Java:如何在Timestamp中添加秒数？

Question

我无法在Java Timestamp中添加秒数.

我有这个,但它给了我相同的日期:

int sec = 600;

java.sql.Timestamp ts_from_ws = new java.sql.Timestamp(retry_date);
Calendar cal = Calendar.getInstance();
cal.setTimeInMillis(ts_from_ws.getTime());
cal.add(Calendar.SECOND,sec);
java.sql.Timestamp ts_new_date_ws = new java.sql.Timestamp(cal.getTime().getTime());

Answer 1

你得到的代码对我有用.作为一个简短但完整的计划:

import java.util.*;
import java.sql.*;

public class Test {
    public static void main(String[] args) {
        long retryDate = System.currentTimeMillis();

        int sec = 600;

        Timestamp original = new Timestamp(retryDate);
        Calendar cal = Calendar.getInstance();
        cal.setTimeInMillis(original.getTime());
        cal.add(Calendar.SECOND, sec);
        Timestamp later = new Timestamp(cal.getTime().getTime());

        System.out.println(original);
        System.out.println(later);
    }
}

输出:

2011-11-07 10:27:45.302
2011-11-07 10:37:45.302

注意10分钟的差异,即600秒.

当然你会以这种方式失去亚毫秒级的精度,这可能并不理想 - 而且它与我通常首先使用的时间戳相反 - 但它确实增加了秒......

另一种选择是Timestamp直接使用:

Timestamp original = ...;
Timestamp later = new Timestamp(original.getTime() + (sec * 1000L));
later.setNanos(original.getNanos());

Answer 2

我总是喜欢简洁:

int sec = 600;

Timestamp later = new Timestamp(retry_date.getTime() + sec * 1000);

或者如果你想要相对于"现在":

Timestamp later = new Timestamp(System.currentTimeMillis() + sec * 1000);

Answer 3

在java 8中，您可以利用新的java.time.Instant. 在 中，从java 1.8java.sql.TimeStamp添加了两个新方法：和。public static Timestamp from(Instant instant)public Instant toInstant()

因此，要添加秒，我们可以将其转换TimeStamp为 Instant，然后调用plusSeconds，然后返回 TimeStamp：

Timestamp ts_from_ws = new Timestamp(retry_date);
Instant next600Sec = ts_from_ws.toInstant().plusSeconds(600);
Timestamp ts_new_date_ws = TimeStamp.from(next600Sec);

或者一行：

Timestamp ts_new_date_ws = TimeStamp.from(new Timestamp(retry_date).toInstant().plusSeconds(600))