【有点东西】将20位学生进行分班，每个班最多8个学生

talk is cheap, show me the code.

应用场景

对一批物品开增值税专票时，限制每张专票最多有8个明细项；
开增值税普票时，限制每张发票最多有200个明细项；

这时我们对这一批物品进行开票时，程序就需要能做到自动拆分成多张发票。

需求及功能实现

将20位学生进行分班，每个班最多8个学生

import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;

/**
 * 需求：将20位学生进行分班，每个班最多8个学生
 */
public class Main {

    public static void main(String[] args) {
        // 初始化班级容器
        LinkedList<SchoolClass> schoolClasses = initializeSchoolClasses();
        // 所有学生
        List<Student> allStudents = getAllStudents();
        
        // 遍历学生，进行分班
        for (Student currentStudent : allStudents) {
            SchoolClass currentClass = schoolClasses.getLast();
            // 班级学生人数超过8人，增加班级
            if (currentClass.getStudents().size() >= 8) {
                SchoolClass newSchoolClass = new SchoolClass(new ArrayList<>());
                schoolClasses.addLast(newSchoolClass);
                currentClass = newSchoolClass;
            }
            // 学生进入班级
            currentClass.getStudents().add(currentStudent);
        }

        for (SchoolClass schoolClass : schoolClasses) {
            System.out.println("=============================");
            for (Student student : schoolClass.getStudents()) {
                System.out.println(student);
            }
        }
    }

    /**
     * 初始化班级容器，默认有一个班级
     * 选用{@link LinkedList}作为容器，方便获取最后一个元素
     *
     * @return
     */
    private static LinkedList<SchoolClass> initializeSchoolClasses() {
        LinkedList<SchoolClass> schoolClasses = new LinkedList<>();
        schoolClasses.add(new SchoolClass(new ArrayList<>()));
        return schoolClasses;
    }

    private static List<Student> getAllStudents() {
        List<Student> allStudents = new ArrayList<>();
        for (int i = 1; i <= 20; i++) {
            allStudents.add(new Student(i, "王" + i, 18, "男", "重庆市南岸区茶园路" + i + "号"));
        }
        return allStudents;
    }

}

控制台输出

=============================
Student(id=1, name=王1, age=18, sex=男, address=重庆市南岸区茶园路1号)
Student(id=2, name=王2, age=18, sex=男, address=重庆市南岸区茶园路2号)
Student(id=3, name=王3, age=18, sex=男, address=重庆市南岸区茶园路3号)
Student(id=4, name=王4, age=18, sex=男, address=重庆市南岸区茶园路4号)
Student(id=5, name=王5, age=18, sex=男, address=重庆市南岸区茶园路5号)
Student(id=6, name=王6, age=18, sex=男, address=重庆市南岸区茶园路6号)
Student(id=7, name=王7, age=18, sex=男, address=重庆市南岸区茶园路7号)
Student(id=8, name=王8, age=18, sex=男, address=重庆市南岸区茶园路8号)
=============================
Student(id=9, name=王9, age=18, sex=男, address=重庆市南岸区茶园路9号)
Student(id=10, name=王10, age=18, sex=男, address=重庆市南岸区茶园路10号)
Student(id=11, name=王11, age=18, sex=男, address=重庆市南岸区茶园路11号)
Student(id=12, name=王12, age=18, sex=男, address=重庆市南岸区茶园路12号)
Student(id=13, name=王13, age=18, sex=男, address=重庆市南岸区茶园路13号)
Student(id=14, name=王14, age=18, sex=男, address=重庆市南岸区茶园路14号)
Student(id=15, name=王15, age=18, sex=男, address=重庆市南岸区茶园路15号)
Student(id=16, name=王16, age=18, sex=男, address=重庆市南岸区茶园路16号)
=============================
Student(id=17, name=王17, age=18, sex=男, address=重庆市南岸区茶园路17号)
Student(id=18, name=王18, age=18, sex=男, address=重庆市南岸区茶园路18号)
Student(id=19, name=王19, age=18, sex=男, address=重庆市南岸区茶园路19号)
Student(id=20, name=王20, age=18, sex=男, address=重庆市南岸区茶园路20号)

可以看到，成功将20位学生分到了三个班级，且每个班最多8个学生，完成需求。

POJO

SchoolClass.java

import lombok.AllArgsConstructor;
import lombok.Data;

import java.util.List;

@Data
@AllArgsConstructor
public class SchoolClass {
    private List<Student> students;
}

Student.java

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@NoArgsConstructor
@AllArgsConstructor
public class Student {
    private Integer id;
    private String name;
    private Integer age;
    private String sex;
    private String address;
}