import java.io.Serializable;
import java.util.*;
import java.util.stream.Collectors;
public class Main {
public static void main(String[] args) {
List<Student> studentList = new ArrayList<>();
studentList.add(new Student(1,2,1000,88));
studentList.add(new Student(2,2,1000,76));
studentList.add(new Student(3,1,2000,79));
studentList.add(new Student(4,2,3000,88));
studentList.add(new Student(5,2,3000,49));
studentList.add(new Student(5,1,4000,69));
studentList.add(new Student(5,1,4000,96));
// 按照班级分组，性别为女，分数降序
Map<String, List<Student>> groupList = new HashMap<String, List<Student>>();
studentList.stream().filter(student ->
student.getSex() == 2
).collect(Collectors.groupingBy(Student::getClassNo,
Collectors.toList())).forEach(
(classNo, listByClassNo) -> {
groupList.put(classNo + "",
listByClassNo.stream().sorted(Comparator.comparing(Student::getScore).reversed()).collect(Collectors.toList()));
}
);
System.out.println("Hello World!");
}
private static class Student implements Serializable {
private int id;
private int sex;
private int classNo;
private int score;
public Student(int id, int sex, int classNo, int score) {
this.id = id;
this.sex = sex;
this.classNo = classNo;
this.score = score;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public int getSex() {
return sex;
}
public void setSex(int sex) {
this.sex = sex;
}
public int getClassNo() {
return classNo;
}
public void setClassNo(int classNo) {
this.classNo = classNo;
}
public int getScore() {
return score;
}
public void setScore(int score) {
this.score = score;
}
}
}
关于JDK8中stream的用法小总结。的相关教程结束。
