I have a file with some non-ASCII character like
set myval;[2K[DESC[DESC[D
and I have a Java code to read the file
public static void main(String[] args) {
BufferedReader br = null;
try {
String sCurrentLine;
br = new BufferedReader(new FileReader("output.txt"));
while ((sCurrentLine = br.readLine()) != null) {
System.out.println(sCurrentLine);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (br != null) {
br.close();
}
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
In Netbeans those non ASCII are not shown but in Eclipse console those character are displayed as it is.
I want to know how Netbeans were able to remove those character as i need to clean up my files for those non ASCII characters.
Thanks
The best way to do this is to read the file as bytes, and then configure a specific CharsetDecoder to remove the bytes you do not want to capture.
Related
In java, after getting root permissions, how can I open files with it? Can I open them with File class or do I have to use a command?
You will have to use the su command.
I suggest you have a look at how to use su
Sample code to read a file ( I haven't tested it but it should give you an idea ):
public static void runAsRoot(String[] cmds){
try {
Process p = Runtime.getRuntime().exec("su");
BufferedReader reader = new BufferedReader(p.getInputStream());
StringBuilder out = new StringBuilder();
String line;
while ((line = reader.readLine()) != null) {
out.append(line); // add everything to StringBuilder
// here you can have your logic of comparison.
if(line.toString().equals(".")) {
// do something
}
}
} catch(IOException e) {
e.printStackTrace();
} catch(InterruptedException e) {
e.printStackTrace();
}
I am new to Android development, and I try to access to the internal terminal (/bin/bash, ...) of Android phone using a java method.
Do you know if such java method exist?
Thanks
You can use Runtime and Process to achieve your task.
private static String executeCommand(String command) {
Process process = null;
BufferedReader reader = null;
String result = "";
try {
String line;
process = Runtime.getRuntime().exec(command);
reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
while ((line = reader.readLine()) != null)
result += line + "\n";
} catch (final Exception e) {
e.printStackTrace();
} finally {
try {
if (reader != null)
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
if (process != null)
process.destroy();
} catch (Exception e) {
e.printStackTrace();
}
}
return result;
}
Where command is any available terminal commands like PING 8.8.8.8
I'm not entirely sure as to what you mean by "accessing the internal terminal". But if you would like to execute commands take a look at the documentation of the Runtime class.
Here's an example on how to use it.
I don't know if it is possible or not, but my requirement is like - I have to read data from a file called System.evtx in my java program.
While I am doing this like simple file reading I am getting some ASCII character or I can say un-readable format.
Is there any way to solve this issues.
Thanks in advance.
This is a difficult question to answer without an example of the file content, but after some googling it seems to be a windows event log file? So im unsure about the exact format but apparently they can be converted to .csv files using powershell:
Get-WinEvent -Path c:\path\to\eventlog.evtx |Export-Csv eventlog.csv
Once its in a csv format you could simple parse them in the traditional way of csv or just split by comma's etc.
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
public class CSVReader {
public static void main(String[] args) {
String csvFile = "eventlog.csv";
BufferedReader br = null;
String line = "";
String cvsSplitBy = ",";
try {
br = new BufferedReader(new FileReader(csvFile));
while ((line = br.readLine()) != null) {
// use comma as separator
String[] line = line.split(cvsSplitBy);
for(int i=0;i<line.length;i++){
System.out.println(line[i]);
}
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (br != null) {
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
Goal: Print the data from a .dat file to the console using Eclipse.
(Long-Term Goal): Executable that I can pass a .dat file to and it creates a new txt file with the data formatted.
The .dat: I know the .dat file contains control points that I will need to create a graph with using ECMAScript.
Eclipse Setup:
Created Java Project
New > Class .. called the Class FileRead
Now I have FileRead.java which is:
1/ package frp;
2/
3/ import java.io.BufferedReader;
4/ import java.io.File;
5/ import java.io.FileReader;
6/
7/ public class FileRead {
8/
9/ public static void main(String[] args) {
10/ FileReader file = new FileReader(new File("dichromatic.dat"));
11/ BufferedReader br = new BufferedReader(file);
12/ String temp = br.readLine();
13/ while (temp != null) {
14/ temp = br.readLine();
15/ System.out.println(temp);
16/ }
17/ file.close();
18/ }
19/
20/ }
Please note this approach was borrowed from here: https://stackoverflow.com/a/18979213/3306651
1st Challenge: FileNotFoundException on LINE 10
Screenshot of Project Explorer:
QUESTION: How to correctly reference the .dat file?
2nd Challenge: Unhandled exception type IOException LINES 12, 14, 17
QUESTION: How to prevent these exceptions?
Thank you for your time and effort to help me, I am recreating Java applets using only JavaScript. So, I'm looking to create java tools that extract data I need to increase productivity. If you are interested in phone/web app projects involving JavaScript, feel free to contact me 8503962891
1. Without changing your code, you must place the file in the project's root folder.
Otherwise, reference it as src/frp/dichromatic.dat
2. Doing something like this:
public static void main(String[] args) {
FileReader file = null;
try {
file = new FileReader(new File("dichromatic.dat"));
} catch (FileNotFoundException e1) {
System.err.println("File dichromatic.dat not found!");
e1.printStackTrace();
}
BufferedReader br = new BufferedReader(file);
String line;
try {
while ((line = br.readLine()) != null) {
System.out.println(line);
}
} catch (IOException e) {
System.err.println("Error when reading");
e.printStackTrace();
} finally {
if (br != null) {
try {
br.close();
} catch (IOException e) {
System.err.println("Unexpected error");
e.printStackTrace();
}
}
}
}
3. Creation of a new txt file "formatted". In this example, the formatting will be settings the characters to uppercase.
public static void main(String[] args) {
FileReader file = null;
BufferedWriter bw = null;
File outputFile = new File("output.formatted");
try {
file = new FileReader(new File("dichromatic.dat"));
} catch (FileNotFoundException e1) {
System.err.println("File dichromatic.dat not found!");
e1.printStackTrace();
}
try {
bw = new BufferedWriter(new FileWriter(outputFile));
} catch (IOException e1) {
System.err.println("File is not writtable or is not a file");
e1.printStackTrace();
}
BufferedReader br = new BufferedReader(file);
String line;
String lineformatted;
try {
while ((line = br.readLine()) != null) {
lineformatted = format(line);
bw.write(lineformatted);
// if you need it
bw.newLine();
}
} catch (IOException e) {
System.err.println("Error when processing the file!");
e.printStackTrace();
} finally {
if (br != null) {
try {
br.close();
} catch (IOException e) {
System.err.println("Unexpected error");
e.printStackTrace();
}
}
if (bw != null) {
try {
bw.close();
} catch (IOException e) {
System.err.println("Unexpected error");
e.printStackTrace();
}
}
}
}
public static String format(String line) {
// replace this with your needs
return line.toUpperCase();
}
I would strongly recommend spending some time reading through the Java Trails Tutorials. To answer your specific question, look at Lesson: Exceptions.
To oversimplify, just wrap the file-handling code in a try...catch block. By example:
package frp;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
public class FileRead {
public static void main(String[] args) {
try {
FileReader file = new FileReader(new File("dichromatic.dat"));
BufferedReader br = new BufferedReader(file);
String temp = br.readLine();
while (temp != null) {
temp = br.readLine();
System.out.println(temp);
}
file.close();
} catch (FileNotFoundException fnfe) {
System.err.println("File not found: " + fnfe.getMessage() );
} catch (IOException ioe) {
System.err.println("General IO Error encountered while processing file: " + ioe.getMessage() );
}
}
}
Note that ideally, your try...catch should wrap the smallest possible unit of code. So, wrap the FileReader separately, and "fail-fast" if the file isn't found, and wrap the readLine loop in its own try...catch. For more examples and a better explanation of how to deal with exceptions, please reference the link I provided at the top of this answer.
Edit: issue of file path
Not finding the file has to do with the location of the file relative to the root of the project. In your original post, you reference the file as "dichromatic.dat" but relative to the project root, it is in "src/frp/dichromatic.dat". As rpax recommends, either change the string that points to the file to properly reference the location of the file relative to the project root, or move the file to project root and leave the string as-is.
I got problem in reading the file at the Gui text area hopefully you help me out guys to fix the statement of reading file thank you very much
public static javax.swing.JTextArea jTextArea1;
{
BufferedReader br = null;
try {
String sCurrentLine;
br = new BufferedReader(new FileReader("C:\\testing1.txt"));
while ((sCurrentLine = br.readLine()) != null) {
jTextArea1.read(br, "C:\\testing1.txt"); \\the problem is here
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (br != null)br.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
You can use
JtextArea1.setText(readtext);
but when you use
jTextArea1.append(readtext);
that will append data at the end of already read text in jTextArea
Try one of the following:
jTextArea1.read(br, null);
or
jTextArea1.append(sCurrentLine);
Have a look at this link: http://www.leepoint.net/notes-java/GUI/components/40textarea/20textarea.html