Java 时间字符串(HH:mm:ss.SSS) 转换成毫秒(milliseconds)

1、通过SimpleDateFormat

package se.wederbrand.milliseconds;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.TimeZone;
public class Main {        
    public static void main(String[] args) throws Exception {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
        sdf.setTimeZone(TimeZone.getTimeZone("UTC"));
        String inputString = "00:01:30.500";
        Date date = sdf.parse("1970-01-01 " + inputString);
        System.out.println("in milliseconds: " + date.getTime());        
    }
}

注意：

• 所有日期均在内部以UTC表示 
• getTime() 返回自1970-01-01 00:00:00 UTC以来的毫秒数

2、通过正则表达式

private static Pattern pattern = Pattern.compile("(\\d{2}):(\\d{2}):(\\d{2}).(\\d{3})");
public static long dateParseRegExp(String period) {
    Matcher matcher = pattern.matcher(period);
    if (matcher.matches()) {
        return Long.parseLong(matcher.group(1)) * 3600000L 
            + Long.parseLong(matcher.group(2)) * 60000 
            + Long.parseLong(matcher.group(3)) * 1000 
            + Long.parseLong(matcher.group(4)); 
    } else {
        throw new IllegalArgumentException("Invalid format " + period);
    }
}