durpal 8的目录结构：

.
├── docker-compose.yml
├── dump
│   └── drupal.sql
├── sessions
└── www
    └── core
    └── site
    └── modules
    └── vendor
    └── index.php

my settings.php数据库配置

$databases['default']['default'] = array (
'database' => 'drupal',
'username' => 'root',
'password' => 'test',
'prefix' => '',
'host' => '127.0.0.1',
'port' => '3306',
'namespace' => 'Drupal\\Core\\Database\\Driver\\mysql',
'driver' => 'mysql',
);

我的docker-compose.yml代码

version: "2"
services:
www:
    image: drupal:8
    ports: 
        - "8001:80"
    volumes:
        - ./www:/var/www/html/
    depends_on:
        - db
    networks:
        - default
db:
    image: mysql:latest
    command: --default-authentication-plugin=mysql_native_password
    ports: 
        - "3306:3306"
    environment:
        MYSQL_DATABASE: drupal
        MYSQL_USER: user
        MYSQL_PASSWORD: test
        MYSQL_ROOT_PASSWORD: test
    volumes:
        - ./dump:/docker-entrypoint-initdb.d
        - /var/lib/mysql
    networks:
        - default
phpmyadmin:
    image: phpmyadmin/phpmyadmin
    links: 
        - db:db
    ports:
        - 8000:80
    environment:
        PMA_HOST: db
        MYSQL_USER: user
        MYSQL_PASSWORD: test
        MYSQL_ROOT_PASSWORD: test

使用上面的代码，我可以将phpmyadmin连接到mysql，并且工作正常，但我无法将drupal连接到mysql，出现以下错误：
pdoexception:sqlstate[hy000][2002]第79行的/var/www/html/core/lib/drupal/component/dependencyinjection/phparraycontainer.php中的连接被拒绝#0/var/www/html/core/lib/drupal/core/database/driver/mysql/connection.php（420）：pdo->mysql:host=127....'根'，'测试'，数组）\n#1/var/www/html/core/lib/drupal/core/database/database.php（371）：drupal\core\database\driver\mysql\connection:：open（数组）\n#2/var/www/html/core/lib/drupal/core/database/database.php（166）：drupal\core\database\database:：openconnection（'default'，'default'）\n#3[内部函数]：drupal\core\database\database:：getconnection（'default'）\n#4/var/www/html/core/lib/drupal/component/dependencyinjection/phparraycontainer.php（79）：调用\u user\u func\u array（'drupal\core\dat…'，array）\n#5/var/www/html/core/lib/drupal/component/dependencyinjection/container.php（171）：drupal\component\dependencyinjection\phparraycontainer->createservice（array，'database'）\n#6/var/www/html/core/lib/drupal/component/dependencyinjection/phparraycontainer.php（260）：drupal\component\dependencyinjection\container->get（'database'，1）\n#7/var/www/html/core/lib/drupal/component/dependencyinjection/phparraycontainer.php（62）：drupal\component\dependencyinjection\phparraycontainer->resolveservicesandparameters（array）\n#8/var/www/html/core/lib/drupal/component/dependencyinjection/container.php（171）：drupal\component\dependencyinjection\phparraycontainer->createservice（array，'cache.container'）\n#9/var/www/html/core/lib/drupal/core/drupalkernel.php（515）：drupal\component\dependencyinjection\container->get（'cache.container'）\n#10/var/www/html/core/lib/drupal/core/drupalkernel.php（876）：drupal\core\drupalkernel->getcachedcontainerdefinition（）\n#11/var/www/html/core/lib/drupal/core/drupalkernel.php（468）：drupal\core\drupalkernel->initializecontainer（）\n#12/var/www/html/core/lib/drupal/core/drupalkernel.php（664）：drupal\core\drupalkernel->boot（）\n#13/var/www/html/index.php（19）：drupal\core\drupalkernel->handle（object（symfony\component\httpfoundation\request））\n#14{main}