总结java.sql.Time对象

Question

I have a list of time objects (representing the length of a song) that I would like to add together to get the total time.

Looking at the documentation for java.sql.Time objects it seems that the date part should be untouched and the number of milliseconds will represent the number of milliseconds since 1 Jan 1970, with a negative value meaning before 1970.

I have a Time object (lets call it time ) in the format 00:06:25 ie 6 mins 25 secs. If I call new Date(time.getTime()) I get Thu Jan 01 00:06:25, which is sensible. However, when I simply print the value of getTime() I get a value of -3215000, which makes absolutely no sense, this value would indicate that the time was before 1 Jan 1970...which it isn't.

Therefore when I try to add multiple calls of getTime() together (like 00:03:35/-3385000) I get a more and more negative number (-6600000).

So when I then try and create a new Time object with that value I get 23:10:00 rather than 00:09:00.

Answer 1

I created a test job that displayed the following output:

1 Jan 1970 00:06:25 GMT
1 Jan 1970 00:03:35 GMT
1 Jan 1970 00:03:18 GMT
1 Jan 1970 00:04:22 GMT
1 Jan 1970 00:03:47 GMT
1 Jan 1970 00:00:00 GMT

1 Jan 1970 00:21:27 GMT

The last Time is the sum of the preceding 6 times

The trick is to use the toGMTString() (depreciated) method of Time to generate the output string.

Here's the code I used:

package com.ggl.testing;

import java.sql.Time;

public class AddDates implements Runnable {

    private Time[] songLength;

    public AddDates() {
        this.songLength = new Time[6];
        long time = (6L * 60 + 25) * 1000;
        songLength[0] = new Time(time);
        time = (3L * 60 + 35) * 1000;
        songLength[1] = new Time(time);
        time = (3L * 60 + 18) * 1000;
        songLength[2] = new Time(time);
        time = (4L * 60 + 22) * 1000;
        songLength[3] = new Time(time);
        time = (3L * 60 + 47) * 1000;
        songLength[4] = new Time(time);
        time = 0L;
        songLength[5] = new Time(time);
    }

    @Override
    public void run() {
        long sum = 0L;
        for (int i = 0; i < songLength.length; i++) {
            sum += songLength[i].getTime();
            System.out.println(songLength[i].toGMTString());
        }

        Time totalTime = new Time(sum);
        System.out.println(totalTime.toGMTString());
    }

    public static void main(String[] args) {
        new AddDates().run();
    }

}