Java字节流 从文件输入输出到文件过程解析

ch = (char)System.in.read(); //读入一个字符，返回读到的字节的int表示方式,读到末尾返回-1

import java.io.*;public class 字节流的缓冲区 {  public static void main(String[] args) throws Exception {    FileInputStream in=new FileInputStream("E://photo//IMG.jpg");    //FileOutputStream中的文件不存在，将自动新建文件    OutputStream out=new FileOutputStream("E://test.jpg");    byte[] buff=new byte[1024];    int b;    long beginTime=System.currentTimeMillis();    while ((b=in.read(buff))!=-1) {      out.write(buff,0,b);    }    long endTime=System.currentTimeMillis();    System.out.println("运行时长为: "+(endTime-beginTime)+"毫秒");    in.close();    out.close();    System.out.println("正常运行！");  }}

//封装了FileOutputStream管道之后，三种函数参数//write(b) 写入一个b//write(byte[] b) 将字节数组全部写入//write(byte[] b,int off,int len) 例如write(byteTest,0,len)表示数组byteTest中从0开始长度为len的字节//一般都用第3个

import java.io.*;public class 字节缓冲流 {  public static void main(String[] args) throws Exception {    BufferedInputStream bis=new BufferedInputStream(new FileInputStream("E://photo//IMG.jpg"));    BufferedOutputStream bos=new BufferedOutputStream(new FileOutputStream("E://test.jpg"));    int len;    long begintime=System.currentTimeMillis();    while((len=bis.read())!=-1) {      bos.write(len);    }    long endtime=System.currentTimeMillis();    System.out.println("运行时间为："+(endtime-begintime)+"毫秒");    bis.close();    bos.close();    System.out.println("正常运行");  }}

import java.io.*;public class outFile {  public static void main(String[] args) throws Exception {    FileOutputStream out=new FileOutputStream("example.txt");    String str="测试";    byte[] b=str.getBytes();    for(int i=0;i<b.length;i++) {      out.write(b[i]);    }    out.close();    System.out.println("输出成功");  }}

FileOutputStream out=new FileOutputStream("example.txt",true);