我一直坚持做这个家庭作业。基本上我必须为读取文件的日期创建一个构造函数，该文件由每一行上的一个日期组成。每个日期都应存储在 Date 对象中。
但是，我必须在阅读后将日期打印为“日期：1997 年 6 月 17 日”，并使用类似于“System.out.println(date);”的内容。
所以我遇到的问题是能够正确地遍历每一行。我有一个 while 循环，它将扫描文本文件中的所有行，但一旦完成，就只能访问最后一行。如何对其进行编码，以便我可以按顺序一次访问每一行？
对于那些感兴趣的人，这是任务。
到目前为止，这是我的代码，如果我在解释我想要做的事情时不够清楚，我很抱歉，我是新手。
public class Date {
private int month; // 1-12
private int monthNum; // number of month
private int day; // 1-31 varies by month
private int year; // any year
private String chkMonth, chkDay;
private String theMonth;
private int theYear,valid;
/**
* days in each month with 0 at the index since there is no month "zero"
*/
private static final int[] daysPerMonth = { 0, 31, 28, 31, 30, 31, 30, 31,
31, 30, 31, 30, 31 };
/**
* constructor: call checkMonth to confirm proper value for month; call
* checkDay to confirm proper value for day
*
* @param theMonth
* the month of the year
* @param theDay
* the day of the month
* @param theYear
* the year
*/
public Date() {
Scanner in = null;
try {
in = new Scanner(new File("dates.txt"));
} catch (FileNotFoundException exception) {
System.err.println("failed to open dates.txt");
System.exit(1);
}
while (in.hasNextLine()) {
theMonth = in.next();
chkMonth = theMonth.replaceAll("\\.", "");
chkMonth = chkMonth.toLowerCase();
chkDay = in.next();
chkDay = chkDay.replaceAll("\\,", "");
day = Integer.parseInt(chkDay);
theYear = in.nextInt();
// need more code for DateRange objects
valid = 1;
year = theYear; // could validate year
if (checkMonth(chkMonth) == 0)
valid = 0; // validate month
if ((checkDay(day)) == 0)
valid = 0; // validate day
System.out.println(this);
}
}
/**
* utility method to confirm proper month value
*
* @param theMonth
* @return testMonth or throw an IllegalArgumentException
*/
private int checkMonth(String theMonth) {
if (((theMonth.compareTo("jan")) == 0)
|| ((theMonth.compareTo("january")) == 0))
monthNum = 1;
else if (((theMonth.compareTo("feb")) == 0)
|| ((theMonth.compareTo("february")) == 0))
monthNum = 2;
else if (((theMonth.compareTo("mar")) == 0)
|| ((theMonth.compareTo("march")) == 0))
monthNum = 3;
else if (((theMonth.compareTo("apr")) == 0)
|| ((theMonth.compareTo("april")) == 0))
monthNum = 4;
else if (((theMonth.compareTo("may")) == 0))
monthNum = 5;
else if (((theMonth.compareTo("june")) == 0))
monthNum = 6;
else if (((theMonth.compareTo("july")) == 0))
monthNum = 7;
else if (((theMonth.compareTo("aug")) == 0)
|| ((theMonth.compareTo("august")) == 0))
monthNum = 8;
else if (((theMonth.compareTo("sept")) == 0)
|| ((theMonth.compareTo("september")) == 0))
monthNum = 9;
else if (((theMonth.compareTo("oct")) == 0)
|| ((theMonth.compareTo("october")) == 0))
monthNum = 10;
else if (((theMonth.compareTo("nov")) == 0)
|| ((theMonth.compareTo("november")) == 0))
monthNum = 11;
else if (((theMonth.compareTo("dec")) == 0)
|| ((theMonth.compareTo("december")) == 0))
monthNum = 12;
if (monthNum > 0 && monthNum <= 12) // validate month
return monthNum;
else
return monthNum = 0;
/*
* else // month is invalid throw new
* IllegalArgumentException("month must be 1-12");
*/
}
/**
* utility method to confirm proper day value based on month and year
*
* @param testDay
* @return testDay or throw an IllegalArgumentException
*/
private int checkDay(int testDay) {
// check if day in range for month
if (testDay > 0 && testDay <= daysPerMonth[monthNum])
return testDay;
// check for leap year
if (monthNum == 2 && testDay == 29
&& (year % 400 == 0 || (year % 4 == 0 && year % 100 != 0)))
return testDay;
// System.out.println("Invalid Date");
return 0;
}
/**
* return a String of the form month/day/year
*
* @return a String of the form month/day/year
*/
public String toString() {
if (valid == 1) {
String ret = "Date: ";
ret += theMonth + " ";
ret += day + ", ";
ret += year;
return ret;
} else
return "Date Invalid";
}
}