类的继承，文件读写

package hh;
public class People {
 protected String name;
 protected int age=16;
 public String getName() {
  return name;
 }
 public void setName(String name) {
  this.name = name;
 }
 public void getAge() {
  return age;
 }
 public void setAge(int age) {
  this.age = age;
 }
 //父类的print方法
 public void print(){
  System.out.println(this.name);
  System.out.println(this.age);
 }
}

package hh;
//继承使用extends关键字，前边是子类，后边是父类，类的继承只能有一个父类
public class Student extends People {
 private String no;
 //子类的成员变量和父类的成员变量同名时父类的成员变量被覆盖
 protected int age = 20;
 public String getNo() {
  return no;
 }
 public void setNo(String no){
  this.no = no;
 }
 //重载：在同一个类里多个方法名字相同，参数不一样
 //重写：在子类和父类之间多个方法名相同，参数相同，并且返回值也相同
 //调用父类同名的方法，前加上super
 public void print(){
  super.print();
  System.out.println(this.no);
 }
}

package hh;
public class Test {
 public static void main(String[] args) {
  People dashu = new People();
  dashu.setName("dashu");
  dashu.setAge(16);
  //调用父类的print方法
  dashu.print();

  Student stu = new Student();
  stu.setName("hhhhh");
  stu.setAge(16);
  stu.setNo("1024");
  //子类对象的调用
  stu.print();
 }
}

package test2;

import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
public class text {
 public static void main(String[] args) {
  String filename = "c:/test/FileDemo.java";
  File f1=new File(filename);
  try{
   RandomAccessFile raf1=new RandomAccessFile(filename,"r");
   byte[] b = new byte[(int)f1.length()];
   StringBuffer sb = new StringBuffer();
   for(int i = 0;raf1.read(b)!=-1;i++){
     sb.append(new String(b,"utf-8"));
   }
   System.out.println(sb.reverse().toString());
   raf1.close();
 }catch(IOException e){
  e.printStackTrace();
 }
 }
}

public class text1 {

    public static void main(String[] args) {
        FileReader fr;
        BufferedReader br;
        File file = new File("c:/test/FileDemo.java");
        String str;
        int n = 0;
        try {
            fr = new FileReader(file);
            br = new BufferedReader(fr);
            while((str = br.readLine()) != null){
                n++;
                System.out.println(n + "." + str);
            }
        }catch(FileNotFoundException e){
            e.printStackTrace();
        }catch(IOException e){
            e.printStackTrace();
        }
    }
}

public class FileDemo {

    //创建一个文件夹
    public static void createFolder(String path){
        File folder=new File(path);
        if(folder.exists()){
            System.out.println("文件夹已存在！");
        }else{
            //不存在时去创建
            folder.mkdir();
        }
    }
    //创建一个文件
    public static void createFile(String path,String filename){
        File file=new File(path,filename);
        //文件判断是否已存在
        if(file.exists()){
            System.out.println("文件已存在！");
            System.out.println(file.length());
        }else{
            try{
                file.createNewFile();
            }catch(IOException e){
                System.out.println("文件创建失败！");
            }
        }
    }
    //写文件
    public static void write(String path,String filename){
        try{
            String str="0123456789/nac";
            String Upstr = str.toUpperCase();//
            byte b[]=Upstr.getBytes();//
            FileOutputStream fos=new FileOutputStream(new File(path,filename));
            fos.write(b);
            fos.close();
        }catch(FileNotFoundException e){
            System.out.println("文件不存在");
        }catch(IOException e){
            System.out.println("写文件失败");
        }
    }
    //读文件
    public static void read(String path,String filename){
        try{
            int length=0;
            String str="";
        
            byte buffer[]=new byte[10];
            FileInputStream fis=new FileInputStream(new File(path,filename));
            
            while((length=fis.read(buffer, 0, buffer.length)) !=-1){
                str+=new String (buffer, 0, length);
            }
            System.out.println(str);//
            fis.close();
        }catch(FileNotFoundException e){
            System.out.println("文件不存在");
        }catch(IOException e){
            e.printStackTrace();
        }
    }
//
    public static void FileReaderCopy(String src,String des){
        try{
        FileReader fr=new FileReader(src);
        FileWriter fw=new FileWriter(des);
        char c[]=new char[1024];
        int len=0;
        
        while((len=fr.read(c, 0, c.length)) != -1){
            fw.write(c, 0, c.length);
        }
        fw.close();
        fr.close();
    } catch(FileNotFoundException e){
        System.out.println("文件不存在");
    }catch(IOException e){
        System.out.println("读写失败");
    }
    }
    //
    public static void BufferedReaderCopy(String src,String des){
        try{
            BufferedReader br=new BufferedReader(new FileReader(src));
            BufferedWriter bw=new BufferedWriter(new FileWriter(des));
            String str="";
            while((str=br.readLine()) != null){
                String Upstr = str.toUpperCase();//加入大写的变换
                bw.write(Upstr);//
                bw.newLine();
            }
            bw.close();
            br.close();
        } catch(FileNotFoundException e){
            System.out.println("文件存在");
        }catch(IOException e){
            System.out.println("读写失败");
        }
        }
    //复制
    public static void copy(String src,String des){
        try{
            FileInputStream fis=new FileInputStream(src);
            FileOutputStream fos=new FileOutputStream(des);
            int c;
            while((c=fis.read()) != -1){
                fos.write(c);
            }
            fos.close();
            fis.close();
        }catch(FileNotFoundException e){
            System.out.println("文件不存在");
        }catch(IOException e){
            System.out.println("读写失败");
        }
    }
    //复制文件
    public static void copy1(String src,String des){
        try{
            FileInputStream fis=new FileInputStream(src);
            FileOutputStream fos=new FileOutputStream(des);
            int c;
            byte buff[]=new byte[1024];
            while((c=fis.read(buff,0,buff.length)) != -1){
                fos.write(buff,0,c);
            }
            fos.close();
            fis.close();
        }catch(FileNotFoundException e){
            System.out.println("文件不存在");
        }catch(IOException e){
            System.out.println("读写失败");
        }
    }
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        FileDemo.createFolder("c:/test");
        FileDemo.createFile("c:/test", "1.txt");
        FileDemo.write("c:/test", "1.txt");
        FileDemo.read("c:/test", "1.txt");
        FileDemo.read("c:/test", "FileDemo.java");
        FileDemo.BufferedReaderCopy("c:/test/FileDemo.java", "c:/test/FileDemo2.java");
        FileDemo.copy1("c:/test/1.mp3", "c:/test/2.mp3");
    }

}