How we can take input from the file in the Eclipse?
Just like we direct the I/O from the file from the command line.
java MyProgram < input.txt >output.txt
I am unable to direct the input.
but output directing is easy.
Just go->Run->Run->Configurations->Common
Why don't you use File instead of redirection?
Your program will have a fileName as input and then write the result in a file.
If you need necessarily use the default in you can do something like this:
System.setIn(new FileInputStream("testFile.txt"));
a sample of how it works follows:
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
public class TestSystemIn {
public static void main(final String[] args) throws IOException {
// prepare test
FileOutputStream fos = new FileOutputStream("testFile.txt");
fos.write("testToken".getBytes());
// configure env
System.setIn(new FileInputStream("testFile.txt"));
// perform read test
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
System.out.println("read: " + br.readLine());
}
}
The output could be done in the same way using:
System.setOut(new PrintStream("testFile.txt"));
Related
I've written some java code that creates a CSV file at the mount point of a disk I have attached to a Google Compute instance. I run the script in the form of a SQL stored procedure from the instance that the disk is attached to. The issue is that at the mount point, a "lost+found" folder is created where I would expect to find my CSV file. What am I doing wrong? Thank you for your time! The code is similar to as follows:
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.FileOutputStream;
public class file_write {
public static void main(String[] args) throws IOException{
String filePath = "/mnt/point/file.csv";
// Creates file in mount point
File myFile = new File(filePath);
myFile.getParentFile().mkdirs();
myFile.createNewFile();
FileWriter stringWriter = new FileWriter(myFile);
for(int i = 0; i < 100000; i++) {
stringWriter.write(i + ", ");
stringWriter.write("something");
stringWriter.write(System.lineSeparator());
}
stringWriter.close();
}
}
Please keep in mind that I am completely new to Java. I don't know what 'classes' and stuff are.
When trying to compile (javac -g Sphinx.java) this code:
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.PrintWriter;
import api.Configuration;
import api.SpeechResult;
import api.LiveSpeechRecognizer;
public class Sphinx {
public static void main(String[] args) throws Exception {
Configuration configuration = new Configuration();
configuration.setAcousticModelPath("models/en-us/en-us");
configuration.setDictionaryPath("models/en-us/cmudict-en-us.dict");
configuration.setLanguageModelPath("models/en-us/en-us.lm.bin");
PrintWriter pw = new PrintWriter(new PrintWriter("status.txt"));
LiveSpeechRecognizer recognizer = new LiveSpeechRecognizer(configuration);
recognizer.startRecognition(true);
pw.print("running");
SpeechResult result = recognizer.getResult();
recognizer.stopRecognition();
pw.print("stopped");
pw.close();
PrintWriter pw2 = new PrintWriter(new PrintWriter("result.txt"));
pw2.println(result);
pw2.close();
}
}
I get this error:
Sphinx.java:8: error: cannot access Configuration
import api.Configuration;
^
bad source file: .\api\Configuration.java
file does not contain class api.Configuration
Please remove or make sure it appears in the correct subdirectory of the sourcepath.
I don't quite understand what 'file does not contain class api.configuration' means, or how to fix it.
Looking at your error message, it seems like your ./api/Configuration.java file is missing a package declaration.
Can you make sure that in ./api/Configuration.java the first line has
package api;
This tells the compiler that your file is accessible through the api package, not the default package.
I'm trying to write some text to an html file as an output using PrintWriter, and the text isn't saving to the file.
import java.util.Random;
import java.util.*;
import java.io.PrintWriter;
import java.io.File;
import java.io.FileNotFoundException;
public class Creator
{
static ArrayList<Character> grid = new ArrayList<Character>();
public static void main(String[]args) throws FileNotFoundException
{
char[] alphabet={'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'};
for(int row=0;row<625;row++)
{
grid.add(alphabet[RandGen(0,25)]);
//System.out.print(grid.get(out));
}
Creator.Output();
System.out.println("Executed.");
}
public static int RandGen(int min, int max)
{
Random ran = new Random();
int randomNum = ran.nextInt(max) + min;
return randomNum;
}
public static void Output()throws FileNotFoundException
{
//File file=new File("wsm.html");
//File.createNewFile();
PrintWriter writer = new PrintWriter("wordsearchmaker.html");
writer.println("<html>");
writer.println("<table>");
writer.println("tr");
for(int j=0;j<25;j++)
{
//for(int k=0;k<25;k++)
// {
System.out.println("<th>"+grid.get(j));
writer.println("<th>"+grid.get(j));
// }
}
writer.flush();
writer.close();
System.out.println("Outputting...");
}
}
So I've checked that the methods are all running (hence the "outputting..."), and I system.out.printed the content that I'm intending to write to the file, which is outputting exactly what I want it to. It's supposed to output html code into a html file (named wordsearchmaker.html), but nothing is saving to the file. Everywhere I looked online just said to make sure I'm closing the writer, which I did.
Note: I am working in eclipse, which has always been kind of finicky with me, so I may be messing something up there? I don't usually work in eclipse so that's totally possible.
It looks like you've opened the PrintWriter, which enables you to send data to the file. But you haven't actually opened or created a file.
Try first creating a new file and modifying it:
import java.io.File;
File newFile = new File ("LOCATION OF FILE");
Then, set your PrintWriter to use newFile.
I have a program that ask the user for what application it want to open,
this is how the program works:
the user write what application it want to open in a "inputDialog" example the user write "Open application Notepad".
the program looks for the word "application" in the text file so the program is sure that it was a application the user wanted to open.
both the "open application" sentence and the application name get stored in a text file.
then does program remove "Open application" from the text file, and then is only the application name visible.
but always a space comes in front of the application name. Please help me remove the space infront of the application name!!
Here is my code:
package Test_Code;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;
import javax.swing.JOptionPane;
public class New_Loader_3 {
public static void main(String[]args) throws IOException{
String Test = JOptionPane.showInputDialog("Test");
BufferedWriter writer = new BufferedWriter(new FileWriter("/Applications/Userdata/tmp/Application.txt"));
writer.write(Test);
writer.close();
int tokencount;
FileReader fr=new FileReader("/Applications/Userdata/tmp/Application.txt");
BufferedReader br=new BufferedReader(fr);
String s1;
int linecount=0;
String line;
String words[]=new String[500];
while ((s1=br.readLine())!=null)
{
linecount++;
int indexfound=s1.indexOf("application");
if (indexfound>-1)
{
FileInputStream fstream1121221 = new FileInputStream("/Applications/Userdata/tmp/Application.txt");
DataInputStream in1121211 = new DataInputStream(fstream1121221);
BufferedReader br1112211 = new BufferedReader(new InputStreamReader(in1121211));
String Name12122131;
while ((Name12122131 = br1112211.readLine()) != null) {
if (Name12122131.startsWith(" "))
{
System.out.println("Name12122131");
}
}
String mega = Test.replaceAll("Open application","");
System.out.println(mega);
BufferedWriter Update_Catch = new BufferedWriter(new FileWriter("/Applications/Userdata/tmp/Application.txt"));
Update_Catch.write(mega);
Update_Catch.close();
}
}
System.out.println("Done");
}
}
It's because the user types in Open<space>application<space>Notepad. Now when you replace Open<space>Applicaton the space before Notepad is still left. So I just you use this instead:
String mega = Test.replaceAll("Open application ","");
Adding a <space> at the end of Open<space>Application will replace the space too. So now mega will be Notepad.
Otherwise you could use what you're already using and then call mega.trim()
So I am trying to write an .sh file that will be executable, this is how I'm currently writing it:
Writer output = null;
try {
output = new BufferedWriter(new FileWriter(file2));
output.write(shellScriptContent);
output.close();
} catch (IOException ex) {
Logger.getLogger(PunchGUI.class.getName()).log(Level.SEVERE, null, ex);
}
So that writes the file just fine, but it is not executable. Is there a way to change the executable status when I write it?
Edit: To further clarify, I am trying to make it execute by default, so that for instance, if you double clicked the generated file, it would automatically execute.
You can call File.setExecutable() to set the owner's executable bit for the file, which might be sufficient for your case. Or you can just chmod it yourself with a system call with Process.
Alas, full-powered programmatic alteration of file permissions isn't available until Java 7. It'll be part of the New IO feature set, which you can read more about here.
You'd need to chmod it, and you can probably do it by exec'ing a system command like such:
Really all you'd need is to fire off something like this:
Runtime.getRuntime().exec("chmod u+x "+FILENAME);
But if you want to keep track of it more explicitly can capture stdin / stderr then something more like:
Process p = Runtime.getRuntime().exec("chmod u+x "+FILENAME);
BufferedReader stdInput = new BufferedReader(new InputStreamReader(p.getInputStream()));
BufferedReader stdError = new BufferedReader(new InputStreamReader(p.getErrorStream()));
Which I got from here:
http://www.devdaily.com/java/edu/pj/pj010016/pj010016.shtml
Update:
Test program:
package junk;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.io.Writer;
public class Main{
private String scriptContent = '#!/bin/bash \n echo "yeah toast!" > /tmp/toast.txt';
public void doIt(){
try{
Writer output = new BufferedWriter(new FileWriter("/tmp/toast.sh"));
output.write(scriptContent);
output.close();
Runtime.getRuntime().exec("chmod u+x /tmp/toast.sh");
}catch (IOException ex){}
}
public static void main(String[] args){
Main m = new Main();
m.doIt();
}
}
On linux if you open up a file browser and double click on /tmp/toast.sh and choose to run it, it should generate a text file /tmp/toast.txt with the words 'yeah toast'. I assume Mac would do the same since it's BSD under the hood.
In Java 7 you can call Files.setPosixFilePermissions. Here is an example:
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.attribute.PosixFilePermission;
import java.util.Set;
class FilePermissionExample {
public static void main(String[] args) throws IOException {
final Path filepath = Paths.get("path", "to", "file.txt");
final Set<PosixFilePermission> permissions = Files.getPosixFilePermissions(filepath);
permissions.add(PosixFilePermission.OWNER_EXECUTE);
Files.setPosixFilePermissions(filepath, permissions);
}
}
On Mac OS X, besides chmod +x, you have to give a .command extension to your shell script if you want to launch it with a double-click.
This answer I wrote for the question how do I programmatically change file permissions shows a chmod example via a native call using jna, which should work on Mac OS X.