Java8 stream()常用方法

╰半夏微凉° 2021-09-25 04:42 308阅读 0赞

public class StreamDemo {
    
       static class Student{
            private int age;
    
            public Student(int age){
                this.age = age;
            }
    
            public int getAge() {
                return age;
            }
    
            public void setAge(int age) {
                this.age = age;
            }
        }
    
        public static void main(String[] args) {
            List<Long> streamList = Arrays.asList(2L,3L,4L,5L,6L,2L,3L,4L);
    
            //遍历
            List<Long> longList = streamList.stream().collect(Collectors.toList());
            //longList.forEach(System.out::print);
    
            //筛选
            List<Long> longList1 = streamList.stream().filter(o -> o>3).collect(Collectors.toList());
           // longList1.forEach(System.out::print);
    
            //去重
            List<Long> longList2 = longList1.stream().distinct().collect(Collectors.toList());
            //longList2.forEach(System.out::print);
    
            //排序
            List<Long> longList3 = streamList.stream().sorted().collect(Collectors.toList());
            //longList3.forEach(System.out::print);
    
            //统计
            long count = streamList.stream().count();
            //System.out.println(count);
    
    
            Student s1 = new Student(20);
            Student s2 = new Student(10);
            List<Student> studentList = Arrays.asList(s1,s2);
    
            //组装一
            List<Integer> ageList = studentList.stream().map(Student::getAge).collect(Collectors.toList());
           // ageList.forEach(System.out::print);
    
            //组装二
            List<String> stringList = Arrays.asList("1,2,3,4","2,3,4,5");
            List<String> longList4 = stringList.stream().map(o -> o.replaceAll(",",""))
                    .collect(Collectors.toList());
            longList4.forEach(System.out::print);
        }
    }