Java学习之IO字节流

 字节流分为FileInputStream 和FileOutputStream

package com.io;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
/**
 * 文件字节流的读取
 * @author ganhang
 *
 */
public class FileInputStreamDemo {
    public static void main(String[] args) {
        File file=new File("1.txt");
        try {
            InputStream is=new FileInputStream(file);
            byte [] b= new byte[10];
            int len=-1;
            StringBuilder sb=new StringBuilder();//存读取的数据
            while((len=is.read(b))!=-1){
                sb.append(new String(b,0,len));
            }
            is.close();
            System.out.println(sb);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        
    }
}

package com.io;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
/**
 * 文件字节流的写入
 * @author ganhang
 *
 */
public class FileOutputStreamDemo {
    public static void main(String[] args) {
        File file = new File("1.txt");
        if (!file.exists()) {
            try {
                file.createNewFile();//没有则创建文件
            } catch (IOException e) {
                e.printStackTrace();
            }
        } else {
            try {
                OutputStream fos = new FileOutputStream(file, true);//文件末尾添加，不是覆盖
                byte[] info = "hello,world".getBytes();
                fos.write(info);
                fos.close();
                System.out.println("写入成功！");
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}