In my app, I have a requirement to format 12 hours time to 24 hours time. What is the method I have to use?
For example, time like 10:30 AM. How can I convert to 24 hours time in java?
Conversion from 12 hours time to 24 hours time in java
Viewed 131494
17 Answers
12 to 24 hour time conversion and can be reversed if change time formate in output and input SimpleDateFormat class parameter
Test Data Input:
String input = "07:05:45PM"; timeCoversion12to24(input);
output
19:05:45
public static String timeCoversion12to24(String twelveHoursTime) throws ParseException {
//Date/time pattern of input date (12 Hours format - hh used for 12 hours)
DateFormat df = new SimpleDateFormat("hh:mm:ssaa");
//Date/time pattern of desired output date (24 Hours format HH - Used for 24 hours)
DateFormat outputformat = new SimpleDateFormat("HH:mm:ss");
Date date = null;
String output = null;
//Returns Date object
date = df.parse(twelveHoursTime);
//old date format to new date format
output = outputformat.format(date);
System.out.println(output);
return output;
}
static String timeConversion(String s)
{
String s1[]=s.split(":");
char c[]=s1[2].toCharArray();
if(s1[2].contains("PM"))
{
int n=Integer.parseInt(s1[0]);
n=n+12;
return n+":"+s1[1]+":"+c[0]+c[1];
}
else``
return s1[0]+":"+s1[1]+":"+c[0]+c[1];
}
Using LocalTime in Java 8, LocalTime has many useful methods like getHour() or the getMinute() method,
For example,
LocalTime intime = LocalTime.parse(inputString, DateTimeFormatter.ofPattern("h:m a"));
String outtime = intime.format(DateTimeFormatter.ISO_LOCAL_TIME);
In some cases, First line alone can do the required parsing
Try this to calculate time difference between two times.
first it will convert 12 hours time into 24 hours then it will take diff between two times
String a = "09/06/18 01:55:33 AM";
String b = "07/06/18 05:45:33 PM";
String [] b2 = b.split(" ");
String [] a2 = a.split(" ");
SimpleDateFormat displayFormat = new SimpleDateFormat("HH:mm:ss");
SimpleDateFormat parseFormat = new SimpleDateFormat("hh:mm:ss a");
String time1 = null ;
String time2 = null ;
if ( a.contains("PM") && b.contains("AM")) {
Date date = parseFormat.parse(a2[1]+" PM");
time1 = displayFormat.format(date);
time2 = b2[1];
}else if (b.contains("PM") && a.contains("AM")) {
Date date = parseFormat.parse(a2[1]+" PM");
time1 = a2[1];
time2 = displayFormat.format(date);
}else if (a.contains("PM") && b.contains("PM")){
Date datea = parseFormat.parse(a2[1]+" PM");
Date dateb = parseFormat.parse(b2[1]+" PM");
time1 = displayFormat.format(datea);
time2 = displayFormat.format(dateb);
}
System.out.println(time1);
System.out.println(time2);
SimpleDateFormat format = new SimpleDateFormat("HH:mm:ss");
Date date1 = format.parse(time1);
Date date2 = format.parse(time2);
long difference = date2.getTime() - date1.getTime();
System.out.println(difference);
System.out.println("Duration: "+DurationFormatUtils.formatDuration(difference, "HH:mm"));
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This is the extract of code that I have done.
String s="08:10:45";
String[] s1=s.split(":");
int milipmHrs=0;
char[] arr=s1[2].toCharArray();
boolean isFound=s1[2].contains("PM");
if(isFound){
int pmHrs=Integer.parseInt(s1[0]);
milipmHrs=pmHrs+12;
return(milipmHrs+":"+s1[1]+":"+arr[0]+arr[1]);
}
else{
return(s1[0]+":"+s1[1]+":"+arr[0]+arr[1]);
}
import java.text.SimpleDateFormat;
import java.text.DateFormat;
import java.util.Date;
public class Main {
public static void main(String [] args){
try {
DateFormat parseFormat = new SimpleDateFormat("dd-MM-yyyy hh:mm:ss a");
String sDate = "22-01-2019 9:0:0 PM";
Date date = parseFormat.parse(sDate);
SimpleDateFormat displayFormat = new SimpleDateFormat("dd-MM-yyyy HH:mm:ss");
sDate = displayFormat.format(date);
LOGGER.info("The required format : " + sDate);
} catch (Exception e) {}
}
}
I have written a simple utility function.
public static String convert24HourTimeTo12Hour(String timeStr) {
try {
DateFormat inFormat = new SimpleDateFormat( "HH:mm:ss");
DateFormat outFormat = new SimpleDateFormat( "hh:mm a");
Date date = inFormat.parse(timeStr);
return outFormat.format(date);
}catch (Exception e){}
return "";
}
Try this below code,
public static String timeConversion(String s) {
String militaryTime = "";
String hourString = s.substring(0,2);
String timeFormat = s.substring(8,10);
String timeBody = s.substring(2,8);
if (timeFormat.equals("AM")){
if (hourString.equals("12")){
militaryTime = "00" + timeBody;
}else{
militaryTime = hourString + timeBody;
}
}else if (timeFormat.equals("PM")){
if (hourString.equals("12")){
militaryTime = hourString + timeBody;
}else{
int value = Integer.parseInt(hourString) + 12;
militaryTime = String.valueOf(value) + timeBody;
}
}
return militaryTime;
}
It can be done using Java8 LocalTime. Here is the code.
import java.time.LocalTime;
import java.time.format.DateTimeFormatter;
public class TimeConversion {
public String timeConversion(String s) {
LocalTime.parse(s, DateTimeFormatter.ofPattern("hh:mm a"));
}
}
And Here is the test cases for the same:
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;
class TimeConversionTest {
@Test
void shouldReturnTimeIn24HrFormat() {
TimeConversion timeConversion = new TimeConversion();
Assertions.assertEquals("22:30", timeConversion.timeConversion("10:30 PM"));
}
}
Without using library methods
public static String timeConversion(String s) {
String[] timeElements = s.split(":");
if (s.contains("PM")) {
timeElements[0] = getPMHours(timeElements[0]);
} else {
timeElements[0] = getAMHours(timeElements[0]);
}
timeElements[2] = timeElements[2].substring(0,2);
return timeElements[0]+":"+timeElements[1]+":"+timeElements[2];
}
private static String getAMHours(String hour) {
if(Integer.parseInt(hour) == 12) return "00";
return hour;
}
private static String getPMHours(String hour) {
int i = Integer.parseInt(hour);
if(i != 12) return 12+i+"";
return i+"";
}
We can solve this by using String Buffer String s;
static String timeConversion(String s) {
StringBuffer st=new StringBuffer(s);
for(int i=0;i<=st.length();i++){
if(st.charAt(0)=='0' && st.charAt(1)=='1' &&st.charAt(8)=='P' ){
// if(st.charAt(2)=='1'){
// st.replace(1,2,"13");
st.setCharAt(0, '1');
st.setCharAt(1, '3');
}else if(st.charAt(0)=='0' && st.charAt(1)=='2' &&st.charAt(8)=='P' ){
// if(st.charAt(2)=='1'){
// st.replace(1,2,"13");
st.setCharAt(0, '1');
st.setCharAt(1, '4');
}else if(st.charAt(0)=='0' && st.charAt(1)=='3' &&st.charAt(8)=='P' ){
// if(st.charAt(2)=='1'){
// st.replace(1,2,"13");
st.setCharAt(0, '1');
st.setCharAt(1, '5');
}else if(st.charAt(0)=='0' && st.charAt(1)=='4' &&st.charAt(8)=='P' ){
// if(st.charAt(2)=='1'){
// st.replace(1,2,"13");
st.setCharAt(0, '1');
st.setCharAt(1, '6');
}else if(st.charAt(0)=='0' && st.charAt(1)=='5' &&st.charAt(8)=='P' ){
// if(st.charAt(2)=='1'){
// st.replace(1,2,"13");
st.setCharAt(0, '1');
st.setCharAt(1, '7');
}else if(st.charAt(0)=='0' && st.charAt(1)=='6' &&st.charAt(8)=='P' ){
// if(st.charAt(2)=='1'){
// st.replace(1,2,"13");
st.setCharAt(0, '1');
st.setCharAt(1, '8');
}else if(st.charAt(0)=='0' && st.charAt(1)=='7' &&st.charAt(8)=='P' ){
// if(st.charAt(2)=='1'){
// st.replace(1,2,"13");
st.setCharAt(0, '1');
st.setCharAt(1, '9');
}else if(st.charAt(0)=='0' && st.charAt(1)=='8' &&st.charAt(8)=='P' ){
// if(st.charAt(2)=='1'){
// st.replace(1,2,"13");
st.setCharAt(0, '2');
st.setCharAt(1, '0');
}else if(st.charAt(0)=='0' && st.charAt(1)=='9' &&st.charAt(8)=='P' ){
// if(st.charAt(2)=='1'){
// st.replace(1,2,"13");
st.setCharAt(0, '2');
st.setCharAt(1, '1');
}else if(st.charAt(0)=='1' && st.charAt(1)=='0' &&st.charAt(8)=='P' ){
// if(st.charAt(2)=='1'){
// st.replace(1,2,"13");
st.setCharAt(0, '2');
st.setCharAt(1, '2');
}else if(st.charAt(0)=='1' && st.charAt(1)=='1' &&st.charAt(8)=='P' ){
// if(st.charAt(2)=='1'){
// st.replace(1,2,"13");
st.setCharAt(0, '2');
st.setCharAt(1, '3');
}else if(st.charAt(0)=='1' && st.charAt(1)=='2' &&st.charAt(8)=='A' ){
// if(st.charAt(2)=='1'){
// st.replace(1,2,"13");
st.setCharAt(0, '0');
st.setCharAt(1, '0');
}else if(st.charAt(0)=='1' && st.charAt(1)=='2' &&st.charAt(8)=='P' ){
st.setCharAt(0, '1');
st.setCharAt(1, '2');
}
if(st.charAt(8)=='P'){
st.setCharAt(8,' ');
}else if(st.charAt(8)== 'A'){
st.setCharAt(8,' ');
}
if(st.charAt(9)=='M'){
st.setCharAt(9,' ');
}
}
String result=st.toString();
return result;
}
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