§設定 JDBC 池

Play JDBC 資料來源由 HikariCP 管理。

§特殊網址

Play 支援 MySQL 和 PostgreSQL 的特殊網址格式

# To configure MySQL
db.default.url="mysql://user:password@localhost/database"

# To configure PostgreSQL
db.default.url="postgres://user:password@localhost/database"

可以指定資料庫服務的非標準埠

# To configure MySQL running in Docker
db.default.url="mysql://user:password@localhost:port/database"

# To configure PostgreSQL running in Docker
db.default.url="postgres://user:password@localhost:port/database"

§參考

除了傳統的 driver、url、username、password 設定屬性之外，在需要時，它還支援額外的調整參數。Play JDBC reference.conf 中的 play.db.prototype 設定用作所有資料庫連線設定的原型。所有可用設定選項的預設值可在此處查看

# Copyright (C) from 2022 The Play Framework Contributors <https://github.com/playframework>, 2011-2021 Lightbend Inc. <https://www.lightbend.com>

play {

  modules {
    enabled += "play.api.db.DBModule"
    enabled += "play.api.db.HikariCPModule"
  }

  # Database configuration
  db {
    # The name of the configuration item from which to read database config.
    # So, if set to db, means that db.default is where the configuration for the
    # database named default is found.
    config = "db"

    # The name of the default database, used when no database name is explicitly
    # specified.
    default = "default"

    # The default connection pool.
    # Valid values are:
    #  - default - Use the default connection pool provided by the platform (HikariCP)
    #  - hikaricp - Use HikariCP
    #  - A FQCN to a class that implements play.api.db.ConnectionPool
    pool = "default"

    # The prototype for database configuration
    prototype = {

      # The connection pool for this database.
      # Valid values are:
      #  - default - Delegate to play.db.pool
      #  - hikaricp - Use HikariCP
      #  - A FQCN to a class that implements play.api.db.ConnectionPool
      pool = "default"

      # The database driver
      driver = null

      # The database url
      url = null

      # The username
      username = null

      # The password
      password = null

      # If non null, binds the JNDI name to this data source to the given JNDI name.
      jndiName = null

      # If it should log sql statements
      logSql = false

      # HikariCP configuration options
      hikaricp {

        # The datasource class name, if not using a URL
        dataSourceClassName = null

        # Data source configuration options
        dataSource {
        }

        # Whether autocommit should be used
        autoCommit = true

        # The connection timeout
        connectionTimeout = 30 seconds

        # The idle timeout
        idleTimeout = 10 minutes

        # If non null, controls how frequently HikariCP will attempt to keep a connection alive
        keepaliveTime = null

        # The max lifetime of a connection
        maxLifetime = 30 minutes

        # If non null, the query that should be used to test connections
        connectionTestQuery = null

        # If non null, sets the minimum number of idle connections to maintain.
        minimumIdle = null

        # The maximum number of connections to make.
        maximumPoolSize = 10

        # If non null, sets the name of the connection pool.
        # Defaults to the database configuration item name.
        # Primarily used for stats reporting.
        poolName = null

        # This property controls whether the pool will "fail fast" if the pool cannot be seeded with
        # an initial connection successfully.
        # 1. Any positive number is taken to be the number of milliseconds to attempt to acquire an initial connection;
        #    the application thread will be blocked during this period. If a connection cannot be acquired before this
        #    timeout occurs, an exception will be thrown. This timeout is applied after the connectionTimeout period.
        # 2. If the value is zero (0), HikariCP will attempt to obtain and validate a connection. If a connection
        #    is obtained, but fails validation, an exception will be thrown and the pool not started. However, if
        #    a connection cannot be obtained, the pool will start, but later efforts to obtain a connection may fail.
        # 3. A value less than zero will bypass any initial connection attempt, and the pool will start immediately
        #    while trying to obtain connections in the background. Consequently, later efforts to obtain a connection
        #    may fail.
        initializationFailTimeout = -1

        # Sets whether internal queries should be isolated
        isolateInternalQueries = false

        # Sets whether pool suspension is allowed.  There is a performance impact to enabling it.
        allowPoolSuspension = false

        # Sets whether connections should be read only
        readOnly = false

        # Sets whether mbeans should be registered
        registerMbeans = false

        # If non null, sets the catalog that should be used on connections
        catalog = null

        # A SQL statement that will be executed after every new connection creation before adding it to the pool
        connectionInitSql = null

        # If non null, sets the transaction isolation level
        transactionIsolation = null

        # The user-supplied SQLExceptionOverride class name.
        exceptionOverrideClassName = null

        # The validation timeout to use
        validationTimeout = 5 seconds

        # If non null, sets the threshold for the amount of time that a connection has been out of the pool before it is
        # considered to have leaked
        leakDetectionThreshold = null
      }
    }
  }
}

當您需要為連線池指定一些設定時，您可以覆寫原型設定。例如，若要設定 HikariCP 的 maximumPoolSize，您會在 application.conf 檔案中設定下列內容

db.default.hikaricp.maximumPoolSize = 15

如果您需要為池中的連線指定一些驅動程式特定的屬性，您可以在 dataSource 設定中設定它們。例如，若要使用 HikariCP 設定 jdbc SQLServerDriver 的 queryTimeout，您會在 application.conf 檔案中設定下列內容

db.default.hikaricp.dataSource.queryTimeout = 15

下一步：設定 Play 的執行緒池

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