IntToDoubleFunction 是java.util.function包中的功能接口。该功能接口接受一个int值的参数并产生一个double值的结果。IntToDoubleFunction可以用作lambda 表达式 或方法引用的分配目标。它仅包含一个抽象方法：applyAsDouble()。
语法
@FunctionalInterface
interface IntToDoubleFunction {
double applyAsDouble(int value);
}
Lambda表达式示例
import java.util.function.IntToDoubleFunction;;
public class IntToDoubleLambdaTest {
public static void main(String[] args) {
IntToDoubleFunction getDouble = intVal -> {
//lambda表达式
double doubleVal = intVal;
return doubleVal;
};
int input = 25;
double result = getDouble.applyAsDouble(input);
System.out.println("double值是: " + result);
input = 50;
System.out.println("double值是: " + getDouble.applyAsDouble(input));
input = 75;
System.out.println("double值是: " + getDouble.applyAsDouble(input));
}
}
输出结果
double值是: 25.0
double值是: 50.0
double值是: 75.0
方法引用示例
import java.util.function.IntToDoubleFunction;
public class IntToDoubleMethodRefTest {
public static void main(String[] args) {
IntToDoubleFunction result = IntToDoubleMethodRefTest::convertIntToDouble;
//方法引用
System.out.println(result.applyAsDouble(50));
System.out.println(result.applyAsDouble(100));
}
static Double convertIntToDouble(int value) {
return value / 10d;
}
}
输出结果
5.0
10.0
