使用PHP exec命令打破无限循环java程序

Question

我有 JDK，我正在尝试执行包含无限循环的 Main.java 程序，如果它进入无限循环，我想打破 java Main.java output.txt 命令，如果不是无限循环比不会破坏程序..任何解决方案？遇到麻烦

<?php

exec('cmd /k c:/wamp/www/javac Main.java 2>&1', $outputAndErrors, $return_value);
for($i=0 ; $i<sizeof($outputAndErrors) ; $i++)
{
    $output1=htmlspecialchars($outputAndErrors[$i],ENT_QUOTES);
    echo "$output1";    
    $flag=1;
}
if(!$flag)
{
    exec('cmd /k c:/wamp/www/java Main.java < input.txt > output.txt', $outputAndErrors, $return_value);
    //want to give timeout but if exec goes to infinite loop than below statement will not executed
}

?>

Answer 1

尝试将其包装在这样的类中（基本上将其包装在 nohup COMMAND > /dev/null 2>&1 & echo $! 中以获取 pid 并在后台以这种方式使用它）

<?php
    // You may use status(), start(), and stop(). notice that start() method gets called automatically one time.
    $process = new Process('ls -al');

    // or if you got the pid, however here only the status() metod will work.
    $process = new Process();
    $process.setPid(my_pid);
?>

<?php
    // Then you can start/stop/ check status of the job.
    $process.stop();
    $process.start();
    if ($process.status()){
        echo "The process is currently running";
    }else{
        echo "The process is not running.";
    }
?>

<?php
/* An easy way to keep in track of external processes.
* Ever wanted to execute a process in php, but you still wanted to have somewhat controll of the process ? Well.. This is a way of doing it.
* @compability: Linux only. (Windows does not work).
* @author: Peec
*/
class Process{
    private $pid;
    private $command;

    public function __construct($cl=false){
        if ($cl != false){
            $this->command = $cl;
            $this->runCom();
        }
    }
    private function runCom(){
        $command = 'nohup '.$this->command.' > /dev/null 2>&1 & echo $!';
        exec($command ,$op);
        $this->pid = (int)$op[0];
    }

    public function setPid($pid){
        $this->pid = $pid;
    }

    public function getPid(){
        return $this->pid;
    }

    public function status(){
        $command = 'ps -p '.$this->pid;
        exec($command,$op);
        if (!isset($op[1]))return false;
        else return true;
    }

    public function start(){
        if ($this->command != '')$this->runCom();
        else return true;
    }

    public function stop(){
        $command = 'kill '.$this->pid;
        exec($command);
        if ($this->status() == false)return true;
        else return false;
    }
}
?>

Answer 2

这只是一个建议。您的问题会有更好的答案。

在 java 无限循环中检查来自其他文本文件的一些值。就像

while true {

v = readFile('your_txt_file.txt')
if v == "true" {
    break;
}
//do your stuff   }

如果您可以将 your_txt_file.txt 的值设置为 false，除了 true 之外的任何值，那么 java 循环将被中断。

Answer 3

你需要在java中打开一个端口来监听，然后从php连接并发送一些东西到那个端口。

查看@TomaszNurkiewicz 回答here 他所说的地方

"""

您可能想要的是创建一个 ServerSocket 并监听它：

ServerSocket serverSocket = new ServerSocket(4000);
Socket socket = serverSocket.accept();

第二行将阻塞，直到其他一些软件在端口 4000 上连接到您的计算机。然后您可以从返回的套接字中读取。看看这个教程，这其实是一个很宽泛的话题（线程、协议...）

"""

要使用 php 打开套接字，您可以使用 @sanmi 提供的代码（或接近它的代码）here 来自 the manual

"""

<?php
error_reporting(E_ALL);

/* Get the port for the WWW service. */
$service_port = getservbyname('www', 'tcp');

/* Get the IP address for the target host. */
$address = gethostbyname('www.example.com');

/* Create a TCP/IP socket. */
$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
if ($socket === false) {
    echo "socket_create() failed: reason: " . 
         socket_strerror(socket_last_error()) . "\n";
}

echo "Attempting to connect to '$address' on port '$service_port'...";
$result = socket_connect($socket, $address, $service_port);
if ($result === false) {
    echo "socket_connect() failed.\nReason: ($result) " . 
          socket_strerror(socket_last_error($socket)) . "\n";
}

$in = "HEAD / HTTP/1.1\r\n";
$in .= "Host: www.example.com\r\n";
$in .= "Connection: Close\r\n\r\n";
$out = '';

echo "Sending HTTP HEAD request...";
socket_write($socket, $in, strlen($in));
echo "OK.\n";

echo "Reading response:\n\n";
while ($out = socket_read($socket, 2048)) {
    echo $out;
}

socket_close($socket);
?>

"""