IO、键盘输入流

package CoreJavaPractice;
import java.io.*;
public class Practice_1 {
        public static void main(String[] args) throws IOException  {
        
            // 键盘输入流
            BufferedReader  bufr = 
                    new BufferedReader(new InputStreamReader(System.in));
            

            BufferedWriter bufw =
                    new BufferedWriter(new OutputStreamWriter(System.out));
            
            String line = null;
            while((line=bufr.readLine())!=null)
            {
                if("over".equals(line))
                {
                    break;
                }
                bufw.write(line.toUpperCase());
                bufw.newLine();
                bufw.flush();
            }
            bufr.close();
            bufw.close();
        }
        
}
1 源：键盘
目的地：控制台
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2 新需求： 
源：键盘
目的地：文件

package CoreJavaPractice;
import java.io.*;
public class Practice_1 {
        public static void main(String[] args) throws IOException  {
        

            BufferedReader  bufr = 
                    new BufferedReader(new InputStreamReader(System.in));
            
            BufferedWriter bufw =
                    new BufferedWriter(new OutputStreamWriter(new FileOutputStream("out.txt")));
            
            String line = null;
            while((line=bufr.readLine())!=null)
            {
                if("over".equals(line))
                {
                    break;
                }
                bufw.write(line.toUpperCase());
                bufw.newLine();
                bufw.flush();
            }
            bufr.close();
            bufw.close();

            
        }
        
}
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3：需求：想要将一个文件的数据打印在控制台上

源：文件

目的地：控制台

package CoreJavaPractice;
import java.io.*;
public class Practice_1 {
        public static void main(String[] args) throws IOException  {
        

            BufferedReader  bufr = 
                    new BufferedReader(new InputStreamReader(new FileInputStream("PracticeUse.java")));
            
            BufferedWriter bufw =
                    new BufferedWriter(new OutputStreamWriter(System.out));
            
            String line = null;
            while((line=bufr.readLine())!=null)
            {
                if("over".equals(line))
                {
                    break;
                }
                bufw.write(line);
                bufw.newLine();
                bufw.flush();
            }
            bufr.close();
            bufw.close();

        }
        
}