Io流字符流和字符流的相互转换

package 字节流转换为字符流;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

public class Demo1 {
    public static void main(String[] args) {
        //System类中的属性  in返回值是 static  InputStream也就是数据类型
        
        InputStream is = System.in;
        BufferedReader br = new BufferedReader(new InputStreamReader(is));
        BufferedWriter bw = null;
        String line = null;
        
        try {
            bw = new BufferedWriter(new FileWriter("b.txt"));
            //不为null就可以一直输入
            while((line = br.readLine())!=null) {
                //输入exit就退出
                if("exit".equals(line)) {
                    break;
                }
                //输入一行数据
                bw.write(line);
                //输入之后换一行
                bw.newLine();
                //一定要清除缓存
                bw.flush();
                
            }
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally {
            if(bw != null) {
                try {
                    bw.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
    
}
}

package 字符流转换为字节流;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.OutputStreamWriter;

public class Demo1 {
    
    public static void main(String[] args) {
        BufferedReader br = null;
        BufferedWriter bw = null;
        try {
            br = new BufferedReader(new FileReader("b.txt"));
            bw = new BufferedWriter(new OutputStreamWriter(System.out));
            String line =     null;
            
            while((line = br.readLine())!=null) {
                bw.write(line);
                bw.newLine();
                bw.flush();
            }
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally {
            try {
                if(bw!=null) {
                    bw.close();
                }
                if(br!=null) {
                    br.close();
                }
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        
    }
}