java8 Optional优雅非空判断

java8 Optional优雅非空判断

import java.util.ArrayList;


import java.util.List;


import java.util.Optional;


public class OptionalTest {


    public static void main(String[] args) {


        String str = null;


        Optional<String> opt = Optional.ofNullable(str);


        opt.ifPresent(n -> {


            System.out.println(n);


        });


        List<String> strs = new ArrayList<String>();


        strs.add("1");


        strs.add("2");


        Optional<List<String>> opts = Optional.ofNullable(strs);


        opts.ifPresent(opt -> {


            opt.forEach(n -> {


                System.out.println(n);


            });


        });


    }


}