Java ThreadLocal 线程安全问题解决方案

public class ThreadLocalDateUtil {
  private static final String date_format = "yyyy-MM-dd HH:mm:ss";
  private static ThreadLocal<DateFormat> threadLocal = new ThreadLocal<DateFormat>();
 
  public static DateFormat getDateFormat() 
  { 
    DateFormat df = threadLocal.get(); 
    if(df==null){ 
      df = new SimpleDateFormat(date_format); 
      threadLocal.set(df); 
    } 
    return df; 
  } 
  public static String formatDate(Date date) throws ParseException {
    return getDateFormat().format(date);
  }
  public static Date parse(String strDate) throws ParseException {
    return getDateFormat().parse(strDate);
  } 
}

public class DateSyncUtil {
  private static SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    
  public static String formatDate(Date date)throws ParseException{
    synchronized(sdf){
      return sdf.format(date);
    } 
  }
   
  public static Date parse(String strDate) throws ParseException{
    synchronized(sdf){
      return sdf.parse(strDate);
    }
  }
}