day20

Day20

file类
创建一个文件/文件夹
删除一个文件/文件夹
获取文件 文件夹
判断文件或者文件夹
对文件进行遍历
获取文件大小

记住三个单词：
file：文件
directory： 目录 文件夹
path：路径

Demo01File

package demo01;

import java.io.File;
import java.io.IOException;

public class Demo01File {
public static void main(String[] args) {

	String pathSeparator=File.pathSeparator;
	System.out.println(pathSeparator);
	String separator=File.separator;
	System.out.println(separator);
	
	show12();
}
		private static void show12() {
			File f1= new File("D:\\rxp\\java\\20\\day-20\\hello.java");
			boolean b1=f1.delete();
			System.out.println(b1);
		
			File f2= new File("rxp\\1\\2\\33\\44");
			boolean b2=f2.delete();
			System.out.println(b2);
		}

		private static void show11() {
			
			File f1= new File("D:\\rxp\\java\\20\\day-20\\hello.java");
			boolean b1=f1.mkdir();
			System.out.println(b1);
			
			File f2= new File("D:\\rxp\\java\\20\\day-20\\1\\2\\33\\44\\hello.java");
			boolean b2=f2.mkdirs();
			System.out.println(b2);
		}

		private static void show10() throws IOException {
			File f1= new File("D:\\rxp\\java\\20\\day-20\\hello.java");
			boolean b1=f1.createNewFile();
			System.out.println(b1);
			
			File f2= new File("D:\\rxp\\java\\20\\day-20\\新建文件夹");
		
			boolean b2=f2.createNewFile();
			System.out.println(b2);
			
		}

		private static void show09() {
			File f1= new File("D:\\rxp\\java\\20\\day-20");
			if(f1.exists()) {
				System.out.println(f1.isDirectory());
				System.out.println(f1.isFile());
			}
			System.out.println("=====================");
			File f2= new File("D:\\rxp\\java\\20\\day-20\\classfive");
			if(f2.exists()) {
				System.out.println(f2.isDirectory());
				System.out.println(f2.isFile());
			}
			
			System.out.println("=====================");
			File f3= new File("D:\\rxp\\java\\20\\day-20\\classpath");
			if(f2.exists()) {
				System.out.println(f3.isDirectory());
				System.out.println(f3.isFile());
			}
		}
private static void show08() {
	File f1=new File("D:\\rxp\\java\\20\\day20_code");
	System.out.println(f1.exists());
	File f2=new File("D:\\rxp\\java\\20\\day20_code//classfive");
	System.out.println(f2.exists());
}


private static void show07() {
	File f1=new File("D:\\rxp\\java\\20\\day20_code");
	System.out.println(f1.length());
	File f2=new File("D:\\rxp\\java\\20\\day20_code\\classfive");
	System.out.println(f2.length());
	File f3=new File("D:\\rxp\\java\\20\\day20_code\\classpath");
	System.out.println(f3.length());
	File f4=new File("D:\\rxp\\java\\20\\day20_code\\hello.java");
	System.out.println(f4.length());
}

private static void show06() {
	File f1=new File("D:\\rxp\\java\\20\\day20_code\\hello.java");
	File f2=new File("D:\\\\rxp\\\\java\\\\20\\\\day20_code");
	
	System.out.println(f1.getName());
	System.out.println(f2.getName());
}

private static void show05() {
	File f1=new File("D:\\rxp\\java\\20\\day20_code\\hello.java");
	File f2=new File("a.txt");
	String path1=f1.getPath();
	System.out.println(path1);
	System.out.println(f2.getPath());
	System.out.println(f1);
	System.out.println(f1.toString());
}

private static void show04() {
	File f1=new File("D:\\rxp\\java\\test\\hello.java");
	String absolutepath1=f1.getAbsolutePath();
	System.out.println(absolutepath1);
	File f2=new File("hello.java");
	
	String absolutepath2=f2.getAbsolutePath();
	System.out.println(absolutepath2);
}

private static void show03() {
	File parent=new File("D:\\rxp\\java\\test");
	File f1=new File(parent,"hello.java");
	System.out.println(f1);
}

private static void show02(String parent, String child) {
	File f1=new File(parent,child);
	System.out.println(f1);
	
}

private static void show01() {
	File f1=new File("D:\\rxp\\java\\test");
	System.out.println(f1);
	File f2=new File("D:\\rxp\\java\\a.test");
	System.out.println(f2);
	File f3=new File("b.txt");
	System.out.println(f3);
}
}

Demo02OutputStream

package demo02;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.IOException;

public class Demo02OutputStream {
	public static void main(String[] args) throws IOException {
		FileOutputStream fos=new FileOutputStream("a.txt");
		 byte[] bytes= {65,66,67,68,69,70};
		 fos.write(bytes,2,3);
		 fos.close();
		
		
	}

}