1-java中的IO操作

1.使用字节流写、读、复制数据

package com.example;

import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.UnsupportedEncodingException;

public class MyClass {
    public static void main(String []args){
        try {
            FileOutputStream fos = new FileOutputStream("test2.txt");

            String str = "hello";
            byte fosByte[] = str.getBytes("UTF-8");
            fos.write(fosByte);

            fos.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }


    }
}

package com.example;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

public class MyClass {
    public static void main(String []args){
        try {
            FileInputStream fis = new FileInputStream("test1.txt");

            byte fisByte[] = new byte[20];
           // fis.read(fisByte);
            int l = 0;
            while ((l =fis.read(fisByte))!= -1){
                String str = new String(fisByte,"UTF-8");
                System.out.println(str);
            }


            fis.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }


    }
}

package com.example;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class MyClass {
    public static void main(String []args){
        FileInputStream fis = null;
        try {
            fis = new FileInputStream("test.gif");
            FileOutputStream fos = new FileOutputStream("test2.gif");

            byte fisByte[] = new byte[50];
            while (fis.read(fisByte) != -1){
                fos.write(fisByte);
            }

            fos.close();
            fis.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
}

2.使用带缓冲的字节流写、读、复制文件

package com.example;

import java.io.BufferedOutputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.UnsupportedEncodingException;

public class MyClass {
    public static void main(String []args){

        try {
            FileOutputStream fos = new FileOutputStream("test4.txt");
            BufferedOutputStream bos = new BufferedOutputStream(fos);

            String str = "hello wangyu";
            byte b[] = str.getBytes("UTF-8");
            bos.write(b);

            bos.close();
            fos.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }


    }
}

package com.example;

import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

public class MyClass {
    public static void main(String []args){
        try {
            FileInputStream fis = new FileInputStream("test3.txt");
            BufferedInputStream bis = new BufferedInputStream(fis);

            byte b[] = new byte[7];
            bis.read(b);
            String str = new String(b,"UTF-8");

            System.out.println(str);
            bis.close();
            fis.close();

        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
}

package com.example;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class MyClass {
    public static void main(String []args){
        try {
            FileInputStream fis = new FileInputStream("test.gif");
            BufferedInputStream bis = new BufferedInputStream(fis);
            FileOutputStream fos = new FileOutputStream("test3.gif");
            BufferedOutputStream bos = new BufferedOutputStream(fos);

            byte b[] = new byte[100];
            while (bis.read(b) != -1 ){
                bos.write(b);
            }

            bos.close();
            fos.close();
            bis.close();
            fis.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
}

3.使用字符流写、读、复制数据

package com.example;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

public class MyClass {
    public static void main(String []args){
        try {
            FileOutputStream fos = new FileOutputStream("test6.txt");
            OutputStreamWriter osw = new OutputStreamWriter(fos,"UTF-8");
            FileInputStream fis = new FileInputStream("test5.txt");
            InputStreamReader isr = new InputStreamReader(fis,"UTF-8");



            char c[] = new char[10];
            int l = 0;
            while ((l = isr.read(c)) != -1){
                osw.write(c,0,l);
            }

            osw.close();
            fos.close();
            isr.close();
            fis.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
}

4.使用带缓冲的字符流写、读、复制数据

package com.example;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;

public class MyClass {
    public static void main(String []args){
        try {
            FileInputStream fis = new FileInputStream("test6.txt");
            InputStreamReader isr = new InputStreamReader(fis,"UTF-8");
            BufferedReader br = new BufferedReader(isr);

            FileOutputStream fos = new FileOutputStream("test7.txt");
            OutputStreamWriter osw = new OutputStreamWriter(fos);
            BufferedWriter bw = new BufferedWriter(osw);

            String str = new String();

            while ((str = br.readLine()) != null){
                //System.out.println(str);
                bw.write(str);
            }

            bw.close();
            osw.close();
            fos.close();
            br.close();
            isr.close();
            fis.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}