【Java编程】Java中的字符串匹配

package tengwei.com;

import java.util.regex.Pattern;

import javax.swing.JOptionPane;

public class UseMatchesMethod {

	public static void main(String args[])
	{
		String input = JOptionPane.showInputDialog("请输入有效的电子邮件！");
		String reg = "[a-zA-Z]\\w*[@]\\w+[.]\\w{2,}";
		if(input.matches(reg))
			System.out.println("是有效的电子邮件！");
		else
			System.out.println("不是有效的电子邮件！");
				
		if(Pattern.matches(reg, input))
			System.out.println("是有效的电子邮件");
		else
			System.out.println("不是有效的电子邮件！");

	}
}

package tengwei.com;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class UsePattern {
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		String str="We call this the live-code approach."
				+"These examples are available from three locations-they are "
				+"on the CD that accompanies this book";
		Pattern expression = Pattern.compile("[a-zA-Z]+");//创建匹配模式
		Matcher matcher=expression.matcher(str);//通过匹配模式得到匹配器
		//通过这种方式来进行重复匹配的效率较高
		String word=null;
		int n=0;
		while(matcher.find())//扫描是否有匹配的子串,如果匹配器没有重置，则从当前下一个还没进行匹配的字符开始匹配
		{
			word=matcher.group();//得到匹配的子串
			System.out.println(word+"\t");
			if((n+1)%4==0)//每行显示四个单词
				System.out.println();
			n++;
		}
		
		System.out.print("\n单词总数："+n);
		System.out.println("\n单词字母9个及以上的单词有：");
		Pattern expression1 = Pattern.compile("[a-zA-Z]{9,}");
		Matcher matcher1=expression1.matcher(str);
		while(matcher1.find())
		{
			word=matcher1.group();
			System.out.println(word+"\n");
		}
		System.out.println();
	}

}