="product_id" dataNode = "prodb"/>
<table name="product_pic_info" primaryKey="product_pic_id" dataNode = "prodb"/>
<table name="product_supplier_info" primaryKey="supplier_id" dataNode = "prodb"/>
<table name="customer_balance_log" primaryKey="balance_id" dataNode = "custdb"/>
<table name="customer_inf" primaryKey="customer_inf_id" dataNode = "custdb"/>
<table name="customer_level_inf" primaryKey="customer_level" dataNode = "custdb"/>
<table name="customer_login" primaryKey="customer_id" dataNode = "custdb"/>
<table name="customer_login_log" primaryKey="login_id" dataNode = "custdb"/>
<table name="customer_point_log" primaryKey="point_id" dataNode = "custdb"/>
</schema>
<dataNode name="ordb" dataHost="binghe152" database="order_db" />
<dataNode name="prodb" dataHost="binghe153" database="product_db" />
<dataNode name="custdb" dataHost="binghe154" database="customer_db" />
<dataHost name="binghe152" maxCon="1000" minCon="10" balance="1"
writeType="0" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100">
<heartbeat>select user()</heartbeat>
<writeHost host="binghe52" url="192.168.175.152:3306" user="root" password="root"/>
</dataHost>
<dataHost name="binghe153" maxCon="1000" minCon="10" balance="1"
writeType="0" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100">
<heartbeat>select user()</heartbeat>
<writeHost host="binghe53" url="192.168.175.153:3306" user="root" password="root"/>
</dataHost>
<dataHost name="binghe154" maxCon="1000" minCon="10" balance="1"
writeType="0" dbType="mysql" dbDriver="native" switchType="1" slaveThreshold="100">
<heartbeat>select user()</heartbeat>
<writeHost host="binghe54" url="192.168.175.154:3306" user="root" password="root"/>
</dataHost>
</mycat:schema>3.配置server.xml文件
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mycat:server SYSTEM "server.dtd">
<mycat:server xmlns:mycat="http://io.mycat/">
<system>
<property name="useHandshakeV10">1</property>
<property name="defaultSqlParser">druidparser</property>
<property name="serverPort">3307</property>
<property name="managerPort">3308</property>
<property name="nonePasswordLogin">0</property>
<property name="bindIp">0.0.0.0</property>
<property name="charset">utf8mb4</property>
<property name="frontWriteQueueSize">2048</property>
<property name="txIsolation">2</property>
<property name="processors">2</property>
<property name="idleTimeout">1800000</property>
<property name="sqlExecuteTimeout">300</property>
<property name="useSqlStat">0</property>
<property name="useGlobleTableCheck">0</property>
<property name="sequenceHandlerType">2</property>
<property name="defaultMaxLimit">1000</property>
<property name="maxPacketSize">104857600</property>
</system>
<user name="mycat" defaultAccount="true">
<property name="usingDecrypt">1</property>
<property name="password">cTwf23RrpBCEmalp/nx0BAKenNhvNs2NSr9nYiMzHADeEDEfwVWlI6hBDccJjNBJqJxnunHFp5ae63PPnMfGYA==</property>
<property name="schemas">shop</property>
</user>
</mycat:server>注意：在需要使用MySQL 8.x的mysql命令连接Mycat时，在server.xml文件的system标签下必须配置如下选项。
<property name="useHandshakeV10">1</property>
<property name="defaultSqlParser">druidparser</property>否则，MySQL 8.x的mysql命令连接Mycat会失败。
user标签下的password标签的值为登录Mycat的密码，此值使用Mycat提供的加密类对密码明文进行了加密。此类存在于Mycat安装目录下的lib目录下的Mycat-server-xxx-release.jar中的io.mycat.util.DecryptUtil类，可以使用如下命令对密码进行加密。
java java -cp /usr/local/mycat/lib/Mycat-server-xxx-release.jar io.mycat.util.DecryptUtil 0:mycat:mycat其中0:mycat:mycat为运行Jar包的参数，0表示应用程序连接Mycat时使用密文密码；第一个mycat代表连接Mycat的用户名，也就是说为哪个用户的密码加密；第二个mycat代表需要加密的密码。
加密后的结果数据如下所示
cTwf23RrpBCEmalp/nx0BAKenNhvNs2NSr9nYiMzHADeEDEfwVWlI6hBDccJjNBJqJxnunHFp5ae63PPnMfGYA==即user标签下的password属性的值。
如果按照上述方式为连接Mycat的密码加密后，需要在user标签下配置如下选项，否则无法正确连接Mycat
<property name="usingDecrypt">1</property>4.连接Mycat
使用MySQL 8.x中的mysql命令连接Mycat，如下所示。
[root@binghe151 ~]# mysql -umycat -pmycat -h192.168.175.151 -P3307 --default-auth=mysql_native_password
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.6.29-mycat-xxx-release-20200228205020 MyCat Server (OpenCloudDB)
Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>使用MySQL8.x中的mysql命令连接Mycat时，需要注意的是要在mysql命令后面添加--default-auth=mysql_native_password选项。
接下来，查看下Mycat下的逻辑库和逻辑表，如下所示。
mysql> SHOW DATABASES;
+----------+
| DATABASE |
+----------+
| shop |
+----------+
1 row in set (0.00 sec)
mysql> USE shop;
Database changed
mysql> SHOW TABLES;
+-----------------------+
| Tables in shop |
+-----------------------+
| customer_balance_log |
| customer_inf |
| customer_level_inf |
| customer_login |
| customer_login_log |
| customer_point_log |
| order_cart |
| order_customer_addr |
| order_detail |
| order_master |
| product_brand_info |
| product_category |
| product_comment |
| product_info |
| product_pic_info |
| product_supplier_info |
| region_info |
| serial |
| shipping_info |
| warehouse_info |
| warehouse_proudct |
+-----------------------+
21 rows in set (0.00 sec)
mysql> SELECT product_id, product_code, product_name FROM product_info LIMIT 10;
+------------+------------------+---------------------------------------+
| product_id | product_code | product_name |
+------------+------------------+---------------------------------------+
| 1 | 3700000000000001 | [Columbia]打底裤示例商品-1 |
| 2 | 3600000000000001 | [TheNorthFace]小脚裤示例商品-1 |
| 3 | 3500000000000001 | [李宁]九分裤示例商品-1 |
| 4 | 3400000000000001 | [LOWA]哈伦裤示例商品-1 |
| 5 | 3300000000000001 | [JACK&JONES]连体裤示例商品-1 |
| 6 | 3200000000000001 | [诺诗兰]牛仔裤示例商品-1 |
| 7 | 3100000000000001 | [骆驼]休闲裤示例商品-1 |
| 8 | 3000000000000001 | [金狐狸]风衣示例商品-1 |
| 9 | 2900000000000001 | [Columbia]小西装示例商品-1 |
| 10 | 2800000000000001 | [李宁]外套示例商品-1 |
+------------+------------------+---------------------------------------+
10 rows in set (0.01 sec)至此，就配置完了，是不是很简单呢？喜欢的话点个赞吧！！
