java8 Function函数编程详解

java8 Function函数编程详解

Function函数基础定义和使用

    public static void t1(){
        Function<Integer,Integer> calSum= x -> x+2;
        Integer apply = calSum.apply(2);
        System.out.println(apply);
    }

执行结果：

4

多个Function的执行

    public static void t2(){
        Function<Integer,Integer> calFn1= x -> x+2;
        Function<Integer,Integer> calFn2= x -> x*10;
        //先算calFn2 在执行calF1
        Integer apply = calFn1.compose(calFn2).apply(4);
        System.out.println(apply);

        //先算calFn1 在执行calF2
        Integer apply1 = calFn1.andThen(calFn2).apply(4);
        System.out.println(apply1);
    }

执行结果：

42
60

Function对象操作

对象

import lombok.Data;

/**
 * 汽车
 */
@Data
public class Car {

   private String name;
   private String company;
   private Integer status;
    /**
     * 设置名称并返回当前对象
     * @param name
     * @return
     */
    public Car setName(String name){
        this.name=name;
        return this;
    }

    /**
     * 设置公司并返回当前类
     * @param company
     * @return
     */
    public Car setCompany(String company){
        this.company=company;
        return this;
    }

    @Override
    public String toString() {
        return "name:"+name+" company:"+company;
    }
}

对象处理函数

    public static void  t3(){
        Function<Car,Car> setNameFn=car->{
            car.setName("长城");
            return car;
        };
        Function<Car,Car> setSecondNameFn=car->{
            car.setName(car.getName()+"H6");
            return car;
        };

        Car apply = setNameFn.andThen(setSecondNameFn).apply(new Car());
        System.out.println(apply);
    }

执行结果：

name:长城H6 company:null