正则表达式获取

package dkc_Parrtern1;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/*
     正则表达式的获取
         配合IO流，从一个文本读取文件，获取文件里面单词的个数
 */
public class RegexDemo7 {
    public static void main(String[] args) {
        //在E盘的word.txt中随便写入几行汉字加单词
        /*大家好！hello everybody，我来自寒寨，
        My name is duxiansen,I come from HanZhai.哈哈*/
        File file = new File("E:word.txt");
        //1.读取文件声明BufferedReader对象br
        BufferedReader br = null;
        //2.创建Pattern的对象,传入一个正则表达式
        Pattern p = null;
        //3.调用p对象中的matcher 获取匹配器对象
        Matcher matcher = null;
        //4.定义计算器
        int count = 0;
        try {
            br = new BufferedReader(new FileReader(file));
            String str ="";
            while((str = br.readLine()) != null) {
                p = Pattern.compile("b[a-zA-Z]+b");
                matcher = p.matcher(str);
                while(matcher.find()) {
                    count++;
                }
            }
            System.out.println(count);
            br.close();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } 
    }
}

package dkc_Parrtern1;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

/*
     正则表达式的获取功能:
     Pattern和Matcher类的使用
         jin tian yao xia yu,da jia pa bu pa?huang bu huang? are you sure?
         获取由三个字符组成的单词
 */
public class RegexDemo6 {
    public static void main(String[] args) {
        String str = "jin tian yao xia yu,da jia pa bu pa?huang bu huang? are you sure?";
        //1.创建Pattern的对象,传入一个正则表达式
        Pattern p = Pattern.compile("b[a-zA-Z]{3}b");//(b单词的边界)
        
        //调用p对象中的matcher 获取匹配器对象
        Matcher matcher = p.matcher(str);
        
        //遍历得结果
        int count = 0;
        while(matcher.find()) {
            System.out.print(matcher.group()+" ");
            count++;
        }
        System.out.println(count);
        // 不能单独使用，必须和found方法配合使用，否则报错:No match found 
        //System.out.println(matcher.group());
    }
}