拥抱Java8第一弹

package creative.air.java8.common;

import java.time.LocalDate;
import java.time.Period;
import java.time.format.DateTimeFormatter;
import java.time.temporal.ChronoUnit;
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;
import java.util.function.Predicate;
import java.util.stream.IntStream;

/**
 * A First Taste for JDK8
 * Created by [e-mail]
 * Date: Jan 16 2014
 * Time: 2:02 PM
 */
public class FirstApp {

    @FunctionalInterface
    public interface Task {
        void run();

        /*1. given default method in functional interface(or a SAM type)*/
        default void cancel() {
        }
    }

    public static void schedule(Task task) {
        task.run();
    }

    public static void main(String[] args) {
        /*2. Lambda Expressions for anonymous class*/
        {
            /*
            schedule(new Task() {
                @Override
                public void run() {
                    System.out.println("Hello world!");
                }
            });
            */
            schedule(() -> {
                System.out.println("Hello world!");
            });
        }
        List<String> versions = Arrays.asList("JDK7", "JDK8");
         /*3. method reference :: 126 Lambda Expressions & Virtual Extension Methods*/
        {
            /*
            versions.sort(new Comparator<String>() {
                @Override
                public int compare(String o1, String o2) {
                    return o2.compareTo(o1);
                }
            });
            */
            /*
            versions.sort((o1, o2) -> o1.compareTo(o2));
            */
            Comparator<? super String> comparator = String::compareTo;
            versions.sort(comparator);
            System.out.println("JDK versions:" + versions);
        }

        /*4. 107 Bulk Data Operations for Collections*/
        {
            /*
            versions.parallelStream().filter(
              s -> s.equals("JDK8")
            ).map(
              s -> "Develop in " + s + " with Pleasure!"
            ).forEach(
              System.out::println
            );
            */
            Predicate<? super String> predicate = s -> s.equals("JDK8");
            versions.parallelStream().filter(predicate).map(
              s -> String.format("Develop in %s with Pleasure!", s)
            ).forEach(
              System.out::println
            );

            IntStream range = IntStream.range(101, 150);
            range.parallel().filter(i -> i % 10 == 0).sequential().forEach(System.out::println);
        }

        /*JSR 310*/
        {
            Period period = Period.between(LocalDate.parse("1979-03-03"), LocalDate.now());
            System.out.printf("my age is:%d%n", period.getYears());

            System.out.printf("Touch JSR310 %s.%n", LocalDate.of(2014, 1, 16));

            LocalDate bjDate = LocalDate.of(2004, 8, 26);
            System.out.println(bjDate.plus(9, ChronoUnit.YEARS)
              .plus(6, ChronoUnit.MONTHS)
              .plus(5, ChronoUnit.DAYS).format(DateTimeFormatter.ofPattern("E MM/dd/yyyy")));
        }
    }
}

 

评论

7 楼 marshan 2014-01-22  

我这里只是抛砖引玉 希望多多交流哈

6 楼 satuo20 2014-01-18  

总觉得java不应该出现类似'->'这样的操作符，太不人性化了，而且可可读性也会变得很差。除非是能换来高性能。

5 楼 bitray 2014-01-18  

panda0001 写道

这还是java吗

你可以认为是代码的内聚性和封装性更高了。跟过去的匿名内部类很像的

4 楼 sootv 2014-01-18  

我怎么感觉好乱

3 楼 panda0001 2014-01-17  

这还是java吗

2 楼 alvin198761 2014-01-17  

java 7都没有搞定，java 8就来了

1 楼 white_crucifix 2014-01-17  

看上去很好玩哎，好想玩一下，java越来越与时俱进了