Java 9 进程 API 概览
在 Java 9 中，用于控制和管理操作系统进程的 Process API 得到了显著改进。ProcessHandle 类现在提供了进程的本地进程 ID、启动时间、累积的 CPU 时间、参数、命令、用户、父进程以及后代进程的信息。此外，ProcessHandle 类还提供检查进程存活状态以及销毁进程的方法。它具有 onExit 方法，允许使用 CompletableFuture 类来在进程退出时异步执行动作。
示例一：创建新进程
在这个示例中，我们创建了一个新的 notepad 进程，并使用 ProcessBuilder 启动了它。通过 ProcessHandle.Info 接口获取新创建进程的信息。
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
您将看到类似如下输出：
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
示例二：获取当前进程信息
在这个示例中，我们使用 ProcessHandle.current() 方法获取当前进程。然后通过 ProcessHandle.Info 接口来获取当前进程的信息。
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
您将看到类似如下输出：
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
示例三：获取子进程
在这个示例中，我们使用 ProcessHandle.current().children() 方法获取当前进程的子进程。然后通过 ProcessHandle.Info 接口来获取子进程的信息。
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
您将看到类似如下输出：
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)