1.行为参数化,就是一个方法接受多个不同的行为作为参数,并在内部使用它们,完成不同行为的能力
2.行为参数化可以让代码个好的适应不断变化的要求,减轻工作量
3.lambda表达式是这一应用更加简便
4.掌握分析谓词,定义出合适的接口和实现方法
public static class Apple{ private String color; private Integer weight; private String sm; public String getSm() { return sm; } public void setSm(String sm) { this.sm = sm; } public Apple(String color, int weight) { this.color = color; this.weight = weight; } @Override public String toString() { return "Apple{" + "color='" + color + '\'' +", weight=" + weight +", sm='" + sm + '\'' +'}'; } public String getColor() { return color; } public void setColor(String color) { this.color = color; } public Integer getWeight() { return weight; } public void setWeight(Integer weight) { this.weight = weight; } } //从列表中筛选出绿色的苹果 public static List<Apple> filterGreenApple(List<Apple>inventory){ List<Apple>result=new ArrayList<>(); for (Apple apple : inventory) { if ("green".equals(apple.getColor())) { result.add(apple); } } return result; } //从列表中根据参数筛选出绿色的苹果 public static List<Apple>filerAppleByColor(List<Apple>appleList,String color){ List<Apple> apples=new ArrayList<>(); for (Apple apple : appleList) { if (apple.getColor().equals(color)) { apples.add(apple); } } return apples; } //统一定义行为参数接口类,这个行为的主体是apple public interface ApplePredicate{ boolean test(Apple apple); } public interface PredicateFormat{ String accept(Apple apple); } //定义泛型类的行为参数接口类,这个行为的主体不在局限某一个实物 public interface AbstratPredicate<T>{ boolean test(T t); } //参数行为化多实现类写法,实现按重量和颜色挑选苹果 public static class filterGreenWeightApple implements ApplePredicate{ @Override public boolean test(Apple apple) { return apple.getColor().equals("green")&&apple.getWeight()>100; } } public static class filteFannyApple implements PredicateFormat{ @Override public String accept(Apple apple) { String ss= apple.getWeight()>100? "light":"heavy"; return "A"+ ss+apple.getColor()+"Apple"; } } public static List<Apple>filterApplePredicate(List<Apple> appleList,ApplePredicate p){ List<Apple> apples=new ArrayList<>(); for (Apple apple : appleList) { if (p.test(apple)) { apples.add(apple); } } return apples; } public static List<Apple>filterFannyApple(List<Apple>appleList,PredicateFormat p){ List<Apple>apples=new ArrayList<>(); for (Apple apple : appleList) { apple.setSm(p.accept(apple)); apples.add(apple); } return apples; } //集成泛型接口的泛型类型方法 public static <T> List<T> filter(List<T>list,AbstratPredicate<T> pa){ List<T>lists=new ArrayList<>(); for (T t : list) { if (pa.test(t)) { lists.add(t); } } return lists; } //匿名类的笨重感 public static class MeaningOfThis{ public final int value=4; public void doIt(){ int value=6; Runnable r=new Runnable() { public final int value=5; @Override public void run() { int value=10; System.out.println(this.value); } }; r.run(); } } public static void main(String[] args) { List<Apple> appleList=Arrays.asList(new Apple("yellow",150),new Apple("green",150),new Apple("green",100)); //过滤绿色的苹果 List<Apple>result=filterGreenApple(appleList); result.stream().forEach((Apple a)->System.out.println(a)); //根据颜色参数过滤苹果 List<Apple>colorResult=filerAppleByColor(appleList,"yellow"); colorResult.stream().forEach(c->System.out.println(c)); //参数行为化多实现类写法,实现按重量和颜色挑选苹果 List<Apple>colorWeightApple=filterApplePredicate(appleList,new filterGreenWeightApple() ); colorWeightApple.stream().forEach(cw->System.out.println(cw)); List<Apple>fannyApple=filterFannyApple(appleList,new filteFannyApple()); fannyApple.stream().forEach(f->System.out.println(f)); System.out.println("-----------------------------"); //参数行为化匿名类实现 List<Apple>niming=filterApplePredicate(appleList, new ApplePredicate() { @Override public boolean test(Apple apple) { return apple.getColor().equals("green"); } }); niming.stream().forEach(n->System.out.println(n)); //匿名类的笨重感 MeaningOfThis mo=new MeaningOfThis(); mo.doIt(); //lambda表达式改写 System.out.println("-------我是lambda---------"); List<Apple>lamApples=filterApplePredicate(appleList,(Apple a)->a.getWeight()>100); lamApples.stream().forEach(la->System.out.println(la)); System.out.println("---------------"); List<Apple>lamApples1= filterFannyApple(appleList,(Apple a)->{ String ss=a.getWeight()>100?"lighter":"heavyer"; return "A"+ss+a.getColor()+"Apple"; }); lamApples1.sort((Apple a,Apple a1)->{ if (!a1.getWeight().equals(a.getWeight())) { return a1.getWeight().compareTo(a.getWeight()); }else { return a1.getColor().compareTo(a.getColor()); } }); lamApples1.stream().forEach(la1->System.out.println(la1)); //集成泛型接口的泛型类型方法 List<Integer>nums= Arrays.asList(1,2,3,4,5,6); List<Integer>numlist=filter(nums,(Integer i)->i%2==0); numlist.sort((Integer a,Integer a1)->a.compareTo(a1)); numlist.stream().forEach(i->System.out.println(i)); //自带的排序行为参数化的排序 Thread t=new Thread(()->System.out.println(new Apple("red",100))); t.start(); }
以上就是浅谈JAVA8中行为参数化的演变过程的详细内容,更多请关注php中文网其它相关文章!
已抢185737个
抢已抢66896个
抢已抢352235个
抢已抢665711个
抢已抢120217个
抢已抢20623个
抢