java难题，希望各位能解决
请各位朋友解决下这个问题，这个学生成绩管理系统由成绩的录入，成绩的查询，成绩的统计组成，成绩为语文成绩，数学成绩，英语成绩
这不算难题，就是你们一个课程的练习题。
import java.util.*;
class Student {
private int id;
private String name;
private int chineseScore;
private int mathScore;
private int englishScore;
public Student(int id, String name, int chineseScore, int mathScore, int englishScore) {
this.id = id;
this.name = name;
this.chineseScore = chineseScore;
this.mathScore = mathScore;
this.englishScore = englishScore;
}
public int getId() {
return id;
}
public String getName() {
return name;
}
public int getChineseScore() {
return chineseScore;
}
public int getMathScore() {
return mathScore;
}
public int getEnglishScore() {
return englishScore;
}
public int getTotalScore() {
return chineseScore + mathScore + englishScore;
}
public double getAverageScore() {
return getTotalScore() / 3.0;
}
}
class StudentManager {
private List<Student> students;
private Map<Integer, Student> idToStudentMap;
private Map<String, List<Student>> nameToStudentListMap;
public StudentManager() {
students = new ArrayList<>();
idToStudentMap = new HashMap<>();
nameToStudentListMap = new HashMap<>();
}
public void addStudent() {
Scanner scanner = new Scanner(System.in);
int id = 0;
String name = null;
int chineseScore = 0;
int mathScore = 0;
int englishScore = 0;
boolean validInput = false;
while (!validInput) {
System.out.print("请输入学生学号（1-90）：");
id = scanner.nextInt();
scanner.nextLine(); // consume the newline character
if (id < 1 || id > 90) {
System.out.println("学号不合法，请重新输入！");
} else if (idToStudentMap.containsKey(id)) {
System.out.println("学号已存在，请重新输入！");
} else {
validInput = true;
}
}
validInput = false;
while (!validInput) {
System.out.print("请输入学生姓名（只包含英文字母和空格）：");
name = scanner.nextLine();
if (!name.matches("[a-zA-Z ]+")) {
System.out.println("姓名不合法，请重新输入！");
} else {
validInput = true;
}
}
validInput = false;
while (!validInput) {
System.out.print("请输入语文成绩（0-100）：");
chineseScore = scanner.nextInt();
if (chineseScore < 0 || chineseScore > 100) {
System.out.println("成绩不合法，请重新输入！");
} else {
validInput = true;
}
}
validInput = false;
while (!validInput) {
System.out.print("请输入数学成绩（0-100）：");
mathScore = scanner.nextInt();
if (mathScore < 0 || mathScore > 100) {
System.out.println("成绩不合法，请重新输入！");
} else {
validInput = true;
}
}
validInput = false;
while (!validInput) {
System.out.print("请输入英语成绩（0-100）：");
englishScore = scanner.nextInt();
if (englishScore < 0 || englishScore > 100) {
System.out.println("成绩不合法，请重新输入！");
} else {
validInput = true;
}
}
Student student = new Student(id, name, chineseScore, mathScore, englishScore);
students.add(student);
idToStudentMap.put(id, student);
List<Student> studentList = nameToStudentListMap.get(name.toLowerCase());
if (studentList == null) {
studentList = new ArrayList<>();
nameToStudentListMap.put(name.toLowerCase(), studentList);
}
studentList.add(student);
System.out.println("学生信息录入成功！");
}
public void searchById() {
Scanner scanner = new Scanner(System.in);
System.out.print("请输入要查询的学生学号：");
int id = scanner.nextInt();
Student student = idToStudentMap.get(id);
if (student == null) {
System.out.println("找不到该学生！");
} else {
System.out.println("学号\t姓名\t语文\t数学\t英语\t总分\t平均分");
System.out.println(student.getId() + "\t" + student.getName() + "\t" +
student.getChineseScore() + "\t" + student.getMathScore() + "\t" +
student.getEnglishScore() + "\t" + student.getTotalScore() + "\t" +
String.format("%.2f", student.getAverageScore()));
}
}
public void searchByName() {
Scanner scanner = new Scanner(System.in);
System.out.print("请输入要查询的学生姓名：");
String name = scanner.nextLine().toLowerCase();
List<Student> studentList = nameToStudentListMap.get(name);
if (studentList == null) {
System.out.println("找不到该学生！");
} else {
System.out.println("学号\t姓名\t语文\t数学\t英语\t总分\t平均分");
for (Student student : studentList) {
System.out.println(student.getId() + "\t" + student.getName() + "\t" +
student.getChineseScore() + "\t" + student.getMathScore() + "\t" +
student.getEnglishScore() + "\t" + student.getTotalScore() + "\t" +
String.format("%.2f", student.getAverageScore()));
}
}
}
public void showStatistics() {
int chineseFailCount = 0;
int mathFailCount = 0;
int englishFailCount = 0;
int chineseTotalScore = 0;
int mathTotalScore = 0;
int englishTotalScore = 0;
int chineseMaxScore = 0;
int mathMaxScore = 0;
int englishMaxScore = 0;
int chineseMinScore = 100;
int mathMinScore = 100;
int englishMinScore = 100;
List<Student> studentsCopy = new ArrayList<>(students);
Collections.sort(studentsCopy, new Comparator<Student>() {
public int compare(Student s1, Student s2) {
return s2.getTotalScore() - s1.getTotalScore();
}
});
System.out.println("各科成绩不及格人数和比例：");
for (Student student : students) {
if (student.getChineseScore() < 60) {
chineseFailCount++;
}
if (student.getMathScore() < 60) {
mathFailCount++;
}
if (student.getEnglishScore() < 60) {
englishFailCount++;
}
}
System.out.println("语文：不及格人数=" + chineseFailCount + "，比例=" +
String.format("%.2f", chineseFailCount / (double) students.size()));
System.out.println("数学：不及格人数=" + mathFailCount + "，比例=" +
String.format("%.2f", mathFailCount / (double) students.size()));
System.out.println("英语：不及格人数=" + englishFailCount + "，比例=" +
String.format("%.2f", englishFailCount / (double) students.size()));
System.out.println("各科平均分：");
for (Student student : students) {
chineseTotalScore += student.getChineseScore();
mathTotalScore += student.getMathScore();
englishTotalScore += student.getEnglishScore();
if (student.getChineseScore() > chineseMaxScore) {
chineseMaxScore = student.getChineseScore();
}
if (student.getMathScore() > mathMaxScore) {
mathMaxScore = student.getMathScore();
}
if (student.getEnglishScore() > englishMaxScore) {
englishMaxScore = student.getEnglishScore();
}
if (student.getChineseScore() < chineseMinScore) {
chineseMinScore = student.getChineseScore();
}
if (student.getMathScore() < mathMinScore) {
mathMinScore = student.getMathScore();
}
if (student.getEnglishScore() < englishMinScore) {
englishMinScore = student.getEnglishScore();
}
}
System.out.println("语文平均分=" + chineseTotalScore / (double) students.size());
System.out.println("数学平均分=" + mathTotalScore / (double) students.size());
System.out.println("英语平均分=" + englishTotalScore / (double) students.size());
System.out.println("各科最高分和最低分：");
System.out.println("语文最高分=" + chineseMaxScore + "，最低分=" + chineseMinScore);
System.out.println("数学最高分=" + mathMaxScore + "，最低分=" + mathMinScore);
System.out.println("英语最高分=" + englishMaxScore + "，最低分=" + englishMinScore);
System.out.println("各科成绩排名：");
System.out.println("排名\t学号\t姓名\t语文\t数学\t英语\t总分\t平均分");
for (int i = 0; i < studentsCopy.size(); i++) {
Student student = studentsCopy.get(i);
System.out.println((i + 1) + "\t" + student.getId() + "\t" + student.getName() + "\t" +
student.getChineseScore() + "\t" + student.getMathScore() + "\t" +
student.getEnglishScore() + "\t" + student.getTotalScore() + "\t" +
String.format("%.2f", student.getAverageScore()));
}
}
}
public class Main {
public static void main(String[] args) {
StudentManager studentManager = new StudentManager();
Scanner scanner = new Scanner(System.in);
while (true) {
System.out.println("请选择要进行的操作：");
System.out.println("1. 录入学生成绩");
System.out.println("2. 按学号查询学生成绩");
System.out.println("3. 按姓名查询学生成绩");
System.out.println("4. 显示成绩统计信息");
System.out.println("5. 退出程序");
System.out.print("请输入操作编号：");
int choice = scanner.nextInt();
scanner.nextLine(); // consume the newline character
switch (choice) {
case 1:
studentManager.addStudent();
break;
case 2:
studentManager.searchById();
break;
case 3:
studentManager.searchByName();
break;
case 4:
studentManager.showStatistics();
break;
case 5:
System.out.println("程序已退出！");
System.exit(0);
default:
System.out.println("无效的操作编号，请重新输入！");
}
System.out.println();
}
}
}
1 建表 包含字段在要求1中
2 创建项目 实体 controller service impl dao
3 前端支持layui有现成模板 套一份
4 对接调试 完成
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Scanner;
class Student {
private int id;
private String name;
private int chineseScore;
private int mathScore;
private int englishScore;
public Student(int id, String name, int chineseScore, int mathScore, int englishScore) {
this.id = id;
this.name = name;
this.chineseScore = chineseScore;
this.mathScore = mathScore;
this.englishScore = englishScore;
}
// Getters and setters
public int getId() {
return id;
}
public String getName() {
return name;
}
public int getChineseScore() {
return chineseScore;
}
public int getMathScore() {
return mathScore;
}
public int getEnglishScore() {
return englishScore;
}
}
class ScoreManagementSystem {
private List<Student> students;
public ScoreManagementSystem() {
students = new ArrayList<>();
}
public void addStudent(Student student) {
students.add(student);
}
public void inputScores() {
Scanner scanner = new Scanner(System.in);
System.out.print("请输入学号：");
int id = scanner.nextInt();
System.out.print("请输入姓名：");
scanner.nextLine();
String name = scanner.nextLine();
System.out.print("请输入语文成绩：");
int chineseScore = scanner.nextInt();
System.out.print("请输入数学成绩：");
int mathScore = scanner.nextInt();
System.out.print("请输入英语成绩：");
int englishScore = scanner.nextInt();
// 验证数据有效性
if (id < 1 || id > 90 || chineseScore < 0 || chineseScore > 100 ||
mathScore < 0 || mathScore > 100 || englishScore < 0 || englishScore > 100) {
System.out.println("数据无效，无法录入成绩！");
return;
}
Student student = new Student(id, name, chineseScore, mathScore, englishScore);
addStudent(student);
System.out.println("成绩录入成功！");
}
public void queryByStudentId(int id) {
List<Student> results = new ArrayList<>();
for (Student student : students) {
if (student.getId() == id) {
results.add(student);
}
}
if (results.isEmpty()) {
System.out.println("未找到该学生的成绩记录！");
return;
}
System.out.println("查询结果：");
for (Student student : results) {
System.out.println("学号：" + student.getId() +
"，姓名：" + student.getName() +
"，语文成绩：" + student.getChineseScore() +
"，数学成绩：" + student.getMathScore() +
"，英语成绩：" + student.getEnglishScore());
}
}
public void queryByStudentName(String name) {
List<Student> results = new ArrayList<>();
for (Student student : students) {
if (student.getName().equalsIgnoreCase(name)) {
results.add(student);
}
}
if (results.isEmpty()) {
System.out.println("未找到该学生的成绩记录！");
return;
}
System.out.println("查询结果：");
for (Student student : results) {
System.out.println("学号：" + student.getId() +
"，姓名：" + student.getName() +
"，语文成绩：" + student.getChineseScore() +
"，数学成绩：" + student.getMathScore() +
"，英语成绩：" + student.getEnglishScore());
}
}
public void queryFailedSubjects() {
List<Student> results = new ArrayList<>();
for (Student student : students) {
if (student.getChineseScore() < 60) {
results.add(student);
}
if (student.getMathScore() < 60) {
results.add(student);
}
if (student.getEnglishScore() < 60) {
results.add(student);
}
}
if (results.isEmpty()) {
System.out.println("未找到不及格的科目！");
return;
}
System.out.println("不及格的科目：");
for (Student student : results) {
System.out.println("学号：" + student.getId() +
"，姓名：" + student.getName());
}
}
public void calculateAverageScores() {
double chineseTotal = 0;
double mathTotal = 0;
double englishTotal = 0;
for (Student student : students) {
chineseTotal += student.getChineseScore();
mathTotal += student.getMathScore();
englishTotal += student.getEnglishScore();
}
double chineseAverage = chineseTotal / students.size();
double mathAverage = mathTotal / students.size();
double englishAverage = englishTotal / students.size();
System.out.println("各门课的平均分：");
System.out.println("语文平均分：" + chineseAverage);
System.out.println("数学平均分：" + mathAverage);
System.out.println("英语平均分：" + englishAverage);
}
public void rankScores() {
List<Student> chineseScores = new ArrayList<>(students);
List<Student> mathScores = new ArrayList<>(students);
List<Student> englishScores = new ArrayList<>(students);
Comparator<Student> scoreComparator = Comparator.comparingInt(Student::getChineseScore);
chineseScores.sort(scoreComparator.reversed());
scoreComparator = Comparator.comparingInt(Student::getMathScore);
mathScores.sort(scoreComparator.reversed());
scoreComparator = Comparator.comparingInt(Student::getEnglishScore);
englishScores.sort(scoreComparator.reversed());
System.out.println("语文成绩排名：");
for (int i = 0; i < chineseScores.size(); i++) {
Student student = chineseScores.get(i);
System.out.println("排名第 " + (i + 1) +
" 的学生：学号：" + student.getId() +
"，姓名：" + student.getName() +
"，成绩：" + student.getChineseScore());
}
System.out.println("数学成绩排名：");
for (int i = 0; i < mathScores.size(); i++) {
Student student = mathScores.get(i);
System.out.println("排名第 " + (i + 1) +
" 的学生：学号：" + student.getId() +
"，姓名：" + student.getName() +
"，成绩：" + student.getMathScore());
}
System.out.println("英语成绩排名：");
for (int i = 0; i < englishScores.size(); i++) {
Student student = englishScores.get(i);
System.out.println("排名第 " + (i + 1) +
" 的学生：学号：" + student.getId() +
"，姓名：" + student.getName() +
"，成绩：" + student.getEnglishScore());
}
}
public void calculateGradeDistribution() {
int below60 = 0;
int from60to70 = 0;
int from70to80 = 0;
int from80to90 = 0;
int above90 = 0;
for (Student student : students) {
int totalScore = student.getChineseScore() + student.getMathScore() + student.getEnglishScore();
if (totalScore < 60) {
below60++;
} else if (totalScore < 70) {
from60to70++;
} else if (totalScore < 80) {
from70to80++;
} else if (totalScore < 90) {
from80to90++;
} else {
above90++;
}
}
System.out.println("各成绩区段的人数比例：");
System.out.println("60分以下：" + (double) below60 / students.size());
System.out.println("60分-70分：" + (double) from60to70 / students.size());
System.out.println("70分-80分：" + (double) from70to80 / students.size());
System.out.println("80分-90分：" + (double) from80to90 / students.size());
System.out.println("90分以上：" + (double) above90 / students.size());
}
}
public class Main {
public static void main(String[] args) {
ScoreManagementSystem system = new ScoreManagementSystem();
Scanner scanner = new Scanner(System.in);
while (true) {
System.out.println("------- 学生成绩管理系统 -------");
System.out.println("1. 成绩录入");
System.out.println("2. 成绩查询");
System.out.println("3. 成绩统计");
System.out.println("0. 退出系统");
System.out.print("请选择操作：");
int choice = scanner.nextInt();
switch (choice) {
case 1:
system.inputScores();
break;
case 2:
System.out.println("------- 成绩查询 -------");
System.out.println("1. 按学号查询");
System.out.println("2. 按姓名查询");
System.out.print("请选择查询方式：");
int queryChoice = scanner.nextInt();
switch (queryChoice) {
case 1:
System.out.print("请输入学号：");
int id = scanner.nextInt();
system.queryByStudentId(id);
break;
case 2:
System.out.print("请输入姓名：");
scanner.nextLine();
String name = scanner.nextLine();
system.queryByStudentName(name);
break;
default:
System.out.println("无效的选择！");
break;
}
break;
case 3:
System.out.println("------- 成绩统计 -------");
System.out.println("1. 统计各门课的不及格人数及比例");
System.out.println("2. 统计各门课的平均分");
System.out.println("3. 按从最高分到最低分对各门课成绩进行排名");
System.out.println("4. 统计各成绩区段的人数比例");
System.out.print("请选择统计方式：");
int statChoice = scanner.nextInt();
switch (statChoice) {
case 1:
system.queryFailedSubjects();
break;
case 2:
system.calculateAverageScores();
break;
case 3:
system.rankScores();
break;
case 4:
system.calculateGradeDistribution();
break;
default:
System.out.println("无效的选择！");
break;
}
break;
case 0:
System.out.println("已退出学生成绩管理系统！");
System.exit(0);
default:
System.out.println("无效的选择！");
break;
}
}
}
}
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import java.util.Scanner;
class Student {
private int id;
private String name;
private int chineseScore;
private int mathScore;
private int englishScore;
public Student(int id, String name, int chineseScore, int mathScore, int englishScore) {
this.id = id;
this.name = name;
this.chineseScore = chineseScore;
this.mathScore = mathScore;
this.englishScore = englishScore;
}
public int getId() {
return id;
}
public String getName() {
return name;
}
public int getChineseScore() {
return chineseScore;
}
public int getMathScore() {
return mathScore;
}
public int getEnglishScore() {
return englishScore;
}
}
class ScoreManagementSystem {
private List<Student> students;
public ScoreManagementSystem() {
students = new ArrayList<>();
}
public void addStudent(Student student) {
students.add(student);
}
public List<Student> searchById(int id) {
List<Student> result = new ArrayList<>();
for (Student student : students) {
if (student.getId() == id) {
result.add(student);
}
}
return result;
}
public List<Student> searchByName(String name) {
List<Student> result = new ArrayList<>();
for (Student student : students) {
if (student.getName().equalsIgnoreCase(name)) {
result.add(student);
}
}
return result;
}
public List<Student> searchByPartialName(String partialName) {
List<Student> result = new ArrayList<>();
for (Student student : students) {
if (student.getName().toLowerCase().contains(partialName.toLowerCase())) {
result.add(student);
}
}
return result;
}
public void displayScores(List<Student> studentList) {
for (Student student : studentList) {
System.out.println("Student ID: " + student.getId());
System.out.println("Student Name: " + student.getName());
System.out.println("Chinese Score: " + student.getChineseScore());
System.out.println("Math Score: " + student.getMathScore());
System.out.println("English Score: " + student.getEnglishScore());
System.out.println();
}
}
public void displayFailedSubjects(List<Student> studentList) {
for (Student student : studentList) {
System.out.println("Student ID: " + student.getId());
System.out.println("Student Name: " + student.getName());
if (student.getChineseScore() < 60) {
System.out.println("Failed in Chinese");
}
if (student.getMathScore() < 60) {
System.out.println("Failed in Math");
}
if (student.getEnglishScore() < 60) {
System.out.println("Failed in English");
}
System.out.println();
}
}
public void displayScoreRankings() {
students.sort(Comparator.comparingInt(Student::getChineseScore).reversed());
System.out.println("Chinese Score Rankings:");
displayRankings(students);
students.sort(Comparator.comparingInt(Student::getMathScore).reversed());
System.out.println("Math Score Rankings:");
displayRankings(students);
students.sort(Comparator.comparingInt(Student::getEnglishScore).reversed());
System.out.println("English Score Rankings:");
displayRankings(students);
}
private void displayRankings(List<Student> studentList) {
int rank = 1;
for (Student student : studentList) {
System.out.println("Rank: " + rank);
System.out.println("Student ID: " + student.getId());
System.out.println("Student Name: " + student.getName());
System.out.println("Chinese Score: " + student.getChineseScore());
System.out.println("Math Score: " + student.getMathScore());
System.out.println("English Score: " + student.getEnglishScore());
System.out.println();
rank++;
}
}
public void displayScoreStatistics() {
int chineseFailedCount = 0;
int mathFailedCount = 0;
int englishFailedCount = 0;
double chineseAverage = 0.0;
double mathAverage = 0.0;
double englishAverage = 0.0;
int totalStudents = students.size();
for (Student student : students) {
if (student.getChineseScore() < 60) {
chineseFailedCount++;
}
if (student.getMathScore() < 60) {
mathFailedCount++;
}
if (student.getEnglishScore() < 60) {
englishFailedCount++;
}
chineseAverage += student.getChineseScore();
mathAverage += student.getMathScore();
englishAverage += student.getEnglishScore();
}
chineseAverage /= totalStudents;
mathAverage /= totalStudents;
englishAverage /= totalStudents;
System.out.println("Chinese Failed Count: " + chineseFailedCount);
System.out.println("Chinese Failed Ratio: " + (double)chineseFailedCount / totalStudents);
System.out.println("Math Failed Count: " + mathFailedCount);
System.out.println("Math Failed Ratio: " + (double)mathFailedCount / totalStudents);
System.out.println("English Failed Count: " + englishFailedCount);
System.out.println("English Failed Ratio: " + (double)englishFailedCount / totalStudents);
System.out.println("Chinese Average Score: " + chineseAverage);
System.out.println("Math Average Score: " + mathAverage);
System.out.println("English Average Score: " + englishAverage);
}
}
public class Main {
public static void main(String[] args) {
ScoreManagementSystem scoreSystem = new ScoreManagementSystem();
// 添加学生及成绩信息
scoreSystem.addStudent(new Student(1, "Alice", 90, 85, 95));
scoreSystem.addStudent(new Student(2, "Bob", 80, 75, 85));
scoreSystem.addStudent(new Student(3, "Charlie", 70, 65, 75));
scoreSystem.addStudent(new Student(4, "David", 60, 55, 65));
// 演示成绩查询功能
List<Student> resultById = scoreSystem.searchById(2);
scoreSystem.displayScores(resultById);
List<Student> resultByName = scoreSystem.searchByName("Alice");
scoreSystem.displayScores(resultByName);
List<Student> resultByPartialName = scoreSystem.searchByPartialName("a");
scoreSystem.displayScores(resultByPartialName);
// 演示成绩统计功能
scoreSystem.displayFailedSubjects(scoreSystem.searchByPartialName("a"));
scoreSystem.displayScoreRankings();
scoreSystem.displayScoreStatistics();
}
}
- 这个问题的回答你可以参考下: https://ask.csdn.net/questions/7517564
- 我还给你找了一篇非常好的博客，你可以看看是否有帮助，链接：【JAVA笔记】习题：尝试编写一个矩形类，将长与宽作为矩形类的属性，在构造方法中将长，宽初始化，定义一个成员方法求此矩形的面积。
- 你还可以看下java参考手册中的 java-学习Java语言 - 描述Java编程语言的基本概念和特点的课程。-泛型是Java编程语言的一个强大功能。它们提高了代码的类型安全性，使更多的错误可以在编译时发现。-野生动物
- 除此之外, 这篇博客: java反射，反射常用方法，获取类模板，通过类模板对象创建实体对象，类中未定义有参或无参构造器的情况下创建对象，不调用方法尝试给一个类的私有属性赋值，通过反射获取一个类的父类并获取它实现的接口中的 java反射 部分也许能够解决你的问题, 你可以仔细阅读以下内容或跳转源博客中阅读:
Reflection（反射）是被视为动态语言的关键，反射机制允许程序在执行期（运行时）借助于Reflection API取得任何类的内部信息，并能直接操作任意对象的内部属性及方法
- 您还可以看一下 徐无忌老师的Java进阶高手课-并发编程透彻理解课程中的 什么是多线程的上下文切换，有什么影响？如何进行优化？（一）小节, 巩固相关知识点
- 以下回答由chatgpt基于相关博客总结生成:
针对学生成绩管理系统，我会给出以下解决方案：
定义一个学生类Student 具有属性：姓名name、语文成绩chinese、数学成绩math、英语成绩english 具有方法：get和set方法
定义一个成绩管理类ScoreManager 具有属性：studentList(ArrayList) 具有方法： （1）addScore(添加学生成绩) 接收参数：Student对象 将该学生添加到studentList中 （2）searchScore(查询学生成绩) 接收参数：需要查询的科目（比如"语文"） 遍历studentList，找到所有学生在该科目上的成绩，返回成绩列表 （3）statistics(统计学生成绩) 接收参数：需要统计的科目（比如"英语"） 遍历studentList，计算所有学生在该科目上的总成绩，返回总分和平均分
在main方法中，实例化ScoreManager类，并调用各个方法实现相应功能。
下面是Java代码实现：
public class Student { private String name; private int chinese; private int math; private int english; // 构造方法 public Student(String n, int c, int m, int e) { name = n; chinese = c; math = m; english = e; } // get和set方法 public String getName() { return name; } public void setName(String name) { this.name = name; } public int getChinese() { return chinese; } public void setChinese(int chinese) { this.chinese = chinese; } public int getMath() { return math; } public void setMath(int math) { this.math = math; } public int getEnglish() { return english; } public void setEnglish(int english) { this.english = english; } } import java.util.ArrayList; public class ScoreManager { private ArrayList<Student> studentList = new ArrayList<Student>(); // 添加学生成绩 public void addScore(Student s) { studentList.add(s); } // 查询学生成绩 public ArrayList<Integer> searchScore(String subject) { ArrayList<Integer> scoreList = new ArrayList<Integer>(); for (Student s : studentList) { if (subject.equals("语文")) { scoreList.add(s.getChinese()); } else if (subject.equals("数学")) { scoreList.add(s.getMath()); } else if (subject.equals("英语")) { scoreList.add(s.getEnglish()); } } return scoreList; } // 统计学生成绩 public String statistics(String subject) { int sum = 0; if (subject.equals("语文")) { for (Student s : studentList) { sum += s.getChinese(); } } else if (subject.equals("数学")) { for (Student s : studentList) { sum += s.getMath(); } } else if (subject.equals("英语")) { for (Student s : studentList) { sum += s.getEnglish(); } } double avg = (double)sum / studentList.size(); return "总分为" + sum + "，平均分为" + String.format("%.2f", avg); } } import java.util.ArrayList; public class Main { public static void main(String[] args) { Student s1 = new Student("Tom", 80, 90, 70); Student s2 = new Student("Jerry", 90, 70, 80); Student s3 = new Student("Jack", 70, 80, 90); ScoreManager sm = new ScoreManager(); sm.addScore(s1); sm.addScore(s2); sm.addScore(s3); ArrayList<Integer> scoreList = sm.searchScore("语文"); System.out.println("语文成绩列表：" + scoreList.toString()); String result = sm.statistics("数学"); System.out.println("数学成绩统计：" + result); } }