我的數據作業&算法類告訴我們創建一個系統任務工作順序程序。它要求我們執行各種操作,比如向數組添加一個新的SystemTask對象,刪除任務並列出/打印已排序的對象數組。JAVA:Object Array只打印最後一個元素
我已經完成了大部分編碼工作,但是我一直在打印出我的對象數組。看來無論我添加到對象數組中的最後一個數據是什麼,它都會成爲我數組中所有元素的數據。
一些指令:
- 我的工作訂單()構造函數必須將4默認SystemTask對象在數組中。
- listSystemTask()方法列出數組中所有SystemTask對象(按順序),前面有一個數字。
注意:請不要告訴我使用List或任何先行java 方法。我的家庭作業有其侷限性。
SystemTask類
public class SystemTask{
private static String month, message;
private static int day, hour, minute;
//constructor methods
public SystemTask(){
month = "Jan";
day = 1;
hour = 00;
minute = 00;
message = "Task Here";
}
public SystemTask(String mon, int d, int h, int mnt, String msg){
month = mon;
day = d;
hour = h;
minute = mnt;
message = msg;
/*setMonth(mon);
setDay(d);
setHour(h);
setMinute(mnt);
setMessage(msg);*/
}
//get and set methods
public static String getMonth(){
return month;
}
public static int getDay(){
return day;
}
public static int getHour(){
return hour;
}
public static int getMinute(){
return minute;
}
public static String getMessage(){
return message;
}
public static void setMonth (String mon){
if(mon.length()!= 3)
System.out.println("Invalid 3 Letter Code. Try Again.");
else
month = mon;
}
public static void setDay(int d){
if(d<1 || d>31)
System.out.println("Invalid Day. Try Again.");
else
day = d;
}
public static void setHour(int h){
if(h<0 || h>23)
System.out.println("Invalid Hour. Try Again.");
else
hour = h;
}
public static void setMinute(int mnt){
if(mnt<0 || mnt>59)
System.out.println("Invalid Minute. Try Again.");
else
minute = mnt;
}
public static void setMessage(String msg){
if(msg.length()<1 || msg.length()>40)
System.out.println("Invalid Message. Try Again.");
else
message = msg;
}
@Override
public String toString(){
return getMonth()+" "+getDay()+", "+String.format("%02d",getHour())
+":"+String.format("%02d",getMinute())+" "+getMessage();
}
}
工單類
public class WorkOrders {
private final SystemTask[] ary = new SystemTask[20]; //declare private 20 objects array
//public static int index, empty;
public static void main(String args[]){
WorkOrders object = new WorkOrders(); //create a WorkOrders object
object.run(); //call a run method
}
public WorkOrders(){
// for(int i = 0;i<ary.length;i++){
// ary[i] = new SystemTask();
// }
/*SystemTask t1 = new SystemTask("Mar", 4, 21, 30, "Backup Users");
ary[0] = t1;
SystemTask t2 = new SystemTask("Apr", 1, 17, 0, "Upgrade Hard Drives");
ary[1] = t2;
SystemTask t3 = new SystemTask("May", 6, 10, 45, "Virus Scan");
ary[2] = t3;
SystemTask t4 = new SystemTask("Jun", 3, 9, 15, "Database Backup");
ary[3] = t4;*/
ary[0] = new SystemTask("Mar", 4, 21, 30, "Backup Users");
ary[1] = new SystemTask("Apr", 1, 17, 0, "Upgrade Hard Drives");
ary[2] = new SystemTask("May", 6, 10, 45, "Virus Scan");
ary[3] = new SystemTask("Jun", 3, 9, 15, "Database Backup");
}
public void run(){
char choice;
do{
System.out.println("SYSTEM WORKORDER PROGRAM:");
System.out.println("A)dd SystemTask");
System.out.println("D)elete SystemTask");
System.out.println("L)ist SystemTask");
System.out.println("E)xit");
System.out.print("Select an option: ");
choice = UserInput.getChar();
switch (choice) {
case 'a':
case 'A':
//addSystemTask();
break;
case 'd':
case 'D':
//deleteSystemTask();
break;
case 'l':
case 'L':
listSystemTask();
break;
case 'e':
case 'E':
System.out.println("You quit the program.");
System.out.println("\nThanks for using System Workorder!");
System.exit(0);
break;
default:
System.out.println("\'" + choice + "\' does not exist. Try again.");
break;
}
System.out.println();
}while(choice !='E'|| choice !='e');
}
public void listSystemTask(){
System.out.println("\nALL LISTED TASKS");
for(int c=0;c<ary.length;c++){
if(ary[c]!=null)
System.out.println(c+1 + ": " + ary[c].toString());
}
}
還有一種UserInput類,我做了。我沒有包括它,因爲它僅僅用於我的鍵盤輸入。我省略了一些與我的問題無關的代碼/方法。我只關心打印數組中的對象。
這裏的問題是,這是我所得到的輸出,當我打印的清單:
SYSTEM WORKORDER PROGRAM:
A)dd SystemTask
D)elete SystemTask
L)ist SystemTask
E)xit
Select an option: L
ALL LISTED TASKS
1: Jun 3, 09:15 Database Backup
2: Jun 3, 09:15 Database Backup
3: Jun 3, 09:15 Database Backup
4: Jun 3, 09:15 Database Backup
我不知道哪裏出了問題的來源。我懷疑它是在構造函數中初始化數組,但我似乎無法修復它。或者也許在其他地方?
的可能的複製[爲什麼我的ArrayList中包含的最後一個項目的N份添加到列表中?](http://stackoverflow.com/questions/19843506/why-does-my-arraylist-contain- n-copies-of-the-last-item-added-to-the-list) –
順便說一下,你不能將對象添加到數組中。數組有固定大小。所以,你寧願「設置」到陣列 –