这个函数将返回一个从java日期对象转换而来的SQL日期。

public static java.sql.Date convertFromJAVADateToSQLDate(
            java.util.Date javaDate) {
        java.sql.Date sqlDate = null;
        if (javaDate != null) {
            sqlDate = new Date(javaDate.getTime());
        }
        return sqlDate;
    }

将java.util.Date转换为java.sql.Date将丢失小时、分钟和秒。所以如果可能的话，我建议你像这样使用java.sql.Timestamp:

prepareStatement.setTimestamp(1, new Timestamp(utilDate.getTime()));

要了解更多信息，您可以检查这个问题。

比较2个日期的方法。日期或sql.date)

 public static boolean isSameDay(Date a, Date b) {
    Calendar calA = new GregorianCalendar();
    calA.setTime(a);

    Calendar calB = new GregorianCalendar();
    calB.setTime(b);

    final int yearA = calA.get(Calendar.YEAR);
    final int monthA = calA.get(Calendar.MONTH);
    final int dayA = calA.get(Calendar.DAY_OF_YEAR);

    final int yearB = calB.get(Calendar.YEAR);
    final int monthB = calB.get(Calendar.MONTH);
    final int dayB = calB.get(Calendar.DAY_OF_YEAR);

    return yearA == yearB && monthA == monthB && dayA == dayB;
}

我认为最好的转变方式是:

static java.sql.Timestamp SQLDateTime(Long utilDate) {
    return new java.sql.Timestamp(utilDate);
}

Date date = new Date();
java.sql.Timestamp dt = SQLDateTime(date.getTime());

如果你想在SQL表中插入dt变量，你可以这样做:

insert into table (expireAt) values ('"+dt+"');

我是一个新手:在四处奔波之后，这是有效的。思想可能有用

     String bufDt =  bDOB.getText();  //data from form
     DateFormat dF = new SimpleDateFormat("dd-MM-yyyy"); //data in form is in this format
     Date bbdt = (Date)dF.parse(bufDt);  // string data is converted into java util date
     DateFormat dsF = new SimpleDateFormat("yyyy-MM-dd"); //converted date is reformatted for conversion to sql.date
     String ndt = dsF.format(bbdt); // java util date is converted to compatible java sql date
     java.sql.Date sqlDate=  java.sql.Date.valueOf(ndt);  // finally data from the form is convered to java sql. date for placing in database

对于另一个答案，你可能会遇到时间信息的问题(比较日期和意想不到的结果!)

我建议:

java.util.Calendar cal = Calendar.getInstance();
java.util.Date utilDate = new java.util.Date(); // your util date
cal.setTime(utilDate);
cal.set(Calendar.HOUR_OF_DAY, 0);
cal.set(Calendar.MINUTE, 0);
cal.set(Calendar.SECOND, 0);
cal.set(Calendar.MILLISECOND, 0);    
java.sql.Date sqlDate = new java.sql.Date(cal.getTime().getTime()); // your sql date
System.out.println("utilDate:" + utilDate);
System.out.println("sqlDate:" + sqlDate);