Java零基础入门之IO流详解（一）

//指明详细的路径以及文件名，请注意双斜线或用反斜杠
File f1 = new File("E:/IO.txt");//表示IO.txt文件
//指明详细的路径以及目录名，请注意双斜线
File f2 = new File("E:\\Java");//表示Java目录
//创建多级目录(文件夹)
        File f =new File("E:\\package\\package1\\package2\\package3");
        f.mkdirs();

 public static void main(String[] args) {
 
        File f1 = new File("E:/IO.txt");
        //判断该文件是否存在
        System.out.println(f1.canExecute());//true
        //是否可读
        System.out.println(f1.canRead());//true
        //是否可写
        System.out.println(f1.canWrite());//true
        //得到完整地址
        System.out.println(f1.getAbsolutePath());//E:\IO.txt
        //得到文件名
        System.out.println(f1.getName());//IO.txt
        //得到目录
        System.out.println(f1.getParent());//E:\
        //判断是否为目录
        System.out.println(f1.isDirectory());//false
        //是否为隐藏文件
        System.out.println(f1.isHidden());//false
        //文件创建时间
        System.out.println(f1.lastModified());//1710659923057
        System.out.println(new Date(1710639860957L));//[Sun Mar 17 09:41:02 CST 2024]
        //文件长度(字节)
        System.out.println(f1.length());//14
    }

 public static void main(String[] args) throws IOException {
       
        FileInputStream inputStream1 =new FileInputStream("D:/ddd.docx");//输入流
        FileOutputStream outputStream1 =new FileOutputStream("E:/eee.docx");//输出流
        int a =0 ;
        while((a=inputStream1.read())!=-1){//只要a!=-1说明还未读完
            outputStream1.write(a);//写内容(以字节为单位)
        }
        //关闭通道,否则文件一直处于打开(占用)状态
        inputStream1.close();
        outputStream1.close();
    }

public static void main(String[] args) throws IOException {
        FileInputStream inputStream =new FileInputStream("D:/demo1.txt");
        FileOutputStream outputStream=new FileOutputStream("E:/IO.txt");
        byte[] bytes =new byte[10];
        //read(bytes) 一次读byte数组长度个字节,文件内容读取完后返回-1
        //size:每次实际往数组中装入的元素的个数
 
        int size =0;
        while((size=inputStream.read(bytes))!=-1){
        //一次向外写出一个byte数组长度个字节内容,从指定位置开始写，写size个
            outputStream.write(bytes,0,size);
        }
        inputStream.close();
        outputStream.close();
    }

 public static void main(String[] args) throws IOException {
        FileInputStream inputStream = new FileInputStream("D:/demo1.txt");
        //封装的是一个节点流对象，可以提供缓冲功能，称为处理流/包装流
        BufferedInputStream bufferedInputStream =new BufferedInputStream(inputStream,20);
        FileOutputStream outputStream =new FileOutputStream("E:/IO.txt");
        BufferedOutputStream bufferedOutputStream =new BufferedOutputStream(outputStream,20);
 
        int size =0;
        byte[] bytes =new byte[10];
        while ((size=bufferedInputStream.read(bytes))!=-1){
            bufferedOutputStream.write(bytes,0,size);
        }
        bufferedInputStream.close();
        bufferedOutputStream.close();
    }