Java中面向对象的分拣存储-白红宇

Java中面向对象的分拣存储

阅读量：4334 次

发布时间：2019-06-07

本文共 3613 字，大约阅读时间需要 12 分钟。

Student.java

package yzhou.map;/** * 学生类 *  *  * @author 洋 * */public class Student{    private String name;    private String no;    private double score;    public Student()    {            }    public Student(String name, String no, double score)    {        super();        this.name = name;        this.no = no;        this.score = score;    }    public String getName()    {        return name;    }    public void setName(String name)    {        this.name = name;    }    public String getNo()    {        return no;    }    public void setNo(String no)    {        this.no = no;    }    public double getScore()    {        return score;    }    public void setScore(double score)    {        this.score = score;    }            }

ClassRoom.java

package yzhou.map;import java.util.ArrayList;import java.util.List;/** * 一个班级 多个学生 * @author 洋 * */public class ClassRoom{    private String no;    private List
     
       stuList;    private double total;        public ClassRoom()    {        stuList = new ArrayList
      
       ();    }    public ClassRoom(String no)    {        this();        this.no = no;    }        public ClassRoom(String no, List
       
         stuList, double total)    {        super();        this.no = no;        this.stuList = stuList;        this.total = total;    }    public String getNo()    {        return no;    }    public void setNo(String no)    {        this.no = no;    }    public List
        
          getStuList()    {        return stuList;    }    public void setStuList(List
         
           stuList)    {        this.stuList = stuList;    }    public double getTotal()    {        return total;    }    public void setTotal(double total)    {        this.total = total;    }        }

MapDemo03.java

package yzhou.map;import java.util.ArrayList;import java.util.HashMap;import java.util.Iterator;import java.util.List;import java.util.Map;import java.util.Set;/** *  * 面向对象+分解存储 * @author 洋 * */public class MapDemo03{    public static void main(String[] args)    {        List
     
       stuList = exam();        Map
      
        map = count(stuList);        view(map);    }        /*     * 查看每个班的总分和平均分    --》遍历map     * */    public static void view(Map
       
         map)    {        Set
        
          keys = map.keySet();        //获取迭代器对象        Iterator
         
           keysIt = keys.iterator();        //先判断        while(keysIt.hasNext()){            //在获取            String no = keysIt.next();            ClassRoom room = map.get(no);            //查看总分 计算平均分            double total = room.getTotal();            double avg = total/room.getStuList().size();            System.out.println(no+"--->"+total+"-->"+avg);        }            }        /*     * 统计分析     * */    public static Map
          
            count(List
           
             list){ Map
            
              map = new HashMap
             
              (); //1.遍历 for(Student stu:list) { //分拣查看是否存在， 该编号的班级 String no = stu.getNo(); double score = stu.getScore(); //如果不存在 ，创建班级 ClassRoom room = map.get(no); if(null==room) { room = new ClassRoom(no); map.put(no, room); } //存在，放入学生 room.getStuList().add(stu); room.setTotal(room.getTotal()+score); } return map; } /* * 模拟考试 测试数据到List 中 * */ public static List
              
                exam(){ List
               
                 list = new ArrayList
                
                 (); //存放学生成绩 list.add(new Student("yzhou01","a",80)); list.add(new Student("yzhou02","a",80)); list.add(new Student("yzhou03","a",80)); list.add(new Student("yzhou04","b",80)); list.add(new Student("yzhou05","b",80)); list.add(new Student("yzhou06","b",80)); return list; }; }