DanStory

Date Type 변경
- format 변경 = .format
- Type 변경 = .parse

1. 소스 코드

String time = "2020/10/15 17:37:15"  // 시간
int minute = 30;  // 분

SimpleDateFormat fm1 = new SimpleDateFormat("yyyy/mm/dd HH:mm:ss");


//1. String to Date
Date StringToDate;
StringToDate = fm1.parse(time);
System.out.println("1. String to Date");
System.out.println("String -> Date : "+StringToDate);
System.out.println("String -> Date : "+StringToDate.getClass()+"\n");

//2. Date to String
String DateToString;
DateToString = StringToDate.toString();
System.out.println("2. Date to String");
System.out.println("Date -> String : "+DateToString);
System.out.println("Date -> String : "+DateToString.getClass()+"\n");

//3. String change Format
String chg_dateFormat;
chg_dateFormat = fm2.format(StringToDate);
System.out.println("3. String change DateFormat");
System.out.println("String Change DateFormat : "+chg_dateFormat);
System.out.println("StringToDate Type : "+chg_dateFormat.getClass());

//4. Time Add           
String beforeTime ="2020/09/30 17:30:15";
String afterTime ="";

int minute = 30;
int hour = 1;
int day = 2;

Date D;
Calendar cal = Calendar.getInstance();
D = fm1.parse(beforeTime);
cal.setTime(D);
cal.add(Calendar.DAY_OF_WEEK, day);
cal.add(Calendar.MINUTE, minute);
cal.add(Calendar.HOUR, hour);
afterTime = fm1.format(cal.getTime());

System.out.println("4. Time Add");
System.out.println("before : "+beforeTime);
System.out.println("after  : "+afterTime);

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2. 실행 결과