Question

所以我在这里创建了一个代码，它创建了一个名为student的对象，它接受名称和专业的字符串，并跟踪总积分和质量点来计算GPA。我正在尝试创建一个HashMap，以便能够使用密钥（学生ID）搜索学生并获取使用Student蓝图类保存的值。但我的代码是为所有键分配相同的值，最后一个学生进入HashMap。这是当前输出后面的代码。请注意，这是我完整代码的简化版本，只是为了展示我遇到的问题。感谢愿意提供帮助的任何人！

import java.util.HashMap;

public class Test {
public static class Student {
    static private String name;
    static private String major;
    static private int totalCredits;
    static private int totalQP;

    public Student (String name, String major) {
        this.name = name;
        this.major = major;
        this.totalCredits = 0;
        this.totalQP = 0;
    }

    public static void courseCompleted (int grade, int creditHours) {
        totalQP += grade;
        totalCredits += creditHours;
    }

    @Override
    public String toString () {
        float GPA;
        if (totalCredits != 0) {
            GPA = (float) totalQP/totalCredits;
        } else {
            GPA = (float) 4.0;
        }
        return "Student name: " + name + "\nStudent Major: " + major
                + "\nStudent GPA: " + GPA;
    }
}

public static void main (String [] args) {
    HashMap<Integer, Student> studentDatabase = new HashMap();

    studentDatabase.put(1234, new Student("Default", "Default"));
    studentDatabase.put(7623, new Student("Phyllis Jones", "English"));
    studentDatabase.put(8729, new Student("Cletus Smith", "History"));
    studentDatabase.put(7321, new Student("Betty Booth", "Computer Science"));
    studentDatabase.put(3242, new Student("Samuel Seybright", "History"));
    studentDatabase.put(9823, new Student("Oscar Blue", "English"));
    studentDatabase.put(2341, new Student("Sally Grief", "Copmputer Science"));
    studentDatabase.put(8321, new Student("Jacques Matchel", "Mathematics"));

    System.out.println(studentDatabase.entrySet());
}
}

输出： [8321 =学生姓名：Jacques Matchel 学生专业：数学学生GPA：4.0,1234 =学生姓名：Jacques Matchel 学生专业：数学学生GPA：4.0,2341 =学生姓名：Jacques Matchel 学生专业：数学学生GPA：4.0,7623 =学生姓名：Jacques Matchel 学生专业：数学学生GPA：4.0,8729 =学生姓名：Jacques Matchel 学生专业：数学学生GPA：4.0,7321 =学生姓名：Jacques Matchel 学生专业：数学学生GPA：4.0,3242 =学生姓名：Jacques Matchel 学生专业：数学学生GPA：4.0,9823 =学生姓名：Jacques Matchel 学生专业：数学学生GPA：4.0]

HashMap <integer，object =“”>为所有键分配相同的值

0 个答案: