如何使Java获得一个数字和一个新数字并将它们加在一起

Question

I Have been trying for some time now to get java to get and number and add a neww number to it but have had no luck.

package me.FL.PlayTime;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Scanner;

import org.bukkit.entity.Player;

public class PlayTimePlayer {
    long join = 0;
    Player player = null;

    private File f;
    public PlayTimePlayer(Player player){
        this.player = player;
        this.join = System.currentTimeMillis();

    }

    public void hold(){
        int seconds = (int) ((getMiliPlayTime() / (1000)) % 60);
        int minutes = (int) ((getMiliPlayTime() / (1000*60)) % 60);
        int hours   = (int) ((getMiliPlayTime() / (1000*60*60)) % 24);
        int days    = (int) ((getMiliPlayTime() / (1000*60*60*24)) % 24);
    }

    public int getMiliPlayTime(){
        return (int) (System.currentTimeMillis() - join);
    }

    public int getSeconds(){
        return(int) (getMiliPlayTime() / 1000) % 60 ;
    }

    public int getMinutes(){
        return (int) ((getMiliPlayTime() / (1000*60)) % 60);    
    }

    public int getHours(){
        return (int) ((getMiliPlayTime() / (1000*60*60)) % 24);
    }

    public int getDays(){
        return (int) ((getMiliPlayTime() / (1000*60*60*24)) % 24);
    }

    public String getTime(){
        String ptime = getDays() + ":" + getHours() + ":" + getMinutes() + ":" + getSeconds();
        System.out.println(ptime);
        return ptime;
    }

    public void save() throws IOException{
        if (Playtime.hascreatedfolder = false){
            Scanner s = new Scanner(new File("Fileloc"));
            while(s.hasNextLine()){
            String time = s.nextLine();
            String[] split = time.split(":");

                int days = Integer.parseInt(split[0]);
                int newday = getDays();
                int newTimeday = newday + days;

                int hours = Integer.parseInt(split[1]);
                int newhour = getHours();
                int newTimeHour = newhour + hours;

                int minutes = Integer.parseInt(split[2]);
                int newminute = getMinutes();
                int newTimeminute = newminute + minutes;

                int seconds = Integer.parseInt(split[3]);
                int newsecond = getSeconds();
                int newTimesecond = newsecond + seconds;


                File f = new File("plugins/PlayerTime/");
                f.mkdirs();

                File file = new File(player.getDisplayName() + ".txt");
                if (f.exists());

                f.createNewFile();

                try {
                    BufferedWriter w = new BufferedWriter(new FileWriter(file));
                    w.write(getTime());
                    w.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

i want it to get a time for example lets say it had 1:0:0 and i wanted to add 30 minutes i will like it to get 1:0:0 from a txt file and add 30 minutes from the server i should get 1:30:0 but i get 0:30:0 instead also it overwrited the oldnumbers txt file i dont want it to do this. please let me know how to fix this.

Answer 1

The issue is that here:

try {
    BufferedWriter w = new BufferedWriter(new FileWriter(file));
    w.write(getTime());
    w.close();
} catch (IOException e) {
    e.printStackTrace();
}

You're only writing the new times in; you've not passed your newTimeincrements anywhere or done anything with them. if you were to change it to, say, w.write(newTimeday + ":" + newTimehour + ":" + newTimeminute + ":" + newTimesecond); you would be writing your new values in. If there's a ClassCastException there, you can also use something like

w.write(String.valueOf(newTimeday) + ":" + String.valueOf(newTimehour) + ":" + String.valueOf(newTimeminute) + ":" + String.valueOf(newTimesecond));

I don't use Buffered writers, so I don't know if it'll simply accept the integers in the string without conversion. Second option is just in case it doesn't.

Answer 2

Hard to tell from looking at your code and reading your brief description what exactly you're trying to achieve, so here are a few notes that might help you to get going:

• You have an incorrect boolean condition hascreatedfolder = false , I think you want to use == unless it's meant to be an assignment?
• you have no validation but the code seems to be expecting the format "days:hours:minutes:seconds" with four colon-separated values, whereas from your description you seem to have three ("hours:minutes:seconds").
• You have several unnecessary casts from int to int (not a problem per se, just being pedantic)
• unused instance variable File f (again just being pedantic)

I'd recommend you step through your code with a debugger and see where it's doing something different from what you're expecting.

Edit: As another general tip for what I think you're trying to do, have a look at joda-time and use that to add times/dates.