java第十四次课后笔记

1.读取文件，用while实现。

import java.io.File;

import java.io.FileInputStream;

import java.io.IOException;

public class Test {

       publicstatic void main(String[] args) throws IOException {

      

              Fileff=new File("d:\\a.txt");

              FileInputStreamin=new FileInputStream(ff);

              byte[]b=new byte[3];

              intlen=0;

              while((len=in.read(b))!=-1){

                     System.out.print(newString(b,0,len).trim());

              }

               in.close();

              }

}

2.读取文件，用do{}while();实现

import java.io.File;

import java.io.FileInputStream;

import java.io.IOException;

public class Test {

       publicstatic void main(String[] args) throws IOException {

      

              Fileff=new File("d:\\a.txt");

              FileInputStreamin=new FileInputStream(ff);

              byte[]b=new byte[3];

              intc=0;

       do{

          System.out.print(new String(b,0,c).trim());

          c=in.year(b);

}while(c!=-1);

               in.close();

              }

}

 

3. 文件拷贝

import java.io.*;

import java.io.FileOutputStream;

 

public class Copy {

 public static void main(String[] args) throws Exception {

       FileInputStreamin=new FileInputStream("d:\\1.zip");

       FileOutputStreamout=new FileOutputStream("d:\\1.1.zip");

      

       byte[]b=new byte[1024*1024*3];

       intlen=0;

       longsize=0;

       while((len=in.read(b))!=-1){

              size+=len;

              System.out.println(size/1024/1024+"M");

              out.write(b,0,len);

       }

       in.close();

       out.close();

}

}

 

4.照片颜色变化

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.util.Date;

public class Test2 {

       publicstatic void write1(FileOutputStream out, int r, int g, int b)

                     throwsException {

              out.write(b);

              out.write(g);

              out.write(r);

       }

       publicstatic void out(int i) throws Exception {

              FileInputStreamin = new FileInputStream("D:\\2.bmp");

              FileOutputStreamout = new FileOutputStream("D:\\che\\"

                            +new Date().getTime() + ".bmp");

              byte[]b = new byte[54];

              in.read(b);

              out.write(b);

              while(true) {

                     intr1, g1, b1;

                     b1= in.read();

                     g1= in.read();

                     r1= in.read();

                     if(b1 == -1) {

                            break;

                     }

                     switch(i) {

                     case1:

                            write1(out,255, g1, b1);

                            break;

                     case2:

                            write1(out,r1, 255, b1);

                            break;

                     case3:

                            write1(out,r1, g1, 255);

                            break;

                     case4:

                            write1(out,r1, 255, 255);

                            break;

                     case5:

                            write1(out,255, g1, 255);

                            break;

                     case6:

                            write1(out,255, 255, b1);

                            break;

                     case7:

                            write1(out,0, 255, b1);

                            break;

                     case8:

                            write1(out,255, 0, b1);

                            break;

                     case9:

                            write1(out,0, g1, b1);

                            break;

                     case10:

                            write1(out,r1, 0, b1);

                            break;

                     case11:

                            write1(out,r1, g1, 0);

                            break;

                     }

              }

              out.close();

              in.close();

       }

       publicstatic void main(String[] args) throws Exception {

              out(1);

              out(2);

              out(3);

              out(4);

              out(5);

              out(6);

              out(7);

              out(8);

              out(9);

              out(10);

              out(11);  

       }

}

5.将黑色部分转化为白色

importjava.io.FileInputStream;

importjava.io.FileNotFoundException;

importjava.io.FileOutputStream;

importjava.io.IOException;

public class Test {

   

        publicstatic void write1(FileOutputStream out,int r,int g,int b) throws IOException{

            out.write(b);

            out.write(g);

            out.write(r);

        }

        publicstatic void main (String [] arge) throwsIOException{

            FileInputStream in=new FileInputStream("E:\\z.bmp");

            FileOutputStream out=newFileOutputStream("D:\\z.bmp");

            byte [] b=new byte[54];

            in.read(b);

            out.write(b);

            while(true){

                    int r1,g1,b1;

                    r1=in.read();

                    g1=in.read();

                    b1=in.read();

                    if(b1==-1){

                        break;

                    }

                    if(r1==0&&g1==0&&b1==0){

                       write1(out,255,255,255);  

                    }else{

                       write1(out,r1,g1,b1);}              

                }  

        }

    }

 

}