JAva StringとDateタイプ間の相互変換

package test; 
import java.text.DateFormat; 
import java.text.SimpleDateFormat; 
import java.text.ParseException; 
import java.util.Date; 
public class StringOrDate { 
    public static String dateToString(Date date, String type) { 
        String str = null; 
        DateFormat format = new SimpleDateFormat("yyyy-MM-dd"); 
        if (type.equals("SHORT")) { 
            // 07-1-18 
            format = DateFormat.getDateInstance(DateFormat.SHORT); 
            str = format.format(date); 
        } else if (type.equals("MEDIUM")) { 
            // 2007-1-18 
            format = DateFormat.getDateInstance(DateFormat.MEDIUM); 
            str = format.format(date); 
        } else if (type.equals("FULL")) { 
            // 2007 1 18      
            format = DateFormat.getDateInstance(DateFormat.FULL); 
            str = format.format(date); 
        } 
        return str; 
    } 
    public static Date stringToDate(String str) { 
        DateFormat format = new SimpleDateFormat("yyyy-MM-dd"); 
        Date date = null; 
        try { 
            // Fri Feb 24 00:00:00 CST 2012 
            date = format.parse(str);  
        } catch (ParseException e) { 
            e.printStackTrace(); 
        } 
        // 2012-02-24 
        date = java.sql.Date.valueOf(str); 
                                              
        return date; 
    } 
    public static void main(String[] args) { 
        Date date = new Date(); 
        System.out.println(StringOrDate.dateToString(date, "MEDIUM")); 
        String str = "2012-2-24"; 
        System.out.println(StringOrDate.stringToDate(str)); 
    } 
}