Wanted to know how to read the same Excel file in java using multi-thread. I tried reading the Excel file using XSSFWorkbook, but when the initialization step is executed the program is termination without even entering to catch or finally block using testNG framework
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.testng.annotations.BeforeSuite;
import org.testng.annotations.Parameters;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
public class MultiThread implements Runnable {
#BeforeSuite
#Parameters({"masterFileName"})
public void threadExm (String masterFileName) {
Thread guruThread1 = new Thread("Test1");
Thread guruThread2 = new Thread("Test2");
guruThread1.start();
guruThread2.start();
System.out.println("Thread names are following:");
System.out.println(guruThread1.getName());
System.out.println(guruThread2.getName());
}
#Override
public void run() {
try {
String excelFilePath = System.getProperty("user.dir") + "/inputfiles/Master.xlsx";
FileInputStream inputStream;
inputStream = new FileInputStream(new File(excelFilePath));
XSSFWorkbook wb = new XSSFWorkbook(inputStream);
test(wb);
} catch (Exception e) {
e.printStackTrace();
}
}
public void test(XSSFWorkbook wb){
System.out.println(wb.getSheet("Sheet1").getLastRowNum());
}
}
Related
Let's say I have theese words in a text file
Dictionary.txt
artificial
intelligence
abbreviation
hybrid
hysteresis
illuminance
identity
inaccuracy
impedance
impenetrable
imperfection
impossible
independent
How can I make each word a different object and print them on the console?
You can simple use Scanner.nextLine(); function.
Here is the following code which can help
also import the libraries
import java.util.Scanner;
import java.io.File;
import java.util.Arrays;
Use following code:-
String []words = new String[1];
try{
File file = new File("/path/to/Dictionary.txt");
Scanner scan = new Scanner(file);
int i=0;
while(scan.hasNextLine()){
words[i]=scan.nextLine();
i++;
words = Arrays.copyOf(words,words.legnth+1); // Increasing legnth of array with 1
}
}
catch(Exception e){
System.out.println(e);
}
You must go and research on Scanner class
This is a very simple solution using Files:
package org.kodejava.io;
import java.net.URI;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.List;
import java.util.Objects;
public class ReadFileAsListDemo {
public static void main(String[] args) {
ReadFileAsListDemo demo = new ReadFileAsListDemo();
demo.readFileAsList();
}
private void readFileAsList() {
String fileName = "Dictionary.txt";
try {
URI uri = Objects.requireNonNull(this.getClass().getResource(fileName)).toURI();
List<String> lines = Files.readAllLines(Paths.get(uri),
Charset.defaultCharset());
for (String line : lines) {
System.out.println(line);
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
Source: https://kodejava.org/how-do-i-read-all-lines-from-a-file/
This is another neat solution using buffered reader:
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* BufferedReader and Scanner can be used to read
line by line from any File or
* console in Java.
* This Java program
demonstrate line by line reading using BufferedReader in Java
*
* #author Javin Paul
*/
public class BufferedReaderExample {
public static void main(String args[]) {
//reading file line by line in Java using BufferedReader
FileInputStream fis = null;
BufferedReader reader = null;
try {
fis = new FileInputStream("C:/sample.txt");
reader = new BufferedReader(new InputStreamReader(fis));
System.out.println("Reading
File line by line using BufferedReader");
String line = reader.readLine();
while(line != null){
System.out.println(line);
line = reader.readLine();
}
} catch (FileNotFoundException ex) {
Logger.getLogger(BufferedReaderExample.class.getName()).log(Level.SEVERE, null, ex);
} catch (IOException ex) {
Logger.getLogger(BufferedReaderExample.class.getName()).log(Level.SEVERE, null, ex);
} finally {
try {
reader.close();
fis.close();
} catch (IOException ex) {
Logger.getLogger(BufferedReaderExample.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
Source: https://javarevisited.blogspot.com/2012/07/read-file-line-by-line-java-example-scanner.html#axzz7lrQcYlyy
These are all good answers. The OP didn't state what release of Java they require, but in modern Java I'd just use:
import java.nio.file.*;
public class x {
public static void main(String[] args) throws java.io.IOException {
Files.lines(Path.of("/path/to/Dictionary.txt")).forEach(System.out::println);
}
}
I am a beginner in Java and trying to learn the basics of FileInputStream and FileOutputStream. I was able to successfully write the data to the file but unable to read it. Here is my code. Could you please let me know, if I am missing something to read the data.
Application.java
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
public class Application {
public static void main(String[] args) throws FileNotFoundException {
try(FileOutputStream fs = new FileOutputStream("testdata.txt")){
ObjectOutputStream os = new ObjectOutputStream(fs);
MathematicalOperation mo = new MathematicalOperation();
os.writeObject(mo);
os.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
ReadingFile.Java
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.ObjectInputStream;
public class ReadDataFromFile {
public static void main(String[] args) throws FileNotFoundException{
try(FileInputStream fi = new FileInputStream("testdata.txt")){
ObjectInputStream oi = new ObjectInputStream(fi);
MathematicalOperation mo= (MathematicalOperation) oi.readObject();
System.out.println(mo);
oi.close();
} catch (IOException | ClassNotFoundException e) {
e.printStackTrace();
}
}
}
If you're trying to read the content of the .txt file, just use FileInputStream class.
Also, it would be of great help if you coul
While writing to the file "testdata.txt" you are passing object of MathematicalOperation class, you can set values of the class members before writing file (e.g. mo.setXXX()) and when you are reading that object from text file you can get those values using the return object of MathematicalOperation (e.g. mo.getXXX()) and before printing the object please override toString() method in your MathematicalOperation class to display the correct values of all fields of the class.
I am trying to append text to a text file on the Google Drive. But when I write, it whole file is overwritten. Why can't I just add the text in the end of the file?
DriveFile file = Drive.DriveApi.getFile(mGoogleApiClient, id);
file.open(mGoogleApiClient, DriveFile.MODE_WRITE_ONLY, null).setResultCallback(new ResultCallback<DriveApi.DriveContentsResult>() {
#Override
public void onResult(DriveApi.DriveContentsResult driveContentsResult) {
msg.Log("ContentsOpenedCallBack");
if (!driveContentsResult.getStatus().isSuccess()) {
Log.i("Tag", "On Connected Error");
return;
}
final DriveContents driveContents = driveContentsResult.getDriveContents();
try {
msg.Log("onWrite");
OutputStream outputStream = driveContents.getOutputStream();
Writer writer = new OutputStreamWriter(outputStream);
writer.append(et.getText().toString());
writer.close();
driveContents.commit(mGoogleApiClient, null);
} catch (IOException e) {
e.printStackTrace();
}
}
});
Finally I've found the answer to append the text on the drive document.
DriveContents contents = driveContentsResult.getDriveContents();
try {
String input = et.getText().toString();
ParcelFileDescriptor parcelFileDescriptor = contents.getParcelFileDescriptor();
FileInputStream fileInputStream = new FileInputStream(parcelFileDescriptor
.getFileDescriptor());
// Read to the end of the file.
fileInputStream.read(new byte[fileInputStream.available()]);
// Append to the file.
FileOutputStream fileOutputStream = new FileOutputStream(parcelFileDescriptor
.getFileDescriptor());
Writer writer = new OutputStreamWriter(fileOutputStream);
writer.write("\n"+input);
writer.close();
driveContentsResult.getDriveContents().commit(mGoogleApiClient, null);
} catch (IOException e) {
e.printStackTrace();
}
SO
The reason is that commit's default resolution strategy is to overwrite existing files. Check the API docs and see if there is a way to append changes.
For anyone facing this problem in 2017 :
Google has some methods to append data Here's a link!
Though copying the method from google didn't worked entirely for me , so here is the class which would append data : ( Please note this is a modified version of this code link )
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import android.content.Context;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.os.ParcelFileDescriptor;
import android.preference.PreferenceManager;
import android.util.Log;
import com.google.android.gms.common.api.Result;
import com.google.android.gms.common.api.ResultCallback;
import com.google.android.gms.drive.Drive;
import com.google.android.gms.drive.DriveApi.DriveContentsResult;
import com.google.android.gms.drive.DriveApi.DriveIdResult;
import com.google.android.gms.drive.DriveContents;
import com.google.android.gms.drive.DriveFile;
import com.google.android.gms.drive.DriveId;
/**
* An activity to illustrate how to edit contents of a Drive file.
*/
public class EditContentsActivity extends BaseDemoActivity {
private static final String TAG = "EditContentsActivity";
#Override
public void onConnected(Bundle connectionHint) {
super.onConnected(connectionHint);
final ResultCallback<DriveIdResult> idCallback = new ResultCallback<DriveIdResult>() {
#Override
public void onResult(DriveIdResult result) {
if (!result.getStatus().isSuccess()) {
showMessage("Cannot find DriveId. Are you authorized to view this file?");
return;
}
DriveId driveId = result.getDriveId();
DriveFile file = driveId.asDriveFile();
new EditContentsAsyncTask(EditContentsActivity.this).execute(file);
}
};
SharedPreferences sp= PreferenceManager.getDefaultSharedPreferences(EditContentsActivity.this);
Drive.DriveApi.fetchDriveId(getGoogleApiClient(), EXISTING_FILE_ID)
.setResultCallback(idCallback);
}
public class EditContentsAsyncTask extends ApiClientAsyncTask<DriveFile, Void, Boolean> {
public EditContentsAsyncTask(Context context) {
super(context);
}
#Override
protected Boolean doInBackgroundConnected(DriveFile... args) {
DriveFile file = args[0];
SharedPreferences sp=PreferenceManager.getDefaultSharedPreferences(EditContentsActivity.this);
System.out.println("0"+sp.getString("drive_id","1"));
DriveContentsResult driveContentsResult=file.open(getGoogleApiClient(), DriveFile.MODE_READ_WRITE, null).await();
System.out.println("1");
if (!driveContentsResult.getStatus().isSuccess()) {
return false;
}
DriveContents driveContents = driveContentsResult.getDriveContents();
try {
System.out.println("2");
ParcelFileDescriptor parcelFileDescriptor = driveContents.getParcelFileDescriptor();
FileInputStream fileInputStream = new FileInputStream(parcelFileDescriptor
.getFileDescriptor());
// Read to the end of the file.
fileInputStream.read(new byte[fileInputStream.available()]);
System.out.println("3");
// Append to the file.
FileOutputStream fileOutputStream = new FileOutputStream(parcelFileDescriptor
.getFileDescriptor());
Writer writer = new OutputStreamWriter(fileOutputStream);
writer.write("hello world");
writer.close();
System.out.println("4");
driveContents.commit(getGoogleApiClient(), null).await();
return true;
} catch (IOException e) {
e.printStackTrace();
}
return false;
};
#Override
protected void onPostExecute(Boolean result) {
if (!result) {
showMessage("Error while editing contents");
return;
}
showMessage("Successfully edited contents");
}
}
}
Existing_File_id is the resource id. Here is one link if you need resource id a link
I want to open, read, and edit file from my desktop. I am using Ideone online compiler. How do I read the file? I tried the following code:
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
class demo
{
public static void main(String[] args)
{
System.out.println("Hello World!");
File file = new File("C:/Users/psanghavi/Desktop/admin_confirmation_original.txt");
if (!file.exists())
{
System.out.println("does not exist.");
return;
}
if (!(file.isFile() && file.canRead()))
{
System.out.println(file.getName() + " cannot be read from.");
return;
}
try
{
FileInputStream fis = new FileInputStream(file);
char current;
while (fis.available() > 0)
{
current = (char) fis.read();
System.out.print(current);
}
}
catch (IOException e)
{
e.printStackTrace();
}
}
}
My desktop has file named: admin_confirmation_original.txt
Currently, No. About the limit, Idebone FAQ say about this:
Can I write or read files in my program? - No
Can I access the network from my program? - No
You can learn more about many Ideone restricted rule at FAQ.
Ideoone doesn't support reading local files.
This is not an answer to your question, but wrt to the comments
if you want to read files hosted, you could access them using URL class.
import java.net.MalformedURLException;
import java.net.URL;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.InputStreamReader;
class Demo {
public static void main(String[] args) throws IOException {
try {
final URL url = new URL("http://www.google.co.in/robots.txt");
//URL url = new URL("http://74.125.236.52/robots.txt");
BufferedReader in = new BufferedReader(
new InputStreamReader(url.openStream()));
String str;
while (in.readLine() != null) {
str = in.readLine();
System.out.println(str);
}
}
catch (MalformedURLException e) {
e.printStackTrace();
}
}
}
I have not tried it on file hosting sites.There are a lot of free file hostings available just google it.
import java.io.FileOutputStream;
import java.io.File;
public class AppendBinaryFile
{
public static void main (String[] args)
{
FileOutputStream toFile = null;
try
{
toFile = new FileOutputStream(new File("numbers.dat"), true);
toFile.write(15);
toFile.write(30);
toFile.close();
}
catch (Exception e)
{
}
}
}
I run another program to get the data from a binary file after running the program but data in the binary file does not change. What is wrong with the code?
You need to close your file output stream I believe.