Question

编写一个java程序用以将AM/PM格式的时间转换为24小时格式，求大神完成代码

输入: 9:30pm / 输出: 21:30
输入: 9:30am / 输出: 9:30
输入: 12:30pm / 输出: 12:30
输入: 9:30 / 输出: 9:30
输入: 19:30 / 输出: 19:30
public classTimeConverter {
public static voidmain(String[] args) {
TimeConverter cont = newTimeConverter();
// Test
System.out.println("9:30pm -> "+ cont.convert("9:30pm"));
System.out.println("9:30am -> "+ cont.convert("9:30am"));
System.out.println("12:30pm -> "+ cont.convert("12:30pm"));
System.out.println("9:30 -> "+ cont.convert("9:30"));
System.out.println("19:30 -> "+ cont.convert("19:30"));
}
publicString convert(String ampm) {
//在此处写出解决问题的程序代码 …
}
}

Answer 1

SimpleDateFormat objSDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String strCurrentTime = objSDateFormat.format(Date类型的时间);

注：大写的HH为24小时制，小写的hh为12小时制，当然还可以在ss的后面加上 a，这样可以在后面显示上下文：显示效果为“2008-03-24 17:00:14 下午”

这个更全
实现思路就是输入一个时间，之后会输出相应的12小时和24小时效果展示：
import java.text.SimpleDateFormat;
import java.util.Locale;
import java.util.Scanner;

public class App {

public static void main(String[] args) {
while (true) {
System.out.println("Enter time in 24-hour notation:");
Scanner sc = new Scanner(System.in);
String line = sc.nextLine();
try {
outTime(line);
} catch (TimeFormatException e) {
System.out.println("There is no such time as " + line);
System.out.println("Try again:");
continue;
}
sc = new Scanner(System.in);
line = sc.nextLine();
if ("n".equalsIgnoreCase(line)) {
break;
}

}
System.out.println("End of program");
}

public static void outTime(String line) throws TimeFormatException {
SimpleDateFormat _24time = new SimpleDateFormat("HH:mm");
SimpleDateFormat _12time = new SimpleDateFormat("hh:mm a",
Locale.ENGLISH);
try {
String[] array = line.split(":");
if (Integer.parseInt(array[0]) < 0
|| Integer.parseInt(array[0]) > 23) {
throw new TimeFormatException();
}
if (Integer.parseInt(array[1]) < 0
|| Integer.parseInt(array[1]) > 59) {
throw new TimeFormatException();
}
System.out.println(_12time.format(_24time.parse(line)));
System.out.println("Again?(y/n)");
} catch (Exception e) {
throw new TimeFormatException();
}
}
}
class TimeFormatException extends Exception {

}

Answer 2

public String convert(String ampm) {
// 在此处写出解决问题的程序代码 …
if(ampm.contains("am")){

return ampm.substring(0, ampm.indexOf("am"));
}else if(ampm.contains("pm")){

int i = ampm.indexOf(":");
String s= ampm.substring(0, i);

int hour = Integer.parseInt(s);
if(hour >= 12){

String res = ampm.substring(0, ampm.indexOf("pm"));

return res;
}else{
String sHour = hour+12 + "";
return sHour + ampm.substring(ampm.indexOf(":"), ampm.indexOf("pm"));

}

}else{

return ampm;

}

}
完美解决 看在我这么辛苦的情况下请给采纳加精

Answer 3

public  String convert(String ampm){
		if(ampm.contains("am")){
			ampm=ampm.substring(0,ampm.length()-2);
		}else if(ampm.contains("pm")){
			ampm=ampm.substring(0,ampm.length()-2);
			int hour=Integer.parseInt(ampm.split(":")[0]);
			if(hour<12){
				ampm=(hour+12)+":"+ampm.split(":")[1];
			}
		}
		return ampm;
	}

你看看对不对，写的不太好，请见谅

追问

我想自己输入时间，能改下代码吗

Answer 4

package com.test;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Locale;
public class AmPmUtil
{
 
 public static void main(String[] args)
 {
  try
  {
   System.out.println(AmPmUtil.convert("9:30pm"));
   System.out.println(AmPmUtil.convert("9:30am"));
   System.out.println(AmPmUtil.convert("12:30pm"));
   System.out.println(AmPmUtil.convert("9:30"));
   System.out.println(AmPmUtil.convert("19:30"));
  }
  catch (final ParseException e)
  {
   e.printStackTrace();
  }
 }
 
 /**
  * 转换到24小时
  * @param ampm
  * @return
  * @throws ParseException
  */
 private static String convert(String ampm) throws ParseException
 {
  final SimpleDateFormat format = new SimpleDateFormat("HH:mm");
  SimpleDateFormat parse = null;
  if (ampm.indexOf("m") > -1)
  {
   parse = new SimpleDateFormat("hh:mma", Locale.ENGLISH);
  }
  else
  {
   parse = format;
  }
  return format.format(parse.parse(ampm));
 }
 
}