IO流-复制文本文件的五种方法案例

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
public class Test {
 public static void main(String[] args) throws IOException{

//字符转换流，一次读写一个字符
  /*FileReader fr =new FileReader(new File("11.txt"));
  FileWriter fw = new FileWriter(new File("22.txt"));
  int len =0;
  while((len = fr.read())!=-1){
   fw.write(len);
  }
  if(fr!=null){
   fr.close();
   }
  if(fw!=null){
   fw.close();
  }*/

//字符转换流，一次读写一组字符。
  /*FileReader fr =new FileReader(new File("11.txt"));
  FileWriter fw = new FileWriter(new File("22.txt"));
     char[] chs = new char[1024]; 
        int len = 0; 
        while ((len = fr.read(chs)) != -1) { 
             fw.write(chs, 0, len); 
        } 
       if(fr!=null){
   fr.close();
   }
  if(fw!=null){
   fw.close();
  }*/

//字符缓冲流，一次读写一个字符
/*BufferedReader br =new BufferedReader(new FileReader("11.txt"));
  BufferedWriter bw = new BufferedWriter(new FileWriter("22.txt"));
  int str=0;
  while((str= br.read()) !=-1){
   bw.write(str);
  }
  if(bw!=null){
   bw.close();
  }
  if(br!=null){
   br.close();
  }*/

//字符缓冲流，一次读写一组字符

/*BufferedReader br =new BufferedReader(new FileReader("11.txt"));
  BufferedWriter bw = new BufferedWriter(new FileWriter("22.txt"));
  char[] chs = new char[1024]; 
          int len = 0; 
          while ((len = br.read(chs)) != -1) { 
            bw.write(chs, 0, len); 
          } 
  if(bw!=null){
   bw.close();
  }
  if(br!=null){
   br.close();
  }*/

//字符缓冲流，一次读写一个字符串。
  BufferedReader br =new BufferedReader(new FileReader("11.txt"));
  BufferedWriter bw = new BufferedWriter(new FileWriter("22.txt"));
  String str = null;
  while((str= br.readLine()) !=null){
   bw.write(str);
   bw.newLine();
   bw.flush();
  }
  if(bw!=null){
   bw.close();
  }
  if(br!=null){
   br.close();
  }
 }
}