Java从一个文本文件里面统计某个字符串出现的次数

package com.xixi.test02;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

//从文件（D:\\test.txt）中查出字符串”test”出现的次数？
public class Test03 {
	public static void main(String[] args) {
		BufferedReader br = null;
		try {
			br = new BufferedReader(new FileReader("D:\\test.txt"));
			StringBuffer sb = new StringBuffer();
			String str = null;
			while((str = br.readLine()) != null) {
				sb.append(str);
			}
			
			String regex = "test";
			Pattern pattern = Pattern.compile(regex);
			Matcher matcher = pattern.matcher(sb);
			
			int num = 0;
			while(matcher.find()) {
				num++;
			}
			
			System.out.println("次数为： " + num);
			
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally {
			try {
				if(null != br) {
					//关闭资源
					br.close();
				}
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		
	}
}