import java.util.HashMap; import java.util.Map; import java.util.Scanner; class GradeQuerySystem { private Map gradeBook; public GradeQuerySystem() { gradeBook = new HashMap(); } public void addStudentGrade(String studentName, int grade) { gradeBook.put(studentName, grade); } public int getStudentGrade(String studentName) { if (gradeBook.containsKey(studentName)) { return gradeBook.get(studentName); } else { return -1; // 表示找不到该学生的成绩 } } } public class Main { public static void main(String[] args) { GradeQuerySystem system = new GradeQuerySystem(); system.addStudentGrade("Alice", 85); system.addStudentGrade("Bob", 92); system.addStudentGrade("Charlie", 78); system.addStudentGrade("David", 95); system.addStudentGrade("Eve", 88); Scanner scanner = new Scanner(System.in); System.out.print("请输入学生姓名:"); String studentName = scanner.nextLine(); int grade = system.getStudentGrade(studentName); if (grade != -1) { System.out.println(studentName + "的成绩为:" + grade); } else { System.out.println("找不到该学生的成绩!"); } } } 学生成绩查询系统是现代教育管理中不可或缺的一部分。通过使用学生成绩查询系统,老师可以方便地管理和查询学生的学业成绩,为学生提供个性化的学术指导。