laravel怎么连接两个数据库查询数据

'connections' => [    'mysql' => [        //mysql主数据库        'driver' => 'mysql',        'host' => 'localhost',        'database' => 'db1',        'username' => 'root',        'password' => '',    ],    'mysql2' => [        //mysql2次数据库        'driver' => 'mysql',        'host' => 'localhost',        'database' => 'db2',        'username' => 'root',        'password' => '',    ],],

<?phpnamespace AppModels;use IlluminateDatabaseEloquentModel;class ModelBase extends Model{    // mysql    protected $connection = 'mysql';    // mysql2    protected $connection2 = 'mysql2';    protected function getConnectionName()    {        if ($this->getConnection() === $this->connection2) {            return $this->connection2;        }        return $this->connection;    }    public function getTable()    {        $table = parent::getTable();        if ($this->getConnection() === $this->connection2) {            $table = 'db2.' . $table;        }        return $table;    }}

namespace AppModels;class UserModel extends ModelBase{    protected $table = 'user';}