lambda表达式的简单使用

package com.mytest;
import java.util.Arrays;
import java.util.List;
import java.util.function.Predicate;

public class LambdaTest {

    public static void main(String[] args) {
        List<String> strings = Arrays.asList("java","javaqwer","jsdfava", "merry", "tomorrow", "day");

        System.out.println("which start with j:");

        filter2(strings, (lan) -> lan.startsWith("j"));
        filter(strings, (str) -> str.startsWith("J"));
        System.out.println("Languages which ends with a ");
        filter(strings, (str) -> str.endsWith("a"));

        System.out.println("Languages which length>5");
        filter(strings, (str) -> str.length() > 5);

        System.out.println("Languages which contains a");
        filter(strings, (str) -> str.contains("a"));


        System.out.println("==========逻辑函数合并使用==========");
        //逻辑函数合并使用
        strings.stream().filter(startsWithJ.and(lengthOverFour)).forEach(str-> System.out.println(str));

    }

　　//常规方式
    private static void filter(List<String> strings, Predicate<String> condition) {
        for (String string : strings) {
            if (condition.test(string)) {
                System.out.println(string);
            }
        }
    }
　　
　　//filter方法的改进版本
    private static void filter2(List<String> strings, Predicate<String> condition) {
        strings.stream().filter(str -> (condition.test(str))).forEach(str -> System.out.println(str));
    }
　　
　　//Predicate允许多个合成一个，它提供了逻辑操作 and，or等方法，把这些拼接起来传入filter()方法中。如主函数方法中的最后一行代码
    static Predicate<String> startsWithJ = (n) -> n.startsWith("j");
    static Predicate<String> lengthOverFour = (n) -> n.length() > 4;
}