连接MySQL报错，is not allowed to connect to this MySQL server

问题描述：

    本机装的MySQL数据库，本机可以正常连接，其他机器访问报错，is not allowed to connect to this MySQL server，防火墙等其他策略均配置没问题

。

![](https://img-blog.csdnimg.cn/3aa85a50b6114a4fbab5e4b7cfc43c25.png)

解决方案：

    出现该问题的原因是，MySQL数据库只允许自身所在的本机器连接，不允许远程连接。

1、在MySQL所在服务器上使用命令登录到MySQL数据库中

mysql -u root -p

2、选择mysql数据库，并查询权限

use mysql;
 
select host from user where user='root';

可以看到，执行查询语句后得到的数据结果中 host 的值是 localhost

我们执行update语句修改权限

update user set host = '%' where user ='root';

3、刷新配置

flush privileges;

再次执行查询权限语句

select host from user where user='root';

可以看到，已经修改成功

4、最后再次用其他机器连接MySQL数据库，可以连接成功

DBMS: MySQL (版本 5.7.41)
区分大小写: 普通形式=lower, 分隔形式=lower
驱动程序: MySQL Connector/J (版本 mysql-connector-java-8.0.25 (Revision: 08be9e9b4cba6aa115f9b27b215887af40b159e0)，JDBC4.2)

Ping: 29毫秒
SSL: yes

<?xml version="1.0" encoding="UTF-8"?>
 
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<!--
 | This is the configuration file for Maven. It can be specified at two levels:
 |
 |  1. User Level. This settings.xml file provides configuration for a single user,
 |                 and is normally provided in ${user.home}/.m2/settings.xml.
 |
 |                 NOTE: This location can be overridden with the CLI option:
 |
 |                 -s /path/to/user/settings.xml
 |
 |  2. Global Level. This settings.xml file provides configuration for all Maven
 |                 users on a machine (assuming they're all using the same Maven
 |                 installation). It's normally provided in
 |                 ${maven.conf}/settings.xml.
 |
 |                 NOTE: This location can be overridden with the CLI option:
 |
 |                 -gs /path/to/global/settings.xml
 |
 | The sections in this sample file are intended to give you a running start at
 | getting the most out of your Maven installation. Where appropriate, the default
 | values (values used when the setting is not specified) are provided.
 |
 |-->
<settings xmlns="http://maven.apache.org/SETTINGS/1.2.0"
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.2.0 https://maven.apache.org/xsd/settings-1.2.0.xsd">
  <!-- localRepository
   | The path to the local repository maven will use to store artifacts.
   |
   | Default: ${user.home}/.m2/repository
  <localRepository>/path/to/local/repo</localRepository>
  -->
 
  <!-- interactiveMode
   | This will determine whether maven prompts you when it needs input. If set to false,
   | maven will use a sensible default value, perhaps based on some other setting, for
   | the parameter in question.
   |
   | Default: true
  <interactiveMode>true</interactiveMode>
  -->
 
  <!-- offline
   | Determines whether maven should attempt to connect to the network when executing a build.
   | This will have an effect on artifact downloads, artifact deployment, and others.
   |
   | Default: false
  <offline>false</offline>
  -->
 
  <!-- pluginGroups
   | This is a list of additional group identifiers that will be searched when resolving plugins by their prefix, i.e.
   | when invoking a command line like "mvn prefix:goal". Maven will automatically add the group identifiers
   | "org.apache.maven.plugins" and "org.codehaus.mojo" if these are not already contained in the list.
   |-->
  <pluginGroups>
    <!-- pluginGroup
     | Specifies a further group identifier to use for plugin lookup.
    <pluginGroup>com.your.plugins</pluginGroup>
    -->
  </pluginGroups>
 
  <!-- proxies
   | This is a list of proxies which can be used on this machine to connect to the network.
   | Unless otherwise specified (by system property or command-line switch), the first proxy
   | specification in this list marked as active will be used.
   |-->
  <proxies>
    <!-- proxy
     | Specification for one proxy, to be used in connecting to the network.
     |
    <proxy>
      <id>optional</id>
      <active>true</active>
      <protocol>http</protocol>
      <username>proxyuser</username>
      <password>proxypass</password>
      <host>proxy.host.net</host>
      <port>80</port>
      <nonProxyHosts>local.net|some.host.com</nonProxyHosts>
    </proxy>
    -->
  </proxies>
 
  <!-- servers
   | This is a list of authentication profiles, keyed by the server-id used within the system.
   | Authentication profiles can be used whenever maven must make a connection to a remote server.
   |-->
  <servers>
    <!-- server
     | Specifies the authentication information to use when connecting to a particular server, identified by
     | a unique name within the system (referred to by the 'id' attribute below).
     |
     | NOTE: You should either specify username/password OR privateKey/passphrase, since these pairings are
     |       used together.
     |
    <server>
      <id>deploymentRepo</id>
      <username>repouser</username>
      <password>repopwd</password>
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    <!-- Another sample, using keys to authenticate.
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  <!-- mirrors
   | This is a list of mirrors to be used in downloading artifacts from remote repositories.
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   | It works like this: a POM may declare a repository to use in resolving certain artifacts.
   | However, this repository may have problems with heavy traffic at times, so people have mirrored
   | it to several places.
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   | That repository definition will have a unique id, so we can create a mirror reference for that
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    <!-- mirror
     | Specifies a repository mirror site to use instead of a given repository. The repository that
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     |
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      <id>mirrorId</id>
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      <name>Human Readable Name for this Mirror.</name>
      <url>http://my.repository.com/repo/path</url>
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    <mirror>
      <id>maven-default-http-blocker</id>
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      <name>Pseudo repository to mirror external repositories initially using HTTP.</name>
      <url>http://0.0.0.0/</url>
      <blocked>true</blocked>
    </mirror>
  </mirrors>
 
  <!-- profiles
   | This is a list of profiles which can be activated in a variety of ways, and which can modify
   | the build process. Profiles provided in the settings.xml are intended to provide local machine-
   | specific paths and repository locations which allow the build to work in the local environment.
   |
   | For example, if you have an integration testing plugin - like cactus - that needs to know where
   | your Tomcat instance is installed, you can provide a variable here such that the variable is
   | dereferenced during the build process to configure the cactus plugin.
   |
   | As noted above, profiles can be activated in a variety of ways. One way - the activeProfiles
   | section of this document (settings.xml) - will be discussed later. Another way essentially
   | relies on the detection of a system property, either matching a particular value for the property,
   | or merely testing its existence. Profiles can also be activated by JDK version prefix, where a
   | value of '1.4' might activate a profile when the build is executed on a JDK version of '1.4.2_07'.
   | Finally, the list of active profiles can be specified directly from the command line.
   |
   | NOTE: For profiles defined in the settings.xml, you are restricted to specifying only artifact
   |       repositories, plugin repositories, and free-form properties to be used as configuration
   |       variables for plugins in the POM.
   |
   |-->
  <profiles>
    <!-- profile
     | Specifies a set of introductions to the build process, to be activated using one or more of the
     | mechanisms described above. For inheritance purposes, and to activate profiles via <activatedProfiles/>
     | or the command line, profiles have to have an ID that is unique.
     |
     | An encouraged best practice for profile identification is to use a consistent naming convention
     | for profiles, such as 'env-dev', 'env-test', 'env-production', 'user-jdcasey', 'user-brett', etc.
     | This will make it more intuitive to understand what the set of introduced profiles is attempting
     | to accomplish, particularly when you only have a list of profile id's for debug.
     |
     | This profile example uses the JDK version to trigger activation, and provides a JDK-specific repo.
    <profile>
      <id>jdk-1.4</id>
      <activation>
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          <layout>default</layout>
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    -->
 
    <!--
     | Here is another profile, activated by the system property 'target-env' with a value of 'dev',
     | which provides a specific path to the Tomcat instance. To use this, your plugin configuration
     | might hypothetically look like:
     |
     | ...
     | <plugin>
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     |   <artifactId>myplugin</artifactId>
     |
     |   <configuration>
     |     <tomcatLocation>${tomcatPath}</tomcatLocation>
     |   </configuration>
     | </plugin>
     | ...
     |
     | NOTE: If you just wanted to inject this configuration whenever someone set 'target-env' to
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     |
    <profile>
      <id>env-dev</id>
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  <!-- activeProfiles
   | List of profiles that are active for all builds.
   |
  <activeProfiles>
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  -->
</settings>

1。 改表法。可能是你的帐号不允许从远程登陆，只能在localhost。这个时候只要在localhost的那台电脑，登入mysql后，更改 "mysql" 数据库里的 "user" 表里的 "host" 项，从"localhost"改称"%"

Sql代码 复制代码

1. mysql -u root -pvmwaremysql>use mysql;

2. mysql>update user set host = '%' where user = 'root';

3. mysql>select host, user from user;

4. 授权法。例如，你想myuser使用mypassword从任何主机连接到mysql服务器的话。

Sql代码 复制代码

1. GRANT ALL PRIVILEGES ON . TO 'myuser'@'%' IDENTIFIED BY 'mypassword' WITH

   GRANT OPTION;

2.FLUSH PRIVILEGES;