Scala Interface Description
Scala Interface affirmed
Case
package test2
object TeaitDemo2 {
def main(args: Array[String]): Unit = {
val c = new C()
c.aWay1()
c.getConnec()
val f = new F()
f.getConnec()
}
}
trait Trait01 {
def getConnec()
}
class A {
def aWay1() = {
println("a away")
}
}
class B extends A {
}
class C extends A with Trait01 {
override def getConnec(): Unit = {
println("连接mysql...")
}
}
class D {
}
class E extends D {
}
class F extends D with Trait01 {
override def getConnec(): Unit = {
println("连接oracle...")
}
}
package test3
object TraitDemo3 {
def main(args: Array[String]): Unit = {
val sheep = new Sheep
sheep.sayHi()
sheep.sayHello()
}
}
trait Trait03 {
// 抽象方法
def sayHi()
// 实现普通方法
def sayHello() = {
println("say hello ...")
}
}
class Sheep extends Trait03 {
override def sayHi(): Unit = {
println("小绵羊 喕喕喕喕喕")
}
}
package test4
object MixInDemo {
def main(args: Array[String]): Unit = {
val oracleDB = new OracleDB with Operate3
oracleDB.insert(100)
val mysql = new Mysql with Operate3
mysql.insert(200)
val mysql_ = new Mysql_ with Operate3 {
override def say(): Unit = {
println("say hi")
}
}
mysql_.insert(999)
mysql_.say()
}
}
trait Operate3 {
def insert(id:Int) = {
println("插入数据 = " + id)
}
}
class OracleDB {
}
abstract class Mysql {
}
abstract class Mysql_ {
def say()
}
package test5
object AddTraits {
def main(args: Array[String]): Unit = {
val mySQL4 = new MySQL4 with DB4 with File4
mySQL4.insert(100)
}
}
trait Operate4 {
def insert(id:Int)
}
trait Data4 extends Operate4 {
println("Data4")
override def insert(id: Int): Unit = {
println("插入数据："+ id)
}
}
trait DB4 extends Data4 {
println("DB 4")
override def insert(id: Int): Unit = {
println("向数据库")
super.insert(id)
}
}
trait File4 extends Data4 {
println("File4")
override def insert(id: Int): Unit = {
println("向文件")
super.insert(id)
}
}
class MySQL4 {
}
Note superposition characteristics
Rich Interface
The interface in both abstract methods have non-abstract method
package test6
trait Operate {
def insert (id:Int)
def pageQuery(start:Int,end:Int) = {
println("分页查询")
}
}
package test6
class MyTest extends Operate {
override def insert(id: Int): Unit = {
println("实现方法")
}
override def pageQuery(start: Int, end: Int): Unit = {
println("重新非抽象方法")
}
}
package test6
object Test {
def main(args: Array[String]): Unit = {
val test1 = new MyTest
test1.insert(666)
test1.pageQuery(0,10)
}
}
The specific nature of the field
package test7
object MixInPro {
def main(args: Array[String]): Unit = {
val mySQL6 = new MySQL6 with DB6 {
override var sal: Int = 100
}
println(mySQL6.sal)
println(mySQL6.opertype)
}
}
trait DB6 {
var sal:Int
var opertype:String = "insert"
def insert() = {
}
}
class MySQL6 {
}
Their type
package test8
class MyBean {
def sayHi(): Unit ={
println("hi")
}
}
package test8
object SelfTypeDemo {
def main(args: Array[String]): Unit = {
}
}
trait Logger {
this:Exception =>
def log() = {
println(getMessage)
}
}
package test8
object SelfTest {
def main(args: Array[String]): Unit = {
val student = new Student
student.sayHi()
}
}
trait MyTest {
this:MyBean=>
def say() = {
this.sayHi()
}
}
//class S extends MyTest {} 语法错误
class Student extends MyBean with MyTest {
}
