I'm trying to take a date and pad it with 0's on the left so I can parse it as a date.

static LocalDate cleanDate(String s)
    {
        s = s.replace(',', '-');
        String[] str = s.split("-");
        
        
        String.format("%1$"   2   "s", str[0]).replace(' ', '0');
    }

Initially the string coming in looks like this: "11-2,2020" I need to pad the month and date with 0's on the left so it looks like this "11-02-2020" so I can use my date formatter "MM-dd-yyyy".

Java is unhappy with me passing str[0] and wants it to be an Object[] instead of a String. Every "how to" that I've run into use passing a string in this portion, in fact I have copy pasted several variations of allegedly working code and simply replaced their "input string" or whatever with mine. I keep getting this error. I'm sure I'm doing something stupid, but I'm not sure what is.

Thanks in advance.

CodePudding user response：

java.time

Let the java.time framework do the heavy-lifting here. See tutorial by Oracle.

Define a formatter to match your input.

DateTimeFormatter fInput = DateTimeFormatter.ofPattern( "M-d,uuuu" ) 

Parse.

LocalDate ld = LocalDate.parse( input , fInput ) ;

Define a formatter to match your desired output.

DateTimeFormatter fOutput = DateTimeFormatter.ofPattern( "MM-dd-uuuu" ) ;

Generate text.

String output = ld.format( fOutput ) ;

See this code run at Ideone.com.

CodePudding user response：

Instead of manipulating your string, you can maybe make a parser that fits your needs. For example

String textDate = "11-2,2020";
SimpleDateFormat parser = new SimpleDateFormat("MM-dd,yyyy");
Date date = parser.parse(textDate);

If you need to switch back to text format, you can use another formatter

SimpleDateFormat formatter = new SimpleDateFormat("MM-dd-yyyy");
System.out.println(formatter.format(date));

2 points of attention with the SimpleDateFormat object 1/ It is not threadSafe, so be careful if you use it in a multithreaded context (web service for example) 2/ It's heavy to instantiate, it's better to instantiate it once for all rather than at each call