java: long to Date/Time/Timestamp

java中，long转换成日期格式有下面三种情况

1、long to Date

System.out.println("java.sql.Date:"   new java.sql.Date(l));

结果：java.sql.Date:1970-01-15

2、long toTime

System.out.println("java.sql.Time:"   new java.sql.Time(l));

结果：java.sql.Time:14:46:40

3、long to Timestamp

System.out.println("java.sql.Timestamp:"   new java.sql.Timestamp(l));

结果：java.sql.Timestamp:1970-01-15 14:46:40.234