package test;
import java.io.BufferedReader;
import java.io.BufferedWriter;
/**
- Related operations of documents include
- File directory create file create file write file read file rename etc
*/
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.OutputStreamWriter;
public class FileOperate {
//5. Delete directory
public static void delDir(String path){
File dir=new File(path);
if(dir.exists()){
//The list() method returns the file names of all files and directories in a directory, and the String array
//The listfields () method returns the absolute path of all files and directories in a directory, and the array of files
File[] tmp=dir.listFiles();
for(int i=0;i<tmp.length;i++){
if(tmp[i].isDirectory()){
delDir(path+"/"+tmp[i].getName());
}
else{
tmp[i].delete();
}
}
dir.delete();
}
}
//6. Delete files
public static void delFile(String path,String filename){
File file=new File(path+"/"+filename);
if(file.exists()&&file.isFile())
file.delete();
}
//7. File rename
public static void renameFile(String path,String oldname,String newname){
if(!oldname.equals(newname)){//If the new file name is different from the previous one, it is necessary to rename it
File oldfile=new File(path+"\\"+oldname+".txt");
File newfile=new File(path+"\\"+newname+".txt");
if(newfile.exists())//If there is already a file with the same name as the new file in this directory, renaming is not allowed
System.out.println(newname+"Already exists!");
else{
oldfile.renameTo(newfile);
}
}
}
public static void main(String[] args) throws IOException {
//1. Creation of directory
//Define file path
String basepath="D:\FileOperate";
File dir=new File(basepath);
//Judge if the directory (path) does not exist, create directory (path) dir.mkdir()
if(!dir.exists()){
dir.mkdir();
System.out.println("Folder created successfully!");
}
//Define file name
String fileName = "firstFile";
//Path the path to the text file you created
String path=basepath+"\\"+fileName+".txt";
//Create a directory where files are stored
File file=new File (path);
//Create file if file does not exist
if(!file.exists()){
try {
file.createNewFile();
} catch (IOException e) {
System.out.println(e.getMessage());
}
System.out.println("success create file,the file is"+path);
}
//3.1 FileWriter
String Data =" This content will append to the end of the file";
try {
//new FileWriter(file,true); in this way, the existing content and the new content attached to the end of the file will be preserved and will not be overwritten
FileWriter fileWriter=new FileWriter(path,true);
//\r\n implement line feed
fileWriter.write(Data+"\r\n Where to play today?\r\n");
//Refresh
fileWriter.flush();
//close resource
fileWriter.close();
System.out.println("Done");
} catch (IOException e) {
e.printStackTrace();
}
//3.2.1 BufferedWriter writing files
String Content="if you don't care,i will kill you";
try {
//Create a character buffer stream object
//BufferedWriter bw=new BufferedWriter(new FileWriter(path)); this will overwrite the previous content
//In this way, you can append the file content without overwriting it
BufferedWriter BW=new BufferedWriter(new OutputStreamWriter(new FileOutputStream(path,true)));
//System.out.println(new FileWriter(path));
//Write data
//bw.write(Content);
BW.write(Content);
//Line feed implementation in BufferedWriter, line feed can also be implemented
BW.newLine();
BW.write("weather\r\n");
BW.write("sunny");
//Refresh after entering data
BW.flush();
//close resource
//br.close();
BW.close();
System.out.println("OK!");
//3.2.2 (in IO operation, using BufferedReader and BufferedWriter will be more efficient)
BufferedReader br=new BufferedReader(new FileReader(file));
String temp=null;
StringBuffer sb=new StringBuffer();
temp=br.readLine();
while(temp!=null){
sb.append(temp+" ");
temp=br.readLine();
}
String output=sb.toString();
System.out.println(output);
} catch (IOException e) {
e.printStackTrace();
}
//3.3
//3.3.1FileOutputStream write file
FileOutputStream fop=null;
String content="This is to write a file with a file output stream";
try {
//Create a FileOutputStream.txt file
file=new File(basepath+"\\"+"FileOutputStream.txt");
//Create FileInputStream class object FileOutputStream(file,true) and add parameter true, the data added later will not overwrite the previous data
//FileOutputStream(file); this will overwrite the original data
fop=new FileOutputStream(file,true);
//If the file does not exist, create the file
if (!file.exists()) {
file.createNewFile();
}
//Convert content data to binary data and create byte array
byte[] contentInBytes=content.getBytes();
//Write array information to a file
fop.write(contentInBytes);
//Line wrap
fop.write("\r\n".getBytes());
//Refresh
fop.flush();
//Closed flow
fop.close();
System.out.println("FileOutputStream Done!");
//3.3.2 read file information
//Create FileInputStream class object
FileInputStream inputStream=new FileInputStream(file);
//Create byte array
byte[] readcontent=new byte[1024];
//Read information from file
int i=inputStream.read(readcontent);
//Information in the output file
System.out.println(new String(readcontent,0,i));
//Closed flow
inputStream.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
}finally{
try{
if(fop!=null){
fop.close();
}
}catch(IOException e){
e.printStackTrace();
}
}
//4. Catalog deletion
//To delete a directory by using the delete() method of the File class, you must ensure that there are no files or subdirectories in the directory
//Otherwise, the deletion fails, so in practice, we need to delete the directory
//, you must use recursion to delete all subdirectories and files under the directory, and then delete the directory.
//delDir(basepath); delete basepath directory
//delDir(basepath);
//File deletion
//delFile(basepath,"firstFile.txt");
//File rename
//renameFile(basepath, "firstfile", "file");
}
}