Anderson

import java.io.File;
import java.util.Scanner;
import java.io.*;

public class TextScanner {

  public static void main(String[] args) {
   try{
 FileReader fr =  new FileReader("D:\\w.txt");   //FileReader fr
 BufferedReader   br = new BufferedReader(fr); //BufferedReader br
 String a;
 while((a= br.readLine())!=null){
  System.out.print(a);
 }
 fr.close();
 br.close();
   }catch(IOException e){
   System.out.print(e);
   }
  }
}
//定义了一个文件字符输入流对像fr，接著打开输入流文件w.txt并连接成带缓冲的输入流，然后依行读取文本，每次文件text.txt中读出一行



import java.util.regex.*;
   
    public class BasicReplace {
        public static void main(String[] args) {
            CharSequence inputStr = "a b c a b c";
            String patternStr = "a";
            String replacementStr = "x";    //  \r\n 回车换行
    
            // Compile regular expression
            Pattern pattern = Pattern.compile(patternStr);
   
            // Replace all occurrences of pattern in input
            Matcher matcher = pattern.matcher(inputStr);
            String output = matcher.replaceAll(replacementStr);
   System.out.println(output);
            // x b c x b c
        }
    }

regex refer  ：    http://www.regexlab.com/zh/regref.htm

http://java.ccidnet.com/art/297/20060611/576975_1.html   实用工具类