Java正则表达式的几个例子

public class MatchesTest
{
	public static void main(String[] args)
	{
		String[] mails =
		{
			"kongyeeku@163.com" ,
			"kongyeeku@gmail.com",
			"ligang@crazyit.org",
			"wawa@abc.xx"
		};
		String mailRegEx = "\\w{3,20}@\\w+\\.(com|org|cn|net|gov)";
		Pattern mailPattern = Pattern.compile(mailRegEx);
		Matcher matcher = null;
		for (String mail : mails)
		{
			if (matcher == null)
			{
				matcher = mailPattern.matcher(mail);
			}
			else
			{
				matcher.reset(mail);
			}
			String result = mail + (matcher.matches() ? "是" : "不是")
				+ "一个有效的邮件地址！";
			System.out.println(result);
		}
	}
}

public class FindGroup
{
	public static void main(String[] args)
	{
		// 使用字符串模拟从网络上得到的网页源码
		String str = "我想求购一本《疯狂Java讲义》，尽快联系我13500006666"
			+ "交朋友，电话号码是13611125565"
			+ "出售二手电脑，联系方式15899903312";
		// 创建一个Pattern对象，并用它建立一个Matcher对象
		// 该正则表达式只抓取13X和15X段的手机号，
		// 实际要抓取哪些电话号码，只要修改正则表达式即可。
		Matcher m = Pattern.compile("((13\\d)|(15\\d))\\d{8}")
			.matcher(str);
		// 将所有符合正则表达式的子串（电话号码）全部输出
		while(m.find())
		{
			System.out.println(m.group());
		}
	}
}

public class ReplaceTest
{
	public static void main(String[] args)
	{
		String[] msgs =
		{
			"Java has regular expressions in 1.4",
			"regular expressions now expressing in Java",
			"Java represses oracular expressions"
		};
		Pattern p = Pattern.compile(" re\\w*");
		Matcher matcher = null;
		for (int i = 0 ; i < msgs.length ; i++)
		{
			if (matcher == null)
			{
				matcher = p.matcher(msgs[i]);
			}
			else
			{
				matcher.reset(msgs[i]);
			}
			System.out.println(matcher.replaceAll("哈哈:)"));
		}
	}
}

public class StringReg
{
	public static void main(String[] args)
	{
		String[] msgs =
		{
			"Java has regular expressions in 1.4",
			"regular expressions now expressing in Java",
			"Java represses oracular expressions"
		};
		for (String msg : msgs)
		{
			System.out.println(msg.replaceFirst("re\\w*" , "哈哈:)"));
			System.out.println(Arrays.toString(msg.split(" ")));
		}
	}
}

public class StartEnd
{
    public static void main(String[] args)
    {
        // 创建一个Pattern对象，并用它建立一个Matcher对象
        String regStr = "Java is very easy!";
        System.out.println("目标字符串是：" + regStr);
        Matcher m = Pattern.compile("\\w+")
            .matcher(regStr);
        while(m.find())
        {
            System.out.println(m.group() + "子串的起始位置："
                + m.start() + "，其结束位置：" + m.end());
        }
    }
}