将24小时制的时间转换成12小时制，练习自定义错误处理和简单的正则表达式

将24小时制的时间转换成12小时制，练习自定义异常处理和简单的正则表达式
在异常处理的方面还需要进一步的加强和改善，下一步应该加强对正则表达式的使用。

package com.cn.tibco.time;import java.util.Scanner;public class GetTime {public static void main(String args[]) {GetTime getTime = new GetTime();boolean ison = true;while (ison) {getTime.resetTime();System.out.println("Again?(y/n)");Scanner keyboard = new Scanner(System.in);String yn = keyboard.next();if (yn.equalsIgnoreCase("n")) {ison = false;}}}public void resetTime() {System.out.println("Enter time in 24-hour notation:");Scanner keyboard = new Scanner(System.in);String time = keyboard.nextLine();System.out.println("That is the same as");try {isFormat(time);int hours = getHours(time);int minutes = getMinutes(time);if (hours > 12 && minutes >9) {String h1 = Integer.valueOf(hours - 12).toString();time = h1 + ":" + getMinutes(time) ;System.out.println(time + " pm");} else if ( hours > 12 && minutes <10) {String h1 = Integer.valueOf(hours - 12).toString();time = h1 + ":0" + getMinutes(time) ;System.out.println(time + " pm");}else {System.out.println(time + " am");}} catch (TimeFormatException e) {e.printStackTrace();resetTime();}}//检验时间格式，还需要进一步加强格式的处理。public void isFormat(String time) throws TimeFormatException {        if(!time.contains(":")){throw new TimeFormatException("There is no such time as " + time);}int hours = getHours(time);int minutes = getMinutes(time);if (hours < 0 || hours > 24) {throw new TimeFormatException("There is no such time as " + time);} else if (minutes < 0 || minutes > 59) {throw new TimeFormatException("There is no such time as " + time);}}//得到小时数public int getHours(String time) {int pos;pos = time.indexOf(":");int hours = Integer.parseInt(time.substring(0, pos));return hours;}//得到分钟数public int getMinutes(String time) {int pos;pos = time.indexOf(":");int minutes = Integer.parseInt(time.substring(pos + 1));return minutes;}}

异常处理类

package com.cn.tibco.time;public class TimeFormatException extends Exception {public TimeFormatException(){super();}public TimeFormatException(String message){super(message);}@Overridepublic String getMessage() {return super.getMessage();}}

//使用正则表达式对方法isFormat()进行修正，代码如下：

public void isFormat(String time) throws TimeFormatException {        if(!time.matches("\\d{1,2}\\:\\d{2}")){throw new TimeFormatException("There is no such time as " + time);}int hours = getHours(time);int minutes = getMinutes(time);if (hours < 0 || hours > 24) {throw new TimeFormatException("There is no such time as " + time);} else if (minutes < 0 || minutes > 59) {throw new TimeFormatException("There is no such time as " + time);}}

1 楼 mfkvfn 2012-09-12   你这也太...
用SimpleDateFormat类先用HH:mm:ss来parese一下时间，然后用hh:mm:ss a来format一下不就行了。 2 楼 haohao-xuexi02 2012-09-17   重新封装下。。。如楼上所说。。有封装好的方法 。。直接调用。。即可。。

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