例外情况是: java.util.Date 对象，而不是

As the exception says: Calendar::getTime() returns a java.util.Date object, not a java.sql.Timestamp object. So you cannot cast it to a Timestamp object.

使用:

Timestamp timestamp = new Timestamp(cal.getTimeInMillis());

并且还考虑替换 Calendar 和新的日期&Java SE 8中引入了Time API .