Closed yogjun closed 5 years ago
1创建一个子列表 List numbers = Arrays.asList(1,2,3,6,7,5,5,8,9); List numbers1 = numbers.stream().map(i -> i=2*i).distinct().collect(Collectors.toList()); 2表示迭代 numbers1.forEach(i->System.out.print(i)); 3对列表每个元素应用函数 List str = Arrays.asList("a10","a20","a30","a40"); String aaa= str.stream().map(i->i.toUpperCase()).collect(Collectors.joining("**")); System.out.print(aaa);
4避免 Null 检查 Optional.of(new Outer()) .map(Outer::getNested) .map(Nested::getInner) .map(Inner::getFoo) .ifPresent(System.out::println);
原文：http://www.importnew.com/16436.html http://www.importnew.com/28387.html
1创建一个子列表 List numbers = Arrays.asList(1,2,3,6,7,5,5,8,9);
List numbers1 = numbers.stream().map(i -> i=2*i).distinct().collect(Collectors.toList());
2表示迭代
numbers1.forEach(i->System.out.print(i));
3对列表每个元素应用函数
List str = Arrays.asList("a10","a20","a30","a40");
String aaa= str.stream().map(i->i.toUpperCase()).collect(Collectors.joining("**"));
System.out.print(aaa);
4避免 Null 检查 Optional.of(new Outer()) .map(Outer::getNested) .map(Nested::getInner) .map(Inner::getFoo) .ifPresent(System.out::println);
原文：http://www.importnew.com/16436.html http://www.importnew.com/28387.html