JDK8 lameda表達式學習例子

lameda表達式是jdk8出的內容，做爲一名老程序員，一直沒接觸。二次開發git上的一個開源項目，直接淚崩。因而趕忙補補課，直接上學習過程當中的源碼：
package xx.test.lameda;

import java.util.Arrays;
import java.util.List;
import java.util.function.Predicate;

public class LamedaMain {
    public static void main(String[] args) {

        List<String> list= Arrays.asList("danny","fancial","join","jack1");

　　　　　// 建立過濾條件 Predicate可支持and、or、xor組合
        Predicate<String> predicate = (n)->n.startsWith("j");
        Predicate<String> predicate1 = (n)->n.length()==5;

　　　　  //過濾list中字母「j」開頭的元素
        System.out.println("====print start with j");
        list.stream().filter(predicate).forEach(System.out::println);

　　　　  //過濾list中字節長度爲5的元素
        System.out.println("=====print length is 5");
        list.stream().filter(predicate1).forEach(System.out::println);

        //過濾list中字母「j」開頭而且長度爲5的元素
        System.out.println("=======print start with j and length is 5");
        list.stream().filter(predicate.and(predicate1)).forEach(System.out::println);

        //過濾list中字母「j」開頭或者長度爲5的元素        System.out.println("=======print start with j or length is 5");        list.stream().filter(predicate.or(predicate1)).forEach(System.out::println);        //利用stream和map修改doubleList中元素的內容        System.out.println("=======show may operation");        List<Double> doubleList = Arrays.asList(100.0,200.0,300.0,400.0);        doubleList.stream().map(n->n*0.2).forEach(System.out::println);        //利用stream和reduce聚合輸出        System.out.println("========show reduce operation");        System.out.println("sum is "+doubleList.stream().map(n->n*0.2).reduce((sum,n)->sum+n).get());        List<Integer> integerList = Arrays.asList(100,200,300,400);        System.out.println("max is "+integerList.stream().reduce(Integer::max).get());        System.out.println("min is "+integerList.stream().reduce(Integer::min).get());        System.out.println("sum is "+integerList.stream().reduce(Integer::sum).get());    }}