基于字符流读写文件

//写文件
package homework;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Scanner;

public class Wenjian1 {

    public static void main(String[] args) throws IOException {
        Scanner in=new Scanner(System.in);
        String pathname="d:/student1.txt";
        File f=new File(pathname);
        FileWriter fw=null;
        BufferedWriter bw=null;
        fw=new FileWriter(f);
        bw=new BufferedWriter(fw);
        bw.write("姓名\t数学\t物理\t化学\t总成绩");
        bw.newLine();
        String xm;
        int cj1,cj2,cj3,zcj;
        int yes=1;
        while(yes==1) {
            System.out.println("请依次输入 姓名 数学 物理 化学:");
            xm=in.next();
            cj1=in.nextInt();
            cj2=in.nextInt();
            cj3=in.nextInt();
            zcj=cj1+cj2+cj3;
            bw.write(xm+"\t"+cj1+"\t"+cj2+"\t"+cj3+"\t"+zcj);
            bw.newLine();
            System.out.println("继续添加学生吗?(1/0)");
            yes=in.nextInt();
        }
        bw.close();
        fw.close();
        in.close();
        System.out.println("运行结束");
    }

}

//读文件,将一个文本文件输出在屏幕上,在输出时将小写字母转换成大写字母
package homework;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;

public class Wenjian2 {

    public static void main(String[] args) throws IOException {
        File f = new File("d:/dssjava/abc.txt");
        if (!f.exists()) {
            System.out.println("文件不存在");
            System.exit(0);
        }
        FileReader fr = new FileReader(f);
        BufferedReader br = new BufferedReader(fr);
        String msg = br.readLine();
        while (msg != null) {
            String abc = msg.toUpperCase();
            System.out.println(abc);
            msg = br.readLine();
        }
        br.close();
        fr.close();
    }

}