使用Java中的循环创建变量名？ [英] Create variable names using a loop in Java?

问题描述

请看下面的代码，用于为每个月的开始和结束生成时间戳在一个财政年度。

  int year = 2010; 
 //财政年度从9月到8月这样早期是那些年= FY-1和晚期的年份是那些年= FY 
 int [] earlyMonths = {8,9,10,11}; // Sept to Dec 
 int earlyYear = year -1; （int i：earlyMonths）
 {
 month = i; 
日历cal = Calendar.getInstance（）; 
 cal.clear（）; 
 cal.set（earlyYear，month，1,0,0,0）; 
 Long start = cal.getTimeInMillis（）; 
 cal.clear（）; 
 cal.set（earlyYear，month，1）; 
 lastDayofMonth = cal.getActualMaximum（GregorianCalendar.DAY_OF_MONTH）; 
 cal.set（earlyYear，month，lastDayofMonth，23,59,59）; 
 Long end = cal.getTimeInMillis（）; 
} 
 int [] lateMonths = {0，1，2，3，4，5，6，7}; // 1月至8月
（int i：lateMonths）{
 month = i; 
日历cal = Calendar.getInstance（）; 
 cal.clear（）; 
 cal.set（年，月，1,0,0,0）; 
 Long start = cal.getTimeInMillis（）; 
 cal.clear（）; 
 cal.set（年，月，1）; 
 lastDayofMonth = cal.getActualMaximum（GregorianCalendar.DAY_OF_MONTH）; 
 cal.set（年，月，lastDayofMonth，23,59,59）; 
 Long end = cal.getTimeInMillis（）; 
} 
  

到目前为止这么好，但为了使用这些结果，我需要这些时间戳被输出到由月份命名的变量（在代码中稍后的准备语句中使用），例如SeptStart = sometimestamp，SeptEnd =某些时间戳等。

不知道是否可以根据每个循环的结果声明新的变量。任何想法？

解决方案

为什么不使用一个 地图 ？

所有你想要一个容器的一些值，并用指定的名称来解决它。

所以只需要将变量名称设为您的密钥和变量值即可，ehm，value。

/ p>

首先，去一个 Treemap 而不是地图。

另外，为了保留字典列表顺序，将您的月数填充为零左右，并使用开始和结束作为分隔符

所以你将拥有：

 code> 01_begin 
 01_end 
 02_begin 
 ... 
 10_begin 
 10_end 
 ... 
  

当您访问树状图时，将以正确的顺序打印。

first time poster, long time reader so be gentle with me :)

See the following code which works to generate me timestamps for the beginning and end of every month in a financial year.

int year = 2010;
// Financial year runs from Sept-Aug so earlyMonths are those where year = FY-1 and lateMonths are those where year = FY
int[] earlyMonths = {8, 9, 10, 11}; // Sept to Dec
int earlyYear = year -1;
for (int i : earlyMonths) {
    month = i;
    Calendar cal = Calendar.getInstance();
    cal.clear();
    cal.set(earlyYear,month,1,0,0,0);
    Long start = cal.getTimeInMillis();
    cal.clear();
    cal.set(earlyYear,month,1);
    lastDayofMonth = cal.getActualMaximum(GregorianCalendar.DAY_OF_MONTH);
    cal.set(earlyYear,month,lastDayofMonth,23,59,59);
    Long end = cal.getTimeInMillis();
}
int[] lateMonths = {0, 1, 2, 3, 4, 5, 6, 7}; // Jan to Aug
for (int i : lateMonths) {
    month = i;
    Calendar cal = Calendar.getInstance();
    cal.clear();
    cal.set(year,month,1,0,0,0);
    Long start = cal.getTimeInMillis();
    cal.clear();
    cal.set(year,month,1);
    lastDayofMonth = cal.getActualMaximum(GregorianCalendar.DAY_OF_MONTH);
    cal.set(year,month,lastDayofMonth,23,59,59);
    Long end = cal.getTimeInMillis();
}

So far so good, but in order to use these results I need these timestamps to be output to variables named by month (to be used in a prepared statement later in the code. e.g. SeptStart = sometimestamp, SeptEnd = some timestamp etc etc.

I don't know if it is possible to declare new variables based on the results of each loop. Any ideas?

解决方案

Why not use a Map?

After all you want to have a "container" for some value and address it with a specified name.

So just make the "variable name" your key and "variable value" your, ehm, value.

Edited because you wanted a Sorted collection:

First of all, go for a Treemap instead of a Map.

Also, to preserve lexicograph order, normalize your month number padding zeroes to the left, and use "begin" and "end" as delimiters

So you will have:

01_begin
01_end
02_begin
...
10_begin
10_end
...

which will get printed in the correct order when you visit the treemap.

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