Java File Operations

CreateTempFile&Modifiedtime.java

import java.io.*;
 
public class Main {
    public static void main(String[] args) throws Exception {
        File temp = File.createTempFile("tmp", ".txt");
        System.out.println("File Path: "+temp.getAbsolutePath());
      
        Date filetime = new Date(temp.lastModified());
        System.out.println(filetime.toString());
        System.out.println(fileToChange.setLastModified(System.currentTimeMillis()));
        
        temp.deleteOnExit();
    }
}

FileRename.java

import java.io.File;
import java.io.IOException;
 
public class RunoobTest {
    public static void main(String[] args) throws IOException {
        File oldName = new File("./test.txt");
        File newName = new File("./test-2.txt");
        if (newName.exists()) {  
            throw new java.io.IOException("file exists");
        }
        if(oldName.renameTo(newName)) {
            System.out.println("rename done");
        } else {
            System.out.println("Error");
        }
    }
}

FileWrite&Copy&Read&Delete.java

import java.io.*;
 
public class Main {
    public static void main(String[] args)  {
      //write
        try {
            BufferedWriter out = new BufferedWriter(new FileWriter("srcfile"));
            out.write("123");
            out.close();
        } catch (IOException e) {
        }
      //copy
        InputStream in = new FileInputStream(new File("srcfile"));
        OutputStream out = new FileOutputStream
        (new File("destnfile"));
        byte[] buf = new byte[1024];
        int len;
        while ((len = in.read(buf)) > 0) { //in.read() is important
            out.write(buf, 0, len);
        }
        in.close();
        out.close();
     
      //read
        try {
            BufferedReader in = new BufferedReader(new FileReader("destnfile"));
            String str;
            while ((str = in.readLine()) != null) {
                System.out.println(str);
            }
            System.out.println(str);
        } catch (IOException e) {
        }
      
      //delete
        try{
            File file = new File("c:\\test.txt");
            if(file.delete()){
                System.out.println(file.getName() + " has been deleted！");
            }else{
                System.out.println("delete failed！");
            }
        }catch(Exception e){
            e.printStackTrace();
        }
    }
    }
}

GetFileSize&SetReadOnly.java

import java.io.File

public static long getFileSize(String filename) {
        File file = new File(filename);
        if (!file.exists() || !file.isFile()) {
            System.out.println("File is not exist!");
            return -1;
        }
        System.out.println(file.setReadOnly());
        System.out.println(file.canWrite());
        return file.length();
    }