I have two projects-try.java and another.java. I would like to run another,java from try.java
here is my code for another.java
package another;
public class Another {
public static void main(String[] args)
{
System.out.println("Another Java Project");
}
}
Here is mycode for try.java
package pkgtry;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
public class Try
{
private static void printLines(String name, InputStream ins) throws Exception {
String line = null;
BufferedReader in = new BufferedReader(new InputStreamReader(ins));
while ((line = in.readLine()) != null)
{
System.out.println(name + " " + line);
}
}
private static void runProcess(String command) throws Exception
{
Process pro = Runtime.getRuntime().exec(command);
printLines(command + " stdout:", pro.getInputStream());
printLines(command + " stderr:", pro.getErrorStream());
pro.waitFor();
System.out.println(command + " exitValue() " + pro.exitValue());
}
public static void main(String[] args)
{
try
{
runProcess("javac C:\\Users\\owner\\Documents\\NetBeansProjects\\try\\src\\pkgtry\\Another.java");
runProcess("java C:\\Users\\owner\\Documents\\NetBeansProjects\\try\\src\\pkgtry\\Another");
}
catch (Exception e)
{
e.printStackTrace();
}
}
}
After running the Try.java Its not printing anything. Its just printing build successful in netbeans. But a class Another.cass has been created
Can anyone help me?
The java compiler is trying to find Another.java file inside package pkgtry. If you put both the files in one package then you will able to achieve desired result.
public static void main(String[] args)
{
try
{
runProcess("javac Another.java");
runProcess("java Another");
}
catch (Exception e)
{
e.printStackTrace();
}
}
It looks like Another.java isn't in the directory you're running your code from. In particular, you are managing to invoke both javac and java, and it looks like both are receiving the arguments you've specified - but it can't find Another.java.
Additionally, you need to provide the fully-qualified class name to java, which in this case is another.Another as it's in the another package. That also means you need to compile it in such a way that will leave the class file in an appropriate directory structure.
So you want something like:
runProcess("javac -d . path/to/Another.java");
runProcess("java another.Another");
(Where path/to/Another.java is either an absolute filename or one relative to the working directory.)
The -d . will tell javac to build a directory structure rooted in the current working directory for the output files.
EDIT: Now we know where you're running, you could use:
runProcess("javac -d . src/pkgtry/Another.java");
runProcess("java another.Another");
Note that you should keep your source organized in a folder structure to match the package structure, so it should be in a directory called another, not pkgtry
What about doing like this:
try
{
runProcess("cd C:\\Users\\owner\\Documents\\NetBeansProjects\\try\\src\\pkgtry);
runProcess("javac Another.java");
runProcess("java Another");
}
Is there any chance it could work that way?
Related
I created an easy script with notepad++ and run in the cmd with this command:
java -cp . Test
Result:
Error: Main class Test could not be found or loaded
Code:
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
public class Main {
public static void main(String[] args) {
String fileName = "npcData.csv";
String line = "";
String csvSplitBy = ";";
try (BufferedReader br = new BufferedReader(new FileReader(fileName))) {
while ((line = br.readLine()) != null) {
String[] npc = line.split(csvSplitBy);
System.out.println("nonCritSpecialNpc['" + npc[0] + "'] = true;");
}
} catch (IOException e) {
System.out.println("Fehler beim Lesen der Datei: " + e.getMessage());
}
}
}
What am I'm missing?
There are a couple of things you're missing here.
First, for public classes, the name of the class should match the name of the file. I.e., you either need to rename your class to Test, or rename the file to Main.java.
Second, you're missing a crucial step here - compiling. Java is not an interpreted language. You need to convert your .java class to something the JVM can run. This is done using the Java Compiler, or javac for short:
javac Main.java
After doing that, you'll have a .class file that the JVM can execute:
java -cp . Main
I'm using Java to create a program that takes in a CSV file and outputs an Arff file. Whenever the program runs it comes up catching the exception that No source has been specified. When I delete the try catch it comes with the following error and I am not sure why,
Exception in thread "main" java.io.IOException: No source has been specified
at weka.core.converters.CSVLoader.getDataSet(CSVLoader.java:867)
at CSVtoArff.Convert(CSVtoArff.java:10)
at CSVtoArff.main(CSVtoArff.java:23)
Below is the code for the program
import weka.core.Instances;
import weka.core.converters.CSVLoader;
import weka.core.converters.ArffSaver;
import java.io.File;
public class CSVtoArff {
public static void Convert(String input, String output) throws Exception {
try {
CSVLoader load = new CSVLoader();
load.setSource(new File(input));
Instances data = load.getDataSet();
ArffSaver save = new ArffSaver();
save.setInstances(data);
save.setFile(new File(output));
save.writeBatch();
System.out.println("File successfully converted");
}
catch (Exception e) {
System.out.println("Does not meet arff standards: " + e.getMessage());
}
}
public static void main(String[] args) throws Exception{
String input = "C:\\Users\\jason\\Desktop\\example.csv";
String output =" C:\\Users\\jason\\Desktop\\example.arff";
Convert(input, output);
}
}
Please try putting the files in C:\temp folder and change it to below and try.
Sometime windows security my be denying access to protected system folders.
Also there is an extra leading space in output file path. I have removed that.
public static void main(String[] args) throws Exception{
String input = "C:/temp/example.csv";
String output ="C:/temp/example.arff";
Convert(input, output);
}
I'm trying to run a python script whenever a button on my gui (swing) is pressed. However, the script never runs and I'm not sure how to fix this. I know the script works fine independently, it should be py not python because windows, and my file system ntfs.
So far I've been trying to use code that can be summarized as below:
myBtn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
try {
Process p = Runtime.getRuntime().exec("py myScript.py");
} catch (IOException ioe) {
ioe.printStackTrace();
}
}
});
I don't think I can chmod ntfs stuff but I tried setting permissions via right clicking the python file and trying to mess with the security settings. Full control for the script to users does nothing.
The python script has the following permissions, my guess is my code isn't working because it does not have execute permissions.
-rw-r--r--
Use complete python executable path instead of "py". It executes the file with just read permissions.
import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Scanner;
public class Sample {
public static void main(String[] args) throws Exception {
try {
Process p = Runtime.getRuntime().exec("C:/Windows/py myScript.py");
String cmdOutput = null;
BufferedReader stdInput = new BufferedReader(new InputStreamReader(p.getInputStream()));
// read the output from the command
while ((cmdOutput = stdInput.readLine()) != null) {
System.out.println(cmdOutput);
}
} catch (IOException ioe) {
ioe.printStackTrace();
}
}
}
myScript.py
print("This line will be printed.")
Output:
C:\Users\Administrator\Documents\demo>javac Sample.java
C:\Users\Administrator\Documents\demo>java Sample
This line will be printed.
I have a method as follows:
public(String input_filename, String output_filename)
{
//some content
}
how to create an input_filename at run time and read the input_filename .I have to pass input_filename as a parameter
Please be patient as I am new to Java
Here a complete sample:
Save it as Sample.java
compile it with: javac Sample.java
run it with: java Sample "in.txt" "out.txt"
or: java Sample
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;
public class Sample {
public static void main(String[] args) throws IOException {
if(args.length == 2)
{
doFileStuff(args[0],args[1]);
}
else {
doFileStuff("in.txt","out.txt");
}
}
public static void doFileStuff(String input_filename, String output_filename) throws IOException {
if(!Files.exists(Paths.get(input_filename)))
{
System.err.println("file not exist: " + input_filename);
return;
}
if(!Files.exists(Paths.get(output_filename)))
{
System.err.println("file still exist, do not overwrite it: " + output_filename);
return;
}
String content = new String(Files.readAllBytes(Paths.get(input_filename)));
content += "\nHas added something";
Files.write(Paths.get(output_filename), content.getBytes(StandardCharsets.UTF_8));
}
}
I'm unsure what you want to do with this method, but I hope this can help you a bit.
If you want inputs during runtime, use the Scanner class. A guide on how to use it here
Also if you want an output in your class you should use "return", and not have it as a parameter.
Do note that you haven't named your class yet, or specified the output type.
How it could look:
public String className(String input){
return input;
}
What I am trying to achieve is basically a Java file which looks through a specific directory on the users computer, search all the files in the directory for specific word (in this case an email) and then at the end print them out.
The current script of which I have now, looks for all the files in a certain directory, prints out those file names. As well as that I have also figured out how to have that script search through one file for a specific word and then print it out. The only problem is that although it searches through that one file and gets that word/phrase it has to be given the full directory and file to work. I just want it to have a specific directory and then search all the files in it. I have tried doing this using the directory variable of which I have created to find all files, but it does not work when using that as the directory for the files to search through to find the word(s).
Here underneath is the part of my code which is used for the function I want. The actual function is called in my real script so don't worry about that as it is working. I have also just commented in the script what variable I want to work where.
package aProject;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
public class aScanner {
static String usernameMac = System.getProperty("user.name");
final static File foldersMac = new File("/Users/" + usernameMac + "/Library/Mail/V2"); // this is the right directory I want to look through
public static void listFilesForFolder(final File foldersMac) {
for (final File fileEntry : foldersMac.listFiles()) {
if (fileEntry.isDirectory()) {
listFilesForFolder(fileEntry);
try {
BufferedReader bReaderM = new BufferedReader(new FileReader("/Users/username/Library/Mail/V2/AosIMAP-/INBOX.mbox/longnumber-folder/Data/Messages/1.emlx")); //this is where I would like the foldersMac variable to work in, instead of this full directory
String lineMe;
while((lineMe = bReaderM.readLine()) != null)
{
if(lineMe.contains(".com"))
System.out.println(lineMe);
}
bReaderM.close();
}
catch (IOException e) {
}
} else {
System.out.println(fileEntry.getName());
}
}
}
}
I think this is what you're trying to achieve:
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
public class aScanner {
static String usernameMac = System.getProperty("user.name");
final static File foldersMac = new File("/Users/" + usernameMac + "/Library/Mail/V2");
public static void main(String[] args) throws IOException {
listFilesForFolder(foldersMac);
}
public static void listFilesForFolder(final File foldersMac) throws IOException {
for (final File fileEntry : foldersMac.listFiles()) {
if (fileEntry.isDirectory()) {
listFilesForFolder(fileEntry);
} else {
ArrayList<String> lines = new ArrayList<>();
try (BufferedReader bReaderM = new BufferedReader(new FileReader(fileEntry))) {
String lineMe;
while ((lineMe = bReaderM.readLine()) != null) {
if (lineMe.contains(".com")) {
lines.add(lineMe);
}
}
}
if (!lines.isEmpty()) {
System.out.println(fileEntry.getAbsolutePath() + ":");
for (String line : lines) {
System.out.println(" " + line.trim());
}
}
}
}
}
}
I think your problem lies around your recursion logic,
You go down recursively in the directory structure, you walk through you tree, but write out nothing cause of this if statement:
if (fileEntry.isDirectory()) {
listFilesForFolder(fileEntry);
...
}
Close that If statement earlier, then it should work.