Java 教程

Java 控制语句

面向对象编程

Java内置类

Java文件处理

Java错误与异常

Java多线程

Java同步

Java网络编程

Java集合

Java接口

Java数据结构

Java集合算法

高级Java

Java杂项

Java APIs与框架

Java类引用

Java有用资源

Java - 进程API改进



在Java 9中,负责控制和管理操作系统进程的Process API得到了相当大的改进。ProcessHandle类现在提供了进程的原生进程ID、启动时间、累积CPU时间、参数、命令、用户、父进程和子进程。ProcessHandle类还提供方法来检查进程的活动状态和销毁进程。它具有onExit方法,CompletableFuture类可以在进程退出时异步执行操作。

生成新进程示例

在这个例子中,我们为记事本创建了一个新的进程,并使用ProcessBuilder启动它。使用ProcessHandle.Info接口,我们获取了新生成的进程的进程信息。

package com.tutorialspoint;

import java.time.ZoneId;
import java.util.stream.Stream;
import java.util.stream.Collectors;
import java.io.IOException;

public class Tester {
   public static void main(String[] args) throws IOException {
      ProcessBuilder pb = new ProcessBuilder("notepad.exe");
      String np = "Not Present";
      Process p = pb.start();
      ProcessHandle.Info info = p.info();
      System.out.printf("Process ID : %s%n", p.pid());
      System.out.printf("Command name : %s%n", info.command().orElse(np));
      System.out.printf("Command line : %s%n", info.commandLine().orElse(np));

      System.out.printf("Start time: %s%n",
         info.startInstant().map(i -> i.atZone(ZoneId.systemDefault())
         .toLocalDateTime().toString()).orElse(np));

      System.out.printf("Arguments : %s%n",
         info.arguments().map(a -> Stream.of(a).collect(
         Collectors.joining(" "))).orElse(np));

      System.out.printf("User : %s%n", info.user().orElse(np));
   } 
}

输出

您将看到类似的输出。

Process ID : 5580
Command name : C:\Program Files\WindowsApps\Microsoft.WindowsNotepad_11.2401.26.0_x64__8wekyb3d8bbwe\Notepad\Notepad.exe
Command line : Not Present
Start time: 2024-04-02T17:07:14.305
Arguments : Not Present
User : DESKTOP\Tutorialspoint

获取当前进程信息示例

在这个例子中,我们使用ProcessHandle.current()方法获取当前进程。然后使用ProcessHandle.Info接口,我们获取当前进程的进程信息。

package com.tutorialspoint;

import java.time.ZoneId;
import java.util.stream.Stream;
import java.util.stream.Collectors;
import java.io.IOException;

public class Tester {
   public static void main(String[] args) throws IOException {
      String np = "Not Present";
      ProcessHandle currentProcess = ProcessHandle.current();
      ProcessHandle.Info info = currentProcess.info();
      System.out.printf("Process ID : %s%n", currentProcess.pid());
      System.out.printf("Command name : %s%n", info.command().orElse(np));
      System.out.printf("Command line : %s%n", info.commandLine().orElse(np));

      System.out.printf("Start time: %s%n",
         info.startInstant().map(i -> i.atZone(ZoneId.systemDefault())
         .toLocalDateTime().toString()).orElse(np));

      System.out.printf("Arguments : %s%n",
         info.arguments().map(a -> Stream.of(a).collect(
         Collectors.joining(" "))).orElse(np));

      System.out.printf("User : %s%n", info.user().orElse(np));
   } 
}

输出

您将看到类似的输出。

Process ID : 5352
Command name : C:\Program Files\Java\jdk-21\bin\javaw.exe
Command line : Not Present
Start time: 2024-04-02T17:09:17.902
Arguments : Not Present
User : DESKTOP-DTHL8BI\Tutorialspoint

获取子进程示例

在这个例子中,我们使用ProcessHandle.current().children()方法获取当前进程的子进程。然后使用ProcessHandle.Info接口,我们获取子进程的进程信息。

package com.tutorialspoint;

import java.io.IOException;
import java.util.stream.Stream;

public class Tester {
   public static void main(String[] args) throws IOException {
      for (int i = 0; i < 3; i++) {
         ProcessBuilder processBuilder
            = new ProcessBuilder("java.exe", "-version");
         processBuilder.inheritIO().start();
      }
      Stream<ProcessHandle> childProcesses = ProcessHandle.current().children();
      String np = "Not Present";
      childProcesses.filter(ProcessHandle::isAlive).forEach(
         childProcess ->{
            System.out.printf("Process ID : %s%n", childProcess.pid());
            System.out.printf("Command name : %s%n", childProcess.info().command().orElse(np));
            System.out.printf("Command line : %s%n", childProcess.info().commandLine().orElse(np));
         }
      );
   } 
}

输出

您将看到类似的输出。

Process ID : 5420
Command name : C:\Program Files\Java\jdk-21\bin\java.exe
Command line : Not Present
Process ID : 15796
Command name : C:\Program Files\Java\jdk-21\bin\java.exe
Command line : Not Present
Process ID : 14180
Command name : C:\Program Files\Java\jdk-21\bin\java.exe
Command line : Not Present
java version "21.0.2" 2024-01-16 LTS
Java(TM) SE Runtime Environment (build 21.0.2+13-LTS-58)
Java HotSpot(TM) 64-Bit Server VM (build 21.0.2+13-LTS-58, mixed mode, sharing)
java version "21.0.2" 2024-01-16 LTS
Java(TM) SE Runtime Environment (build 21.0.2+13-LTS-58)
Java HotSpot(TM) 64-Bit Server VM (build 21.0.2+13-LTS-58, mixed mode, sharing)
java version "21.0.2" 2024-01-16 LTS
Java(TM) SE Runtime Environment (build 21.0.2+13-LTS-58)
Java HotSpot(TM) 64-Bit Server VM (build 21.0.2+13-LTS-58, mixed mode, sharing)
广告