【java编程】IO流和集合类综合题目

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需求：

1.有5个学生，每个学生有三门功课

2.从键盘输入以上数据(姓名，三门课成绩)

3.输入格式为：zhangshan，30，40，60并计算出总成绩

4.把学生信息和计算出来的总成绩按从低到高的顺序进行存储

思路：

1.先创建一个学生对象，实现比较器，让学生对象自身具备比较性，同时要复写hashcode()和equeas()方法

2.创建键盘录入，同时创建TreeSet集合，将键盘录入的数据存入集合

3.将集合中的数据存入到文件中

import java.io.*;import java.util.*;class  StudentInfoTest{public static void main(String[] args) throws IOException{//自定义比较器Comparator<Student> cmp=Collections.reverseOrder();Set<Student> treeset=StudentInfoTool.getStudentInfo(cmp);StudentInfoTool.writeToFile(treeset);}}//创建学生对象class Student implements Comparable<Student>{private String name;private int cn;private int ma;private int en;private int sum;Student(String name,int cn,int ma,int en){this.name=name;this.cn=cn;this.ma=ma;this.en=en;sum=cn+ma+en;}public String getName(){return name;}public int getSum(){return sum;}//复写hashCode方法public int hashCode(){return this.name.hashCode()+sum*6;}//复写equals方法public boolean equals(Object obj){if(obj instanceof Student)throw new ClassCastException("类型不匹配！");Student str=(Student)obj;return this.name.equals(str.getName()) && this.sum==str.getSum();}public int compareTo(Student s){int num=new Integer(this.sum).compareTo(new Integer(s.sum));if(num==0)return this.name.compareTo(s.name);return num;}public String toString(){return "["+name+", "+cn+", "+ma+", "+en+"]";}}//创建操作学生的工具类class StudentInfoTool{//空比较器public static Set<Student> getStudentInfo() throws IOException{return StudentInfoTool.getStudentInfo(null);}public static Set<Student> getStudentInfo(Comparator<Student> cmp) throws IOException{//键盘录入BufferedReader bufr=new BufferedReader(new InputStreamReader(System.in));//创建TreeSet集合,cmp为自定义比较器Set<Student> treeset=new TreeSet<Student>(cmp);String line=null;while((line=bufr.readLine())!=null){if("over".equals(line))break;//通过","对学生信息进行切割String[] info=line.split(",");Student stu=new Student(info[0],Integer.parseInt(info[1]),Integer.parseInt(info[2]),Integer.parseInt(info[3]));treeset.add(stu);}bufr.close();System.out.println(treeset);return treeset;}//存入文件方法public static void writeToFile(Set<Student> stu) throws IOException{//文件写入流BufferedWriter bufw=new BufferedWriter(new FileWriter("studentInfo.txt"));//从集合里取出学生信息for(Student s : stu){bufw.write(s.toString()+"\t");bufw.write(s.getSum()+"");bufw.newLine();bufw.flush();}bufw.close();}}

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