io流

io流

   public void created1()  {
       String filepath="E:\\news.txt";
       //在内存里开辟空间
        File file = new File(filepath);
        try {
        //将内存传递到文件中
            file.createNewFile();
            System.out.println("ok");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

 //输出流
 @Test
    public void writefile() throws IOException {
    //得到路径
         String filepath="e:\\a.txt";
        FileOutputStream fileOutputStream=null;
        创建对象
        fileOutputStream = new FileOutputStream(filepath);
        String str="hello world";
        //将字符串str给字节数组，并创建文件
        fileOutputStream.write(str.getBytes());

    }

 public void readFile1() throws IOException {
 //得到路径
        String filepath=("e:\\hello.txt");
        int readdate=0;
        int  readlen=0;
        byte[] buff=new byte[8];
        //创建对象
        File  file = new File(filepath);
        //将对象创建到文件中
        file.createNewFile();
        //创建对象来读取文件
        FileInputStream fileInputStream=new FileInputStream(filepath);
while((readlen=fileInputStream.read(buff))!=-1){
//read读取文件
    System.out.print(new String(buff,0,readlen));

}

fileInputStream.close();
    }

 //文件拷贝
 public static void main(String[] args) throws IOException {
        String filepath1="E:\\\\2.jpg";
        String filepath2="E:\\\\3.jpg";

        FileInputStream fileInputStream=null;
        FileOutputStream fileOutputStream=null;
        //创建对象用来输入
        fileInputStream=new FileInputStream(filepath1);
        //创建对象用来输出
        fileOutputStream=new FileOutputStream(filepath2);
        byte[] buf=new byte[1024];
        int readln=0;
        //读取文件
        while ((readln=fileInputStream.read(buf))!=-1){
        //write创建文件，并输出
            fileOutputStream.write(buf,0,readln);
        }
        System.out.println("ok");
        fileInputStream.close();
        fileOutputStream.close();
    }

package Text;

import java.io.*;

public class Demo1 {
    public static void main(String[] args) throws IOException {
        String filepath = "e:\\mytemp";
        //创建对象
        File file = new File(filepath);
        当文件不存在创建目录
        if (file.exists()) {
            System.out.println("目录创建失败");
        } else {
            //创建目录
            file.mkdir();
            System.out.println("目录创建成功");
        }
        String sonpath = "e:\\mytemp\\hello.txt";
        //创建对象，当文件不存在创建文件
        File file1 = new File(sonpath);
        if (!file1.exists()) {
            //创建文件
            file1.createNewFile();
            //通过buff创建filewrite对象再sonpath路径下
            BufferedWriter bw = new BufferedWriter(new FileWriter(sonpath));
            //输出字符
        bw.write("hello world");
        //关闭
        bw.close();

        } else {
            System.out.println("文件创建成功");

    }
    }
}

package Text;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;

public class Demo2 {
    public static void main(String[] args) throws IOException {
        String filepath="e:/c.txt";
        String line="";
        int count=0;
        //buffread通过fileread方法在filepath路径里创建对象
        BufferedReader br = new BufferedReader(new FileReader(filepath));
       // 通过循环读取字符，readline为换行
        while ((line=br.readLine())!=null){
            System.out.println(++count+line);
        }
br.close();
    }
}

package Text;

import java.io.*;

public class Demo2 {
    public static void main(String[] args) throws IOException {
        String filepath="e:/c.txt";
        String line="";
        int count=0;
        //将字节流变成转换流最后再变成处理流。处理流最好，因为处理流有许多节点流的方式，最后将文件以gbk编码方式输出
        BufferedReader gbk = new BufferedReader(new InputStreamReader
                (new FileInputStream(filepath), "gbk"));
//        BufferedReader br = new BufferedReader(new FileReader(filepath));
        while ((line=gbk.readLine())!=null){
            System.out.println(++count+line);
        }
gbk.close();
    }
}

package Text;

import java.io.*;
import java.util.Properties;

public class Demo4 {
    public static void main(String[] args) throws IOException {

        Properties properties = new Properties();
        properties.load(new FileReader("src\\dog.properties"));
        //获得name属性
        String  name = properties.get("name")+"";//object装换成string
        //获得age属性
        int age = Integer.parseInt(properties.get("age")+"");//object装换成int
        //获得color属性
        String color = properties.get("color")+"";//object装换成string
        Dog dog = new Dog(name,age,color);
//        properties.list(System.out);
        System.out.println(dog);
        String filepath="e:\\dog2.dat";
        //object创建对象通过fileout创建在filepath地址里
        ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(filepath));
        //将dog的属性输出通过writeobject
        oos.writeObject(dog);
        oos.close();
    }
}
class Dog implements Serializable{
private String name;
private int age;
private String color;

    public Dog(String name, int age, String color) {
        this.name = name;
        this.age = age;
        this.color = color;
    }

    @Override
    public String toString() {
        return "Dog{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", color='" + color + '\'' +
                '}';
    }
}