Practical skills: How to use the Slick CodeGen framework to improve the maintenance of the Java library
Practical skills: How to use the Slick CodeGen framework to improve the maintenance of the Java library
Brief introduction
In modern software development, maintenance is a vital concept.When a Java library is easy to understand, modify and expand, it will greatly improve the work efficiency of developers.This article will introduce how to use the SLICK CodeGen framework to generate the Java class library that is easy to maintain and use example descriptions.
What is the Slick CodeGen framework?
Slick CodeGen is a Java class library. It uses a simple template engine syntax and automatically generates the Java class according to the database model defined in the configuration file.It provides many functions, such as associations, field verification, and data access layer code.By using Slick CodeGen, we can define the Java class from the database, thereby reducing the workload of manually writing repeated and error -prone code.
Step 1: Configure build.sbt file
First of all, we need to add Slick CodeGen to the project's Build.sbt file.Add the following content to DependenCies:
scala
libraryDependencies += "com.typesafe.slick" %% "slick-codegen" % "3.3.3"
libraryDependencies += "com.typesafe.slick" %% "slick-hikaricp" % "3.3.3"
Step 2: Create a database model definition
Second, we need to create a database model definition file.This file describes the relationship between the table and the table in the database.For example, we have a table called "Users", which contains three fields: "ID", "name" and "email".We can name the model definition file "Tables.scala" and add the following:
import slick.jdbc.H2Profile.api._
class User(tag: Tag) extends Table[(Int, String, String)](tag, "users") {
def id = column[Int]("id", O.PrimaryKey)
def name = column[String]("name")
def email = column[String]("email")
def * = (id, name, email)
}
object Tables {
val users = TableQuery[User]
}
Step 3: Writing code generate script
Next, we need to write a code generating script to generate the Java class.Create a file called "CodeGen.scala" and add the following content:
import slick.jdbc.H2Profile.api._
import slick.codegen.SourceCodeGenerator
object Codegen extends App {
val db = Database.forConfig("h2mem1")
val generator = new SourceCodeGenerator(db.getProfile)
generator.writeToFile(
profile = "slick.jdbc.H2Profile",
folder = "output",
pkg = "com.example.generated",
fileName = "Tables.scala"
)
}
In the above code, we first use the `database.forconfig` method to create a database instance.Then, we instantiated an object of `SourceCodeGENATOR` and was introduced into the profile of the database.Finally, we use the path, package name, and file name of the file generated by the `` writetofile "method.
Step 4: Generate java class
Now, we can execute the code to generate a script and generate the Java class.Run the following command in the terminal:
shell
sbt run
After the running is successful, the "TABLES.SCALA" file is generated in the "Output" folder of the project root directory, which contains the Java class generated according to the database model.
in conclusion
By using the Slick CodeGen framework, we can easily generate the Java class library that is easy to maintain.In this way, we can save a lot of time to write duplicate code and improve the readability and maintenance of the code.In actual projects, the specific database model definition can be combined with a customized Java class to meet the needs of the project.
In short, Slick CodeGen is a powerful tool that helps developers to quickly generate maintainable Java libraries to improve code quality and development efficiency.
The above is the practical technique of using the Slick CodeGen framework to improve the maintenanceability of the Java library.Hope to help you!
