import java.util.regex.Matcher;

import java.util.regex.Pattern;

public class Test3 {

    public static void main(String args[]){

        Pattern pattern = Pattern.compile("[0-9]{4}[-][0-9]{1,2}[-][0-9]{1,2}[ ][0-9]{1,2}[:][0-9]{1,2}[:][0-9]{1,2}");

        Matcher matcher = pattern.matcher("2、开标时间：2018-08-02 14:00:00。2、开标时间：2018-08-02 16:00:00。2、开标时间：2018-08-02 15:00:00。");

        while(matcher.find()){

            System.out.println(matcher.group());

        }

    }

}

2018-08-02 14:00:00

2018-08-02 16:00:00

2018-08-02 15:00:00