Java IO流

public static void main(String[] args) throws IOException{
    File file = new File("d:/python");
    file.mkdir();   //文件夹不存在就建立该文件夹
    /*
    mkdir()与mkdirs()区别是前者建立不存在的文件夹必须要求
    父路径存在，比如“d:/java/app”要建立app文件夹前提是jav
    a必须存在，否则报错；而mkdirs()方法不用。*/
    if(file.exists()&&file.isDirectory()){
        System.out.println("python存在");
        File file1 = new File("d:/python/spider.txt");
        File file2 = new File("d:/python/user.txt");
        file1.createNewFile();
        file2.createNewFile();
        File[] files = file.listFiles();
        for(File f:files){
            System.out.println("python目录下的文件名："+f.get
            Name());
            System.out.println("python目录下文件的绝对路径
            ："+f.getAbsolutePath());
        }
        else{
            System.out.println("python目录不存在");
        }
    }

public static void main(Strin[] args)throws Exception{
    //必须处理IO流的异常，不然报错！
    FileOutputStream wos = new FileOutputStream("D:/abc.txt");
    //如果没有找到文件，会自动创建
    String content = "I love java";
    byte[] array = content.getBytes();
    //字符流以字节为单位写入，将String转换为byte型
    try{
        wos.write(array);
    }
    catch(IOException e){
        System.out.println(e);
    }
    FileInputStream ios = new FileInputStream("D:/abc.txt");
    try{
        int len = 0;
        byte[] array1 = new byte[2];
        //每次读取两个字节
        while((len=ios.read(array1)!=-1){
            System.out.println(array1);
            //依次输出"[B@15db9742"
        }
    }
    catch(IOException e){
        System.out.println(e);
    }
}

String s = "你好";
//String -- byte[]
byte[] bys = s.getBytes(); // [-60, -29, -70, -61]
byte[] bys = s.getBytes("GBK");// [-60, -29, -70, -61]
byte[] bys = s.getBytes("UTF-8");// [-28, -67, -96, -27, -91, -67]

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

public class io {
    public static void main(String args[]) throws IOException{
        OutputStreamWriter ows = new OutputStreamWriter(new 
                FileOutputStream("D:/a.txt"));
        String s = "Troye Sivan";
        ows.write(s);
        ows.close();
        //操作同一文件必须先关闭输出流
        InputStreamReader iws = new InputStreamReader(new 
                FileInputStream("D:/a.txt"));
        char[] r = new char[1];
        int len=0;
        while((len=iws.read(r))!=-1) {
            System.out.println(r);
        }
        iws.close();
    }
}

import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class io1 {
    public static void main(String[] args) throws IOException{
        FileReader fr = new FileReader("D:/a.txt");
        FileWriter fw = new FileWriter("D:/abc.txt");
        char[] ch = new char[2];
        int len=0;
        while((len=fr.read(ch))!=-1) {
            fw.write(ch,0,len);
            fw.flush();
        }
        fr.close();
        fw.close();
    }
}        

import java.io.FileWriter;
import java.io.FileReader;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;

public class io_buffer {
    public static void main(String[] args) throws IOException{
        BufferedWriter bw = new BufferedWriter(new FileWriter("D:/abc.txt"));
        //BufferedWriter bw = new BufferedWriter(new
        //      OutputStreamWriter(new FileOutputStream("D:/abc.txt")));
        bw.write("ZAYN");
        bw.write("MALIK");
        bw.write("LET ME");
        bw.flush();
        bw.close();
        
        BufferedReader br = new BufferedReader(new FileReader("D:/abc.txt"));
        //BufferedReader br = new BufferedReader(new 
        //      InputStreamReader(new FileInputStream("D:/abc.txt"));
        char[] ch = new char[2];
        int len=0;
        while((len=br.read(ch))!=-1) {
            System.out.println(new String(ch,0,len));
        }
        br.close();
    }
}