浅谈Slick(4)- Slick301:我的Slick开发项目设置

  前面几篇介绍里尝试了一些Slick的功能和使用方式,看来基本可以满足用scala语言进行数据库操作编程的要求,而且有些代码可以通过函数式编程模式来实现。我想,如果把Slick当作数据库操作编程主要方式的话,可能需要先制定一套比较规范的模式来应付日常开发(也要考虑团队开发)、测试和维护。首先从项目结构来说,我发现由Intellij-Idea IDE界面直接产生的SBT项目结构已经比较理想了。在src/main/resources是scala项目获取配置文件的默认目录、我们可以按照需要在src/main/scala下增加代码子目录(package)及在src/main/test下摆放测试代码。配置文件application.conf、logback.xml是放在src/main/resources下的。application.conf是Slick的配置文件,logback.xml是跟踪器logback(log4j)的配置文件。Slick把jdbc api集成到scala编程语言里,能够支持多种数据库。也就是说Slick提供了多种数据库的驱动api。Slick支持在配置文件application.conf里配置数据库功能模式,这样我们就可以在正式部署软件时才通过修订application.conf里的配置来决定具体的数据库种类和参数。当然前提是我们的程序代码不能依赖任何特别的数据库api。我们从表结构设定开始,先看看上篇Slick101里的例子:

 1 package com.datatech.learn.slick101
 2 import slick.driver.H2Driver.api._
 3 object slick101 {
 4 
 5 /* ----- schema  */
 6   //表字段对应模版
 7   case class AlbumModel (id: Long
 8                    ,title: String
 9                    ,year: Option[Int]
10                    ,artist: String
11                    )
12   //表结构: 定义字段类型, * 代表结果集字段
13   class AlbumTable(tag: Tag) extends Table[AlbumModel](tag, "ALBUMS") {
14     def id = column[Long]("ID",O.AutoInc,O.PrimaryKey)
15     def title = column[String]("TITLE")
16     def year = column[Option[Int]]("YEAR")
17     def artist = column[String]("ARTIST",O.Default("Unknown"))
18     def * = (id,title,year,artist) <> (AlbumModel.tupled, AlbumModel.unapply)
19   }
20   //库表实例
21   val albums = TableQuery[AlbumTable]

我们可以看到这段代码依赖了slick.driver.H2Driver.api,是专门针对H2 Database的了。我们可以用依赖注入(dependency injection, IOC)来解决这个依赖问题。先试试用最传统的依赖注入方式:传入参数来注入这个数据库驱动依赖,把代码放在src/main/scala/model/TableDefs.scala里:

 1 package com.bayakala.learn.slick301.model
 2 import slick.driver.JdbcProfile
 3 class TableDefs(val dbDriver: JdbcProfile) {
 4   import dbDriver.api._
 5   case class Supplier(id: Long
 6                       , name: String
 7                       , contact: Option[String]
 8                       , website: Option[String])
 9   final class Suppliers(tag: Tag) extends Table[Supplier](tag,"SUPPLERS") {
10     def id = column[Long]("ID",O.AutoInc,O.PrimaryKey)
11     def name = column[String]("NAME")
12     def contact = column[Option[String]]("CONTACT")
13     def website = column[Option[String]]("WEBSITE")
14     def * = (id, name, contact, website) <> (Supplier.tupled,Supplier.unapply)
15     def nidx = index("NM_IDX",name,unique = true)
16   }
17   val suppliers = TableQuery[Suppliers]
18 
19   case class Coffee(id: Long
20                      ,name: String
21                      ,supid: Long
22                      ,price: Double
23                      ,sales: Int)
24   final class Coffees(tag: Tag) extends Table[Coffee](tag, "COFFEES") {
25     def id = column[Long]("ID",O.AutoInc,O.PrimaryKey)
26     def name = column[String]("NAME")
27     def supid = column[Long]("SUPID")
28     def price = column[Double]("PRICE",O.Default(0.0))
29     def sales = column[Int]("SALES",O.Default(0))
30     def * = (id,name,supid,price,sales) <> (Coffee.tupled, Coffee.unapply)
31     def fk_sup = foreignKey("FK_SUP",supid,suppliers)(_.id,onDelete = ForeignKeyAction.Restrict,onUpdate = ForeignKeyAction.Cascade)
32     def supidx = index("SUP_IDX",supid,unique = false)
33     def nidx = index("NM_IDX",name,unique = true)
34   }
35   val coffees = TableQuery[Coffees]
36 
37 }

注意我们是把JdbcProfile作为参数注入了class TableDefs里。如果TableDefs经常需要作为其它类的父类继承的话,设计成trait能更加灵活的进行类型混合(type mixing)。这样的需求可以用cake pattern方式进行依赖注入。我们在需要src/main/scala/config/AppConfig.scala里定义依赖界面trait DBConfig:

1 package com.bayakala.learn.slick301.config
2 import slick.driver.JdbcProfile
3 trait DBConfig {
4   val jdbcDriver: JdbcProfile
5   import jdbcDriver.api._
6   val db: Database
7 }

后面我们可以通过实现多种DBConfig实例方式来构建开发、测试、部署等数据库环境。为了方便示范,我们设计几个基本的Query Action,放在src/main/scala/access/DAOs.scala里,用cake pattern注入依赖DBConfig:

 1 package com.bayakala.learn.slick301.access
 2 import com.bayakala.learn.slick301.config
 3 import com.bayakala.learn.slick301.config.DBConfig
 4 import com.bayakala.learn.slick301.model.TableDefs
 5 trait DAOs { dbconf: DBConfig =>
 6   import jdbcDriver.api._
 7   //注入依赖
 8   val tables = new TableDefs(dbconf.jdbcDriver)
 9   import tables._
10   //suppliers queries
11   val createSupplierTable = suppliers.schema.create
12   val allSuppliers = suppliers.result
13   def insertSupplier(id:Long,name:String,address:Option[String],website:Option[String])
14   = suppliers += Supplier(id,name,address,website)
15   def insertSupbyName(n: String) = suppliers.map(_.name) += n
16   //coffees queries
17   val createCoffeeTable = coffees.schema.create
18   val allCoffees = coffees.result
19   def insertCoffee(c: (Long,String,Long,Double,Int)) =
20     coffees += Coffee(id=c._1, name=c._2,supid=c._3,price=c._4,sales=c._5)
21 
22 }

dbconf: DBConfig => 的意思是在进行DAOs的实例化时必须混入(mixing)DBConfig类。

以上两个代码文件TableDefs.scala和DAOs.scala在注入依赖后都能够顺利通过编译了。

我们在src/main/scala/main/Main.scala里测试运算DAOs里的query action:

 1 package com.bayakala.learn.slick301.main
 2 import com.bayakala.learn.slick301.config.DBConfig
 3 import com.bayakala.learn.slick301.access.DAOs
 4 
 5 import scala.concurrent.{Await, Future}
 6 import scala.util.{Failure, Success}
 7 import scala.concurrent.duration._
 8 import scala.concurrent.ExecutionContext.Implicits.global
 9 import slick.backend.DatabaseConfig
10 import slick.driver.{H2Driver, JdbcProfile}
11 object Main {
12  
13   object Actions extends DAOs with DBConfig {
14     override lazy val jdbcDriver: JdbcProfile = H2Driver
15     val dbConf: DatabaseConfig[H2Driver] = DatabaseConfig.forConfig("h2")
16     override val db = dbConf.db
17   }
18   import Actions._
19   
20   def main(args: Array[String]) = {
21     val res = db.run(createSupplierTable).andThen {
22       case Success(_) => println("supplier table created")
23       case Failure(_) => println("unable to create supplier table")
24     }
25     Await.ready(res, 3 seconds)
26 
27     val res2 = db.run(insertSupbyName("Acme Coffee Co."))
28     Await.ready(res2, 3 seconds)
29 
30     Await.ready(db.run(allSuppliers), 10 seconds).foreach(println)
31 
32     val res10 = db.run(createCoffeeTable).andThen {
33       case Success(_) => println("coffee table created")
34       case Failure(_) => println("unable to create coffee table")
35     }
36     Await.ready(res10, 3 seconds)
37 
38     val res11 = db.run(insertCoffee((101,"Columbia",1,158.0,0)))
39     Await.ready(res11, 3 seconds)
40 
41     Await.ready(db.run(allCoffees), 10 seconds).foreach(println)
42 
43   }
44 
45 }

Actions是DAOs的实例。我们看到必须把DBConfig混入(mixin)。但是我们构建的数据库又变成了专门针对H2的api了,这样的话每次变动数据库对象我们就必须重新编译Main.scala,不符合上面我们提到的要求。我们可以把目标数据库放到application.conf里,然后在Main.scala里用typesafe-config实时根据application.conf里的设置确定数据库参数。src/main/resources/application.conf内容如下:

 1 app = {
 2   dbconfig = h2
 3 }
 4 
 5 h2 {
 6   driver = "slick.driver.H2Driver$"
 7   db {
 8     url = "jdbc:h2:~/slickdemo;mv_store=false"
 9     driver = "org.h2.Driver"
10     connectionPool = HikariCP
11     numThreads = 10
12     maxConnections = 12
13     minConnections = 4
14     keepAliveConnection = true
15   }
16 }
17 
18 h2mem = {
19   url = "jdbc:h2:mem:slickdemo"
20   driver = org.h2.Driver
21   connectionPool = disabled
22   keepAliveConnection = true
23 }
24 
25 mysql {
26   driver = "slick.driver.MySQLDriver$"
27   db {
28     url = "jdbc:mysql://localhost/slickdemo"
29     driver = com.mysql.jdbc.Driver
30     keepAliveConnection = true
31     user="root"
32     password="123"
33     numThreads=10
34     maxConnections = 12
35     minConnections = 4
36   }
37 }
38 
39 mysqldb = {
40   dataSourceClass = "com.mysql.jdbc.jdbc2.optional.MysqlDataSource"
41   properties {
42     user = "root"
43     password = "123"
44     databaseName = "slickdemo"
45     serverName = "localhost"
46   }
47   numThreads = 10
48   maxConnections = 12
49   minConnections = 4
50 }
51 
52 postgres {
53   driver = "slick.driver.PostgresDriver$"
54   db {
55     url = "jdbc:postgresql://127.0.0.1/slickdemo"
56     driver = "org.postgresql.Driver"
57     connectionPool = HikariCP
58     user = "slick"
59     password = "123"
60     numThreads = 10
61     maxConnections = 12
62     minConnections = 4
63   }
64 }
65 
66 postgressdb = {
67   dataSourceClass = "org.postgresql.ds.PGSimpleDataSource"
68   properties = {
69     databaseName = "slickdemo"
70     user = "slick"
71     password = "123"
72   }
73   connectionPool = HikariCP
74   numThreads = 10
75   maxConnections = 12
76   minConnections = 4
77 }
78 
79 mssql {
80   driver = "com.typesafe.slick.driver.ms.SQLServerDriver$"
81   db {
82     url = "jdbc:sqlserver://host:port"
83     driver = com.microsoft.sqlserver.jdbc.SQLServerDriver
84     connectionTimeout = 30 second
85     connectionPool = HikariCP
86     user = "slick"
87     password = "123"
88     numThreads = 10
89     maxConnections = 12
90     minConnections = 4
91     keepAliveConnection = true
92   }
93 }
94 
95 tsql {
96   driver = "slick.driver.H2Driver$"
97   db = ${h2mem}
98 }

现在application.conf里除了数据库配置外又加了个app配置。我们在Main.scala里实例化DAOs时可以用typesafe-config读取app.dbconfig值后设定jdbcDriver和db:

 1   object Actions extends DAOs with DBConfig {
 2     import slick.util.ClassLoaderUtil
 3     import scala.util.control.NonFatal
 4     import com.typesafe.config.ConfigFactory
 5 
 6     def getDbConfig: String =
 7         ConfigFactory.load().getString("app.dbconfig")
 8 
 9     def getDbDriver(path: String): JdbcProfile = {
10       val config = ConfigFactory.load()
11       val n = config.getString((if (path.isEmpty) "" else path + ".") + "driver")
12       val untypedP = try {
13         if (n.endsWith("$")) ClassLoaderUtil.defaultClassLoader.loadClass(n).getField("MODULE$").get(null)
14         else ClassLoaderUtil.defaultClassLoader.loadClass(n).newInstance()
15       } catch {
16         case NonFatal(ex) =>
17           throw new SlickException(s"""Error getting instance of Slick driver "$n"""", ex)
18       }
19       untypedP.asInstanceOf[JdbcProfile]
20     }
21     
22     override lazy val jdbcDriver: JdbcProfile = getDbDriver(getDbConfig)
23     val dbConf: DatabaseConfig[JdbcProfile] = DatabaseConfig.forConfig(getDbConfig)
24     override val db = dbConf.db
25   }

现在我们只需要改变application.conf里的app.dbconfig就可以转换目标数据库参数了。实际上,除了数据库配置,我们还可以在application.conf里进行其它类型的配置。然后用typesafe-config实时读取。如果不想在application.conf进行数据库之外的配置,可以把其它配置放在任何文件里,然后用ConfigFactory.load(path)来读取。

另外,在软件开发过程中跟踪除错也是很重要的。我们可以用logback来跟踪Slick、HikariCP等库的运行状态。logback配置在src/main/resources/logback.xml:

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 
 3 <configuration>
 4     <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
 5         <encoder>
 6             <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
 7         </encoder>
 8     </appender>
 9 
10     <logger name="application" level="DEBUG"/>
11     <logger name="com.zaxxer.hikari" level="DEBUG"/>
12     <logger name="slick" level="DEBUG"/>
13 
14     <root level="DEBUG">
15         <appender-ref ref="STDOUT"/>
16     </root>
17 </configuration>

DEBUG值可以显示最详细的状态信息。

好了,我把这次示范代码提供在下面:

build.sbt:

 1 name := "learn-slick301"
 2 
 3 version := "1.0"
 4 
 5 scalaVersion := "2.11.8"
 6 
 7 libraryDependencies ++= Seq(
 8   "com.typesafe.slick" %% "slick" % "3.1.1",
 9   "com.h2database" % "h2" % "1.4.191",
10   "com.typesafe.slick" %% "slick-hikaricp" % "3.1.1",
11   "ch.qos.logback" % "logback-classic" % "1.1.7",
12   "org.typelevel" %% "cats" % "0.7.2"
13 
14 )

src/main/resources/

application.conf:

 1 app = {
 2   dbconfig = h2
 3 }
 4 
 5 h2 {
 6   driver = "slick.driver.H2Driver$"
 7   db {
 8     url = "jdbc:h2:~/slickdemo;mv_store=false"
 9     driver = "org.h2.Driver"
10     connectionPool = HikariCP
11     numThreads = 10
12     maxConnections = 12
13     minConnections = 4
14     keepAliveConnection = true
15   }
16 }
17 
18 h2mem = {
19   url = "jdbc:h2:mem:slickdemo"
20   driver = org.h2.Driver
21   connectionPool = disabled
22   keepAliveConnection = true
23 }
24 
25 mysql {
26   driver = "slick.driver.MySQLDriver$"
27   db {
28     url = "jdbc:mysql://localhost/slickdemo"
29     driver = com.mysql.jdbc.Driver
30     keepAliveConnection = true
31     user="root"
32     password="123"
33     numThreads=10
34     maxConnections = 12
35     minConnections = 4
36   }
37 }
38 
39 mysqldb = {
40   dataSourceClass = "com.mysql.jdbc.jdbc2.optional.MysqlDataSource"
41   properties {
42     user = "root"
43     password = "123"
44     databaseName = "slickdemo"
45     serverName = "localhost"
46   }
47   numThreads = 10
48   maxConnections = 12
49   minConnections = 4
50 }
51 
52 postgres {
53   driver = "slick.driver.PostgresDriver$"
54   db {
55     url = "jdbc:postgresql://127.0.0.1/slickdemo"
56     driver = "org.postgresql.Driver"
57     connectionPool = HikariCP
58     user = "slick"
59     password = "123"
60     numThreads = 10
61     maxConnections = 12
62     minConnections = 4
63   }
64 }
65 
66 postgressdb = {
67   dataSourceClass = "org.postgresql.ds.PGSimpleDataSource"
68   properties = {
69     databaseName = "slickdemo"
70     user = "slick"
71     password = "123"
72   }
73   connectionPool = HikariCP
74   numThreads = 10
75   maxConnections = 12
76   minConnections = 4
77 }
78 
79 mssql {
80   driver = "com.typesafe.slick.driver.ms.SQLServerDriver$"
81   db {
82     url = "jdbc:sqlserver://host:port"
83     driver = com.microsoft.sqlserver.jdbc.SQLServerDriver
84     connectionTimeout = 30 second
85     connectionPool = HikariCP
86     user = "slick"
87     password = "123"
88     numThreads = 10
89     maxConnections = 12
90     minConnections = 4
91     keepAliveConnection = true
92   }
93 }
94 
95 tsql {
96   driver = "slick.driver.H2Driver$"
97   db = ${h2mem}
98 }

logback.xml:

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 
 3 <configuration>
 4     <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
 5         <encoder>
 6             <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
 7         </encoder>
 8     </appender>
 9 
10     <logger name="application" level="DEBUG"/>
11     <logger name="com.zaxxer.hikari" level="DEBUG"/>
12     <logger name="slick" level="DEBUG"/>
13 
14     <root level="DEBUG">
15         <appender-ref ref="STDOUT"/>
16     </root>
17 </configuration>

src/main/scala/config/AppConfig.scala:

1 package com.bayakala.learn.slick301.config
2 import slick.driver.JdbcProfile
3 trait DBConfig {
4   val jdbcDriver: JdbcProfile
5   import jdbcDriver.api._
6   val db: Database
7 }

src/main/scala/model/TableDefs.scala:

 1 package com.bayakala.learn.slick301.model
 2 import slick.driver.JdbcProfile
 3 class TableDefs(val dbDriver: JdbcProfile) {
 4   import dbDriver.api._
 5   case class Supplier(id: Long
 6                       , name: String
 7                       , contact: Option[String]
 8                       , website: Option[String])
 9   final class Suppliers(tag: Tag) extends Table[Supplier](tag,"SUPPLERS") {
10     def id = column[Long]("ID",O.AutoInc,O.PrimaryKey)
11     def name = column[String]("NAME")
12     def contact = column[Option[String]]("CONTACT")
13     def website = column[Option[String]]("WEBSITE")
14     def * = (id, name, contact, website) <> (Supplier.tupled,Supplier.unapply)
15     def nidx = index("NM_IDX",name,unique = true)
16   }
17   val suppliers = TableQuery[Suppliers]
18 
19   case class Coffee(id: Long
20                      ,name: String
21                      ,supid: Long
22                      ,price: Double
23                      ,sales: Int)
24   final class Coffees(tag: Tag) extends Table[Coffee](tag, "COFFEES") {
25     def id = column[Long]("ID",O.AutoInc,O.PrimaryKey)
26     def name = column[String]("NAME")
27     def supid = column[Long]("SUPID")
28     def price = column[Double]("PRICE",O.Default(0.0))
29     def sales = column[Int]("SALES",O.Default(0))
30     def * = (id,name,supid,price,sales) <> (Coffee.tupled, Coffee.unapply)
31     def fk_sup = foreignKey("FK_SUP",supid,suppliers)(_.id,onDelete = ForeignKeyAction.Restrict,onUpdate = ForeignKeyAction.Cascade)
32     def supidx = index("SUP_IDX",supid,unique = false)
33     def nidx = index("NM_IDX",name,unique = true)
34   }
35   val coffees = TableQuery[Coffees]
36 
37 }

src/main/scala/access/DAOs.scala:

 1 package com.bayakala.learn.slick301.access
 2 import com.bayakala.learn.slick301.config
 3 import com.bayakala.learn.slick301.config.DBConfig
 4 import com.bayakala.learn.slick301.model.TableDefs
 5 trait DAOs { dbconf: DBConfig =>
 6   import jdbcDriver.api._
 7   //注入依赖
 8   val tables = new TableDefs(dbconf.jdbcDriver)
 9   import tables._
10   //suppliers queries
11   val createSupplierTable = suppliers.schema.create
12   val allSuppliers = suppliers.result
13   def insertSupplier(id:Long,name:String,address:Option[String],website:Option[String])
14   = suppliers += Supplier(id,name,address,website)
15   def insertSupbyName(n: String) = suppliers.map(_.name) += n
16   //coffees queries
17   val createCoffeeTable = coffees.schema.create
18   val allCoffees = coffees.result
19   def insertCoffee(c: (Long,String,Long,Double,Int)) =
20     coffees += Coffee(id=c._1, name=c._2,supid=c._3,price=c._4,sales=c._5)
21 
22 }

src/main/scala/main/Main.scala:

 1 package com.bayakala.learn.slick301.main
 2 import com.bayakala.learn.slick301.config.DBConfig
 3 import com.bayakala.learn.slick301.access.DAOs
 4 
 5 import scala.concurrent.Await
 6 import scala.util.{Failure, Success}
 7 import scala.concurrent.duration._
 8 import scala.concurrent.ExecutionContext.Implicits.global
 9 import slick.backend.DatabaseConfig
10 import slick.driver.JdbcProfile
11 
12 object Main {
13 
14   object Actions extends DAOs with DBConfig {
15     import slick.SlickException
16     import slick.util.ClassLoaderUtil
17     import scala.util.control.NonFatal
18     import com.typesafe.config.ConfigFactory
19 
20     def getDbConfig: String =
21         ConfigFactory.load().getString("app.dbconfig")
22 
23     def getDbDriver(path: String): JdbcProfile = {
24       val config = ConfigFactory.load()
25       val n = config.getString((if (path.isEmpty) "" else path + ".") + "driver")
26       val untypedP = try {
27         if (n.endsWith("$")) ClassLoaderUtil.defaultClassLoader.loadClass(n).getField("MODULE$").get(null)
28         else ClassLoaderUtil.defaultClassLoader.loadClass(n).newInstance()
29       } catch {
30         case NonFatal(ex) =>
31           throw new SlickException(s"""Error getting instance of Slick driver "$n"""", ex)
32       }
33       untypedP.asInstanceOf[JdbcProfile]
34     }
35 
36     override lazy val jdbcDriver: JdbcProfile = getDbDriver(getDbConfig)
37     val dbConf: DatabaseConfig[JdbcProfile] = DatabaseConfig.forConfig(getDbConfig)
38     override val db = dbConf.db
39   }
40   import Actions._
41 
42 
43   def main(args: Array[String]) = {
44 
45     val res = db.run(createSupplierTable).andThen {
46       case Success(_) => println("supplier table created")
47       case Failure(_) => println("unable to create supplier table")
48     }
49     Await.ready(res, 3 seconds)
50 
51     val res2 = db.run(insertSupbyName("Acme Coffee Co."))
52     Await.ready(res2, 3 seconds)
53 
54     Await.ready(db.run(allSuppliers), 10 seconds).foreach(println)
55 
56     val res10 = db.run(createCoffeeTable).andThen {
57       case Success(_) => println("coffee table created")
58       case Failure(_) => println("unable to create coffee table")
59     }
60     Await.ready(res10, 3 seconds)
61 
62     val res11 = db.run(insertCoffee((101,"Columbia",1,158.0,0)))
63     Await.ready(res11, 3 seconds)
64 
65     Await.ready(db.run(allCoffees), 10 seconds).foreach(println)
66 
67   }

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