# JavaClassroomTest1

**Repository Path**: cjhsyc/java-classroom-test1

## Basic Information

- **Project Name**: JavaClassroomTest1
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 1
- **Forks**: 0
- **Created**: 2021-11-25
- **Last Updated**: 2021-11-27

## Categories & Tags

**Categories**: Uncategorized

**Tags**: Java

## README

### 一、自定义文件，存放某班级学生期末各科考试原始成绩
1、创建实体类（StudentScore）

```
package entity;

import java.io.Serializable;

public class StudentScore implements Serializable,Comparable<StudentScore> {
    private Integer studentID;
    private Integer java;//java成绩
    private Integer math;//数学成绩

    public StudentScore(Integer studentID, Integer java, Integer math) {
        this.studentID = studentID;
        this.java = java;
        this.math = math;
    }

    public Integer getStudentID() {
        return studentID;
    }

    public void setStudentID(Integer studentID) {
        this.studentID = studentID;
    }

    public Integer getJava() {
        return java;
    }

    public void setJava(Integer java) {
        this.java = java;
    }

    public Integer getMath() {
        return math;
    }

    public void setMath(Integer math) {
        this.math = math;
    }

    @Override
    public String toString() {
        return "studentScore{" +
                "studentID=" + studentID +
                ", java=" + java +
                ", math=" + math +
                '}';
    }

    @Override
    public int compareTo(StudentScore o) {//按java分数比较
        return this.java-o.java;
    }
}

```
2、采用对象输入输出流，写入文件

```
package test;

import entity.StudentScore;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.util.ArrayList;
import java.util.List;

public class Test1 {
    public static void main(String[] args) throws IOException {
        ObjectOutputStream obs=new ObjectOutputStream(new FileOutputStream("D:\\StudentScore.txt"));
        StudentScore s1=new StudentScore(1,90,55);
        StudentScore s2=new StudentScore(2,33,88);
        StudentScore s3=new StudentScore(3,67,48);
        StudentScore s4=new StudentScore(4,92,56);
        StudentScore s5=new StudentScore(5,78,88);
        List<StudentScore> list=new ArrayList<>();
        list.add(s1);
        list.add(s2);
        list.add(s3);
        list.add(s4);
        list.add(s5);
        obs.writeObject(list);//写入文件
        obs.flush();
        obs.close();
    }
}
```

3、生成文件（StudentScore.txt），已和源代码一起上传

### 二、读取上述原始成绩文件，按照某门课程分数高低排序
1、代码如下

```
package test;

import entity.StudentScore;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.util.Collections;
import java.util.List;

public class Test2 {
    public static void main(String[] args) throws IOException, ClassNotFoundException {
        List<StudentScore> list=readAndSort();
        for(StudentScore s:list){
            System.out.println(s);
        }
    }

    public static List<StudentScore> readAndSort() throws IOException, ClassNotFoundException {
        ObjectInputStream ois=new ObjectInputStream(new FileInputStream("D:\\StudentScore.txt"));
        List<StudentScore> list=(List<StudentScore>) ois.readObject();//读取文件
        ois.close();
        Collections.sort(list);//按java分数从小到大排序
        return list;
    }
}

```
2、运行结果如下（按java成绩从小到大排序）
![输入图片说明](https://images.gitee.com/uploads/images/2021/1125/154137_2b7ff117_9634894.png "屏幕截图.png")

### 三、输出排序后的新文件,并在屏幕显示某门课挂科详情。
1、代码如下

```
package test;

import entity.StudentScore;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.util.List;

public class Test3 {
    public static void main(String[] args) throws IOException, ClassNotFoundException {
        List<StudentScore> list= Test2.readAndSort();
        ObjectOutputStream obs=new ObjectOutputStream(new FileOutputStream("D:\\NewStudentScore.txt"));
        obs.writeObject(list);//写入文件
        obs.flush();
        obs.close();
        System.out.println("java挂科详情：");
        for(StudentScore s:list){
            if(s.getJava()<60){
                System.out.println(s);
            }
        }
        System.out.println("数学挂科详情：");
        for(StudentScore s:list){
            if(s.getMath()<60){
                System.out.println(s);
            }
        }
    }
}
```
2、生成文件（NewStudentScore.txt）已和源代码一起上传

3、运行结果如下（各科挂科信息）
![输入图片说明](https://images.gitee.com/uploads/images/2021/1125/154231_c61c2099_9634894.png "屏幕截图.png")