用Java打印对象数组 [英] Printing an array of objects in Java
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问题描述
我正在制作电话簿并填写条目。这些条目包括两个姓氏和姓名字符串以及一个电话号码。我正在使用数组来存储条目。我正在尝试将数组打印出来，并且我在每个类中都添加了toString方法。但是当我打印出来时，我仍然得到[LEntry; @ 8dc8569。我不确定我做错了什么。这是代码。
public class Entry {
String surname;
String initial;
int number;
public Entry（String surname，String initial，int number）{
this.surname = surname;
this.initial = initial;
this.number = number;
}
public String getSurname（）{
return surname;
}
public String getInitial（）{
return initial;
}
public int getNumber（）{
返回数字;
}
void setNumber（int number）{
this.number = number;
}
public String toString（）{
return surname +\t+ initial +\t+ number;
}
}
公共类ArrayDirectory {
int DIRECTORY_SIZE = 6;
条目[]目录=新条目[DIRECTORY_SIZE];
public void addEntry（String surname，String initial，int num）{
int i = findFreeLocation（）;
目录[i] =新条目（姓氏，初始，数字）;
}
public void deleteEntry（String surname，String initial）{
int i = findEntryIndex（surname，initial）;
目录[i] = null;
}
public void deleteEntry（int number）{
int i = findEntryIndex（number）;
目录[i] = null;
}
public int findEntry（String surname，String initial）{
int i;
i = findEntryIndex（姓氏，初始）;
返回目录[i] .getNumber（）;
}
public void editNum（String surname，String initial，int number）{
int i;
i = findEntryIndex（姓氏，初始）;
目录[i] .setNumber（number）;
}
public void print（）{
// TODO print array
System.out.println（directory）;
}
private int findEntryIndex（String surname，String initial）{
int i;
for（i = 0; i< = DIRECTORY_SIZE; i ++）
{
if（directory [i]！= null&& directory [i] .getSurname（）。equals （姓）&& directory [i] .getInitial（）。equals（initial））
{
break;
}
}
返回i;
}
private int findEntryIndex（int number）{
int i;
for（i = 0; i< = DIRECTORY_SIZE; i ++）
{
if（directory [i]！= null&& directory [i] .getNumber（）==数字）
{
break;
}
}
返回i;
}
private int findFreeLocation（）{
int i;
for（i = 0; i< DIRECTORY_SIZE; i ++）
{
if（directory [i] == null）
{
break;
}
}
返回i;
}
public String toString（）{
for（int i = 0; i< DIRECTORY_SIZE; i ++）{
System.out.println （目录[i]）;
}
返回null;
}
}
公共类测试{
public static void main （String [] args）{
ArrayDirectory phoneBook = new ArrayDirectory（）;
phoneBook.addEntry（Bigger，R，2486）;
phoneBook.addEntry（Smaller，E，0423）;
phoneBook.addEntry（Ringer，J，6589）;
phoneBook.addEntry（Looper，T，6723）;
phoneBook.addEntry（Lennon，B，4893）;
phoneBook.addEntry（Martin，M，2121）;
phoneBook.print（）;
}
}
解决方案
Arrays.toString（目录）;只需打印目录，即
类型 Entry 的数组实例，它不会像您期望的那样覆盖 toString（）方法/ p>
另见
I'm making a phone book and filling it with entries. The entries consist of two Strings for surname and initial, and a telephone number. I'm using an array to store the entries. I'm trying to get the array to print out and I've put toString methods in each class. But when I print out i'm still getting "[LEntry;@8dc8569". I'm not sure what I'm doing wrong. Here's the code.
public class Entry {
String surname;
String initial;
int number;
public Entry(String surname, String initial, int number) {
this.surname = surname;
this.initial = initial;
this.number = number;
}
public String getSurname(){
return surname;
}
public String getInitial(){
return initial;
}
public int getNumber() {
return number;
}
void setNumber(int number){
this.number = number;
}
public String toString(){
return surname+ "\t" +initial+ "\t" +number;
}
}
public class ArrayDirectory {
int DIRECTORY_SIZE = 6;
Entry [] directory = new Entry[DIRECTORY_SIZE];
public void addEntry(String surname, String initial, int num) {
int i = findFreeLocation();
directory[i] = new Entry(surname, initial, num);
}
public void deleteEntry(String surname, String initial) {
int i = findEntryIndex(surname, initial);
directory[i] = null;
}
public void deleteEntry(int number) {
int i = findEntryIndex(number);
directory[i] = null;
}
public int findEntry(String surname, String initial) {
int i;
i = findEntryIndex(surname, initial);
return directory[i].getNumber();
}
public void editNum(String surname, String initial, int number) {
int i;
i = findEntryIndex(surname, initial);
directory[i].setNumber(number);
}
public void print() {
// TODO print array
System.out.println(directory);
}
private int findEntryIndex(String surname, String initial) {
int i;
for (i = 0; i <= DIRECTORY_SIZE; i++)
{
if(directory[i] != null && directory[i].getSurname().equals(surname) && directory[i].getInitial().equals(initial))
{
break;
}
}
return i;
}
private int findEntryIndex(int number) {
int i;
for (i = 0; i <= DIRECTORY_SIZE; i++)
{
if(directory[i] != null && directory[i].getNumber() == number)
{
break;
}
}
return i;
}
private int findFreeLocation() {
int i;
for (i = 0; i < DIRECTORY_SIZE; i++)
{
if(directory[i] == null)
{
break;
}
}
return i;
}
public String toString() {
for(int i = 0 ; i< DIRECTORY_SIZE ; i++){
System.out.println( directory[i] );
}
return null;
}
}
public class Test {
public static void main(String[] args) {
ArrayDirectory phoneBook = new ArrayDirectory();
phoneBook.addEntry("Bigger", "R", 2486);
phoneBook.addEntry("Smaller", "E", 0423);
phoneBook.addEntry("Ringer", "J", 6589);
phoneBook.addEntry("Looper", "T", 6723);
phoneBook.addEntry("Lennon", "B", 4893);
phoneBook.addEntry("Martin", "M", 2121);
phoneBook.print();
}
}
解决方案
Arrays.toString(directory);
when you just print directory, which is an instance of array of type Entry, it doesn't override the toString() method the way you are expecting
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