In my idea IDE, I can see the compile error with red font in the console.But when I deploy the jar in the linux server.I can not see the compile log.How to print the compile error log?
public static void main(String[] args) throws Exception {
String compliePath="D:\\testFole";
String filename="D:\\test.java";
String[] arg = new String[] { "-d", compliePath, filename };
System.out.println(com.sun.tools.javac.Main.compile(arg));
}
Well if I got your question right, here is an approach to the outcome.
I think this will be platform-independent.
import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStreamReader;
public class Main {
private static Process process;
public static void main(String[] args) {
runCommand();
getErrorMessage();
}
/**
* This method executes/runs the commands
*/
private static void runCommand()
{
File file = new File("D:\\\\test.java");
String changeDirectory = "cmd start cmd.exe /c cd D:\\";
String compile = " && javac D:\\test.java";
String run = " && java "+file.getName().replace(".java","");
String command = changeDirectory + compile + run;
try {
process = Runtime.getRuntime().exec(command);
}catch (IOException e){}
}
/**
* This method will get the errorStream from process
* and output it on the console.
*/
private static void getErrorMessage()
{
try (BufferedReader errorReader = new BufferedReader(new InputStreamReader(process.getErrorStream())))
{
String line;
if(errorReader.readLine() != null)
while ((line = errorReader.readLine()) != null)
System.out.println(line); //display error message
}catch (IOException e){}
}
}
For example, I've test.pptx open in Microsoft PowerPoint 2013 on Windows 10. I want to close it without closing Microsoft PowerPoint itself. How can I do that using Java 1.8?
Because it's external program, you need to kill your PC running power point task.
You can achieve it by using below Java code:
import java.io.BufferedReader;
import java.io.InputStreamReader;
public class ClosePowerPoint {
private static final String TASKLIST = "tasklist";
private static final String KILL = "taskkill /IM ";
public static void main(String args[]) throws Exception {
System.out.print(isProcessRunging("POWERPNT.EXE"));
if (isProcessRunging(processName)) {
killProcess(processName);
}
}
public static boolean isProcessRunging(String serviceName) throws Exception {
Process p = Runtime.getRuntime().exec(TASKLIST);
BufferedReader reader = new BufferedReader(new InputStreamReader(p.getInputStream()));
String line;
while ((line = reader.readLine()) != null) {
System.out.println(line);
if (line.contains(serviceName)) {
return true;
}
}
return false;
}
public static void killProcess(String serviceName) throws Exception {
Runtime.getRuntime().exec(KILL + serviceName);
}
}
TestClass.java
package test;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class TestClass {
public static void main(String[] args) throws IOException {
System.out.println("inside");
ProcessBuilder pb = new ProcessBuilder("java", "-cp", "", "test.OtherClass");
Process p = pb.start();
BufferedReader reader = new BufferedReader(new InputStreamReader(p.getErrorStream()));
StringBuilder builder = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
builder.append(line);
builder.append(System.getProperty("line.separator"));
}
String result = builder.toString();
System.out.println(result);
}
}
OtherClass.java
package test;
public class OtherClass {
public static void main(String ar[]) {
System.out.println("Hello Amit!");
}
}
I am trying to run OtherClass from TestClass, but I am not able to do it. Running TestClass just prints "inside". I am not getting any exception and I am clueless right now.
I am implementing ProcessBuilder for the first time.
NOTE: I was able to run simple program using ProcessBuilder.
Also Can you tell what is meaning of -cp; I googled a lot but could not find its meaning.
EDIT:
I have updated code and now I am getting
inside
Error: Could not find or load main class test.OtherClass
Thanks!
Its likely to be the classpath.
Assuming you have a directory called test, Have you tried something like:
ProcessBuilder pb = new ProcessBuilder("java", "-cp", ".", "test.OtherClass");
How to redirect or get the system output to String?
ProcessBuilder pb = new ProcessBuilder().inheritIO();
...
for (...){
pb.command(...);
pb.start();
//here >>> assign output string to variable
}
Here is an opinion on how to capture the standard output of a system command process into a string container.
Adapted from the web:
try {
ProcessBuilder pb = new ProcessBuilder("echo", "dummy io");
final Process p=pb.start();
BufferedReader br=new BufferedReader(new InputStreamReader(p.getInputStream()));
String line;
StringBuilder sb = new StringBuilder();
while((line=br.readLine())!=null) sb.append(line);
}
System.out.println(sb.toString());
In congruence with my original comment on what would be a good example of Basic I/O. I hacked out some code, with a few more features than basic.
Extras
An environment shell for variables and
A working directory
These features add "profile-style" execution to your System commands.
Foundational Work
Java Threading and Joining by Oracle.
Code
import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.Map;
/**
* Created by triston on 11/2/17.
*/
public class Commander {
private Commander(){} // no construction
public static class StreamHandler implements Runnable {
Object source;
Object destination;
StreamHandler(Object source, Object oDestination) {
this.source = source; this.destination = oDestination;
}
public void run() {
if (source instanceof InputStream) {
BufferedReader br = new BufferedReader(new InputStreamReader((InputStream) source));
String line;
try {
while ((line = br.readLine()) != null) ((StringBuilder) destination).append(line + '\n');
} catch (IOException oE) {
}
} else {
PrintWriter pw = new PrintWriter((OutputStream)destination);
pw.print((String)source);
pw.flush(); pw.close();
}
}
public static Thread read(InputStream source, StringBuilder dest) {
Thread thread = new Thread(new StreamHandler(source, dest));
(thread).start();
return thread;
}
public static Thread write(String source, OutputStream dest) {
Thread thread = new Thread(new StreamHandler(source, dest));
(thread).start();
return thread;
}
}
static Map<String, String> environment = loadEnvironment();
static String workingDirectory = ".";
static Map<String, String> loadEnvironment() {
ProcessBuilder x = new ProcessBuilder();
return x.environment();
}
static public void resetEnvironment() {
environment = loadEnvironment();
workingDirectory = ".";
}
static public void loadEnvirons(HashMap input) {
environment.putAll(input);
}
static public String getEnviron(String name) {
return environment.get(name);
}
static public void setEnviron(String name, String value) {
environment.put(name, value);
}
static public boolean clearEnviron(String name) {
return environment.remove(name) != null;
}
static public boolean setWorkingDirectory(String path) {
File test = new File(path);
if (!test.isDirectory()) return false;
workingDirectory = path;
return true;
}
static public String getWorkingDirectory() {
return workingDirectory;
}
static public class Command {
ProcessBuilder processBuilder = new ProcessBuilder();
Process process;
public Command(String... parameters) {
processBuilder.environment().putAll(environment);
processBuilder.directory(new File(workingDirectory));
processBuilder.command(parameters);
}
public int start(String input, StringBuilder output, StringBuilder error) throws IOException {
// start the process
process = processBuilder.start();
// start the error reader
Thread errorBranch = StreamHandler.read(process.getErrorStream(), error);
// start the output reader
Thread outputBranch = StreamHandler.read(process.getInputStream(), output);
// start the input
Thread inputBranch = StreamHandler.write(input, process.getOutputStream());
int rValue = 254;
try {
inputBranch.join(); rValue--;
outputBranch.join(); rValue--;
errorBranch.join(); rValue--;
return process.waitFor();
} catch (InterruptedException oE) {
oE.printStackTrace();
return rValue;
}
}
}
Testing
#Test public void foo() {
Command cmd = new Command("sh", "--");
StringBuilder output = new StringBuilder();
StringBuilder error = new StringBuilder();
int pValue = 127;
try {
pValue = cmd.start("echo well done > /dev/stderr\n\necho oh, wow; false", output, error);
} catch (IOException oE) {
}
System.out.println("output: "+output.toString());
System.out.println("error: "+error.toString());
System.out.println("\nExit code: "+pValue);
System.exit(pValue);
}
Bring your own package and JUnit annotations. This sample code demonstrates return value, command input, command standard output, and command error output.
My original design, called for the main thread to perform the standard output processing.
Have a great day.
Does any one know how do I get the current open windows or process of a local machine using Java?
What I'm trying to do is: list the current open task, windows or process open, like in Windows Taskmanager, but using a multi-platform approach - using only Java if it's possible.
This is another approach to parse the the process list from the command "ps -e":
try {
String line;
Process p = Runtime.getRuntime().exec("ps -e");
BufferedReader input =
new BufferedReader(new InputStreamReader(p.getInputStream()));
while ((line = input.readLine()) != null) {
System.out.println(line); //<-- Parse data here.
}
input.close();
} catch (Exception err) {
err.printStackTrace();
}
If you are using Windows, then you should change the line: "Process p = Runtime.getRun..." etc... (3rd line), for one that looks like this:
Process p = Runtime.getRuntime().exec
(System.getenv("windir") +"\\system32\\"+"tasklist.exe");
Hope the info helps!
Finally, with Java 9+ it is possible with ProcessHandle:
public static void main(String[] args) {
ProcessHandle.allProcesses()
.forEach(process -> System.out.println(processDetails(process)));
}
private static String processDetails(ProcessHandle process) {
return String.format("%8d %8s %10s %26s %-40s",
process.pid(),
text(process.parent().map(ProcessHandle::pid)),
text(process.info().user()),
text(process.info().startInstant()),
text(process.info().commandLine()));
}
private static String text(Optional<?> optional) {
return optional.map(Object::toString).orElse("-");
}
Output:
1 - root 2017-11-19T18:01:13.100Z /sbin/init
...
639 1325 www-data 2018-12-04T06:35:58.680Z /usr/sbin/apache2 -k start
...
23082 11054 huguesm 2018-12-04T10:24:22.100Z /.../java ProcessListDemo
On Windows there is an alternative using JNA:
import com.sun.jna.Native;
import com.sun.jna.platform.win32.*;
import com.sun.jna.win32.W32APIOptions;
public class ProcessList {
public static void main(String[] args) {
WinNT winNT = (WinNT) Native.loadLibrary(WinNT.class, W32APIOptions.UNICODE_OPTIONS);
WinNT.HANDLE snapshot = winNT.CreateToolhelp32Snapshot(Tlhelp32.TH32CS_SNAPPROCESS, new WinDef.DWORD(0));
Tlhelp32.PROCESSENTRY32.ByReference processEntry = new Tlhelp32.PROCESSENTRY32.ByReference();
while (winNT.Process32Next(snapshot, processEntry)) {
System.out.println(processEntry.th32ProcessID + "\t" + Native.toString(processEntry.szExeFile));
}
winNT.CloseHandle(snapshot);
}
}
The only way I can think of doing it is by invoking a command line application that does the job for you and then screenscraping the output (like Linux's ps and Window's tasklist).
Unfortunately, that'll mean you'll have to write some parsing routines to read the data from both.
Process proc = Runtime.getRuntime().exec ("tasklist.exe");
InputStream procOutput = proc.getInputStream ();
if (0 == proc.waitFor ()) {
// TODO scan the procOutput for your data
}
YAJSW (Yet Another Java Service Wrapper) looks like it has JNA-based implementations of its org.rzo.yajsw.os.TaskList interface for win32, linux, bsd and solaris and is under an LGPL license. I haven't tried calling this code directly, but YAJSW works really well when I've used it in the past, so you shouldn't have too many worries.
You can easily retrieve the list of running processes using jProcesses
List<ProcessInfo> processesList = JProcesses.getProcessList();
for (final ProcessInfo processInfo : processesList) {
System.out.println("Process PID: " + processInfo.getPid());
System.out.println("Process Name: " + processInfo.getName());
System.out.println("Process Used Time: " + processInfo.getTime());
System.out.println("Full command: " + processInfo.getCommand());
System.out.println("------------------");
}
There is no platform-neutral way of doing this. In the 1.6 release of Java, a "Desktop" class was added the allows portable ways of browsing, editing, mailing, opening, and printing URI's. It is possible this class may someday be extended to support processes, but I doubt it.
If you are only curious in Java processes, you can use the java.lang.management api for getting thread/memory information on the JVM.
For windows I use following:
Process process = new ProcessBuilder("tasklist.exe", "/fo", "csv", "/nh").start();
new Thread(() -> {
Scanner sc = new Scanner(process.getInputStream());
if (sc.hasNextLine()) sc.nextLine();
while (sc.hasNextLine()) {
String line = sc.nextLine();
String[] parts = line.split(",");
String unq = parts[0].substring(1).replaceFirst(".$", "");
String pid = parts[1].substring(1).replaceFirst(".$", "");
System.out.println(unq + " " + pid);
}
}).start();
process.waitFor();
System.out.println("Done");
This might be useful for apps with a bundled JRE: I scan for the folder name that i'm running the application from: so if you're application is executing from:
C:\Dev\build\SomeJavaApp\jre-9.0.1\bin\javaw.exe
then you can find if it's already running in J9, by:
public static void main(String[] args) {
AtomicBoolean isRunning = new AtomicBoolean(false);
ProcessHandle.allProcesses()
.filter(ph -> ph.info().command().isPresent() && ph.info().command().get().contains("SomeJavaApp"))
.forEach((process) -> {
isRunning.set(true);
});
if (isRunning.get()) System.out.println("SomeJavaApp is running already");
}
Using code to parse ps aux for linux and tasklist for windows are your best options, until something more general comes along.
For windows, you can reference: http://www.rgagnon.com/javadetails/java-0593.html
Linux can pipe the results of ps aux through grep too, which would make processing/searching quick and easy. I'm sure you can find something similar for windows too.
The below program will be compatible with Java 9+ version only...
To get the CurrentProcess information,
public class CurrentProcess {
public static void main(String[] args) {
ProcessHandle handle = ProcessHandle.current();
System.out.println("Current Running Process Id: "+handle.pid());
ProcessHandle.Info info = handle.info();
System.out.println("ProcessHandle.Info : "+info);
}
}
For all running processes,
import java.util.List;
import java.util.stream.Collectors;
public class AllProcesses {
public static void main(String[] args) {
ProcessHandle.allProcesses().forEach(processHandle -> {
System.out.println(processHandle.pid()+" "+processHandle.info());
});
}
}
String line;
Process process = Runtime.getRuntime().exec("ps -e");
process.getOutputStream().close();
BufferedReader input =
new BufferedReader(new InputStreamReader(process.getInputStream()));
while ((line = input.readLine()) != null) {
System.out.println(line); //<-- Parse data here.
}
input.close();
We have to use process.getOutputStream.close() otherwise it will get locked in while loop.
package com.vipul;
import java.applet.Applet;
import java.awt.Checkbox;
import java.awt.Choice;
import java.awt.Font;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
public class BatchExecuteService extends Applet {
public Choice choice;
public void init()
{
setFont(new Font("Helvetica", Font.BOLD, 36));
choice = new Choice();
}
public static void main(String[] args) {
BatchExecuteService batchExecuteService = new BatchExecuteService();
batchExecuteService.run();
}
List<String> processList = new ArrayList<String>();
public void run() {
try {
Runtime runtime = Runtime.getRuntime();
Process process = runtime.exec("D:\\server.bat");
process.getOutputStream().close();
InputStream inputStream = process.getInputStream();
InputStreamReader inputstreamreader = new InputStreamReader(
inputStream);
BufferedReader bufferedrReader = new BufferedReader(
inputstreamreader);
BufferedReader bufferedrReader1 = new BufferedReader(
inputstreamreader);
String strLine = "";
String x[]=new String[100];
int i=0;
int t=0;
while ((strLine = bufferedrReader.readLine()) != null)
{
// System.out.println(strLine);
String[] a=strLine.split(",");
x[i++]=a[0];
}
// System.out.println("Length : "+i);
for(int j=2;j<i;j++)
{
System.out.println(x[j]);
}
}
catch (IOException ioException)
{
ioException.printStackTrace();
}
}
}
You can create batch file like
TASKLIST /v /FI "STATUS eq running" /FO "CSV" /FI "Username eq LHPL002\soft" /FI "MEMUSAGE gt 10000" /FI "Windowtitle ne N/A" /NH
This is my code for a function that gets the tasks and gets their names, also adding them into a list to be accessed from a list. It creates temp files with the data, reads the files and gets the task name with the .exe suffix, and arranges the files to be deleted when the program has exited with System.exit(0), it also hides the processes being used to get the tasks and also java.exe so that the user can't accidentally kill the process that runs the program all together.
private static final DefaultListModel tasks = new DefaultListModel();
public static void getTasks()
{
new Thread()
{
#Override
public void run()
{
try
{
File batchFile = File.createTempFile("batchFile", ".bat");
File logFile = File.createTempFile("log", ".txt");
String logFilePath = logFile.getAbsolutePath();
try (PrintWriter fileCreator = new PrintWriter(batchFile))
{
String[] linesToPrint = {"#echo off", "tasklist.exe >>" + logFilePath, "exit"};
for(String string:linesToPrint)
{
fileCreator.println(string);
}
fileCreator.close();
}
int task = Runtime.getRuntime().exec(batchFile.getAbsolutePath()).waitFor();
if(task == 0)
{
FileReader fileOpener = new FileReader(logFile);
try (BufferedReader reader = new BufferedReader(fileOpener))
{
String line;
while(true)
{
line = reader.readLine();
if(line != null)
{
if(line.endsWith("K"))
{
if(line.contains(".exe"))
{
int index = line.lastIndexOf(".exe", line.length());
String taskName = line.substring(0, index + 4);
if(! taskName.equals("tasklist.exe") && ! taskName.equals("cmd.exe") && ! taskName.equals("java.exe"))
{
tasks.addElement(taskName);
}
}
}
}
else
{
reader.close();
break;
}
}
}
}
batchFile.deleteOnExit();
logFile.deleteOnExit();
}
catch (FileNotFoundException ex)
{
Logger.getLogger(Functions.class.getName()).log(Level.SEVERE, null, ex);
}
catch (IOException | InterruptedException ex)
{
Logger.getLogger(Functions.class.getName()).log(Level.SEVERE, null, ex);
}
catch (NullPointerException ex)
{
// This stops errors from being thrown on an empty line
}
}
}.start();
}
public static void killTask(String taskName)
{
new Thread()
{
#Override
public void run()
{
try
{
Runtime.getRuntime().exec("taskkill.exe /IM " + taskName);
}
catch (IOException ex)
{
Logger.getLogger(Functions.class.getName()).log(Level.SEVERE, null, ex);
}
}
}.start();
}