哈希code到位数组元素的印 [英] Hash code printed in place of array elements

问题描述

我创建了一个新的类名为学生，设置和获取不同的变量，如姓名，GPA，如果他们入选，他们注册的时候（这是一个字符串，它的目的是）的程序。问题是，当我尝试将信息存储到一个数组和/或数组列表并打印我得到的哈希值code打印的，而不是信息。该计划还没有完全完成，但我想首先解决哈希code问题。如果你能帮助我更AP preciate。谢谢你在前进！

 学生ST =新学生（）;
    的System.out.println（st.getName（））;
    Student1（）;
    学生ST1 =新的学生（约翰）;}公共静态无效Student1（）{    的System.out.println（学生1输入数据：）;
    学生ST =新学生（）;
    扫描仪键盘=新的扫描仪（System.in）;    字符串名称= keyboard.next（）;
    双GPA = keyboard.nextDouble（）;
    布尔招收= keyboard.nextBoolean（）;
    字符串日期= keyboard.next（）;
     的for（int i = 0;我小于5;我++）{
    学生newStudent =新学生（）;
    newStudent.setName（名）;
    newStudent.setGPA（GPA）;
    newStudent.setEnrolled（登记）;
    newStudent.setDate（日期）;
    ArrayList的＆LT;的Student GT; strList =新的ArrayList＆LT;的Student GT;（）;
    学生学生[] =新的学生[5];
    newStudent.getName（）;
    学生[i] = newStudent;    strList.add（newStudent）;
    的System.out.println（学生[I]）;
 

}

学生班级

公共类学生{

 私人字符串名称;
私人双GPA;
私人布尔录取;
私人字符串enrollDate;公益助学（）{    this.name =;
    this.gpa = 0.0;
    this.enrolled = FALSE;
    this.enrollDate =无;}公益助学（字符串名称1）{
    this.name =名称1;
    this.gpa = 0.0;
    this.enrolled = FALSE;
    this.enrollDate =无;
}公共无效setname可以（字符串名称）{
    this.name =名称;
}公共字符串的getName（）{
    返回this.name;
}公共无效setGPA（双GPA）{
    this.gpa = GPA;
}公共双getGPA（）{
    返回this.gpa;
}公共无效setEnrolled（布尔就读）{
    this.enrolled =登记的;
}公共布尔getEnrolled（）{
    返回this.enrolled;
}公共无效的setDate（字符串日期）{
}
 

}

解决方案

1. 如果你想有一个重新的字符串对象的presentation，这个对象必须实现的toString（）。如果你没有在JVM中的默认设置是打印哈希code。


2. 如果您想打印对象的特定领域，你应该明确地打印领域，通过在必要的方法;像的System.out.println（学生[I] .getName（））;


3. 如果你想打印整个数组，你应该使用 Arrays.toString（）。

I created a program with a new class called Student that sets and gets different variables such as name, GPA, if they are enrolled and when they are enrolled (this is a String, it is intended to be). The problem is that when I try to store the information into an array and/or array list and print it I get the hash code printed instead of the information. The program is not entirely complete, but I am trying to address the hash code issue first. If you could assist I would much appreciate. Thank you in advance!

    Student st = new Student();


    System.out.println(st.getName());
    Student1();
    Student st1 = new Student("John");

}

public static void Student1() {

    System.out.println("Enter the data for student 1 :");
    Student st = new Student();
    Scanner keyboard = new Scanner(System.in);

    String name = keyboard.next();
    double GPA = keyboard.nextDouble();
    boolean enrolled = keyboard.nextBoolean();
    String date = keyboard.next();
     for (int i =0; i<5; i++){
    Student newStudent = new Student();
    newStudent.setName(name);
    newStudent.setGPA(GPA);
    newStudent.setEnrolled(enrolled);
    newStudent.setDate(date);
    ArrayList <Student> strList = new ArrayList<Student>();
    Student student[] = new Student[5];
    newStudent.getName();
    student[i] = newStudent;

    strList.add(newStudent);
    System.out.println(student[i]);

}

Student Class

public class Student {

private String name;
private double gpa;
private boolean enrolled;
private String enrollDate;

public Student() {

    this.name = "";
    this.gpa = 0.0;
    this.enrolled = false;
    this.enrollDate = "none";

}

public Student(String name1) {
    this.name = name1;
    this.gpa = 0.0;
    this.enrolled = false;
    this.enrollDate = "none";
}

public void setName(String name) {
    this.name = name;
}

public String getName() {
    return this.name;
}

public void setGPA(double gpa) {
    this.gpa = gpa;
}

public double getGPA() {
    return this.gpa;
}

public void setEnrolled(boolean enrolled) {
    this.enrolled = enrolled;


}

public boolean getEnrolled() {
    return this.enrolled;
}

public void setDate(String date) {
}

}

解决方案

1. If you want a String representation of an object, this object must implement toString(). If you don't the default in the JVM is to print the hash code.
2. If you want to print a specific field of your object, you should explicitly print that field, through a method if necessary; like System.out.println(student[i].getName());
3. If you are trying to print a whole array, you should use Arrays.toString().

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