Java，检查当前是否有任何进程 ID 在 Windows 上运行

Question

是否可以在 Windows 中检查来自 Java 的进程是否存在。

我有它可能的PID，我想知道它是否还在运行。

Answer 1

如何使用 Java 检查 pid 是否在 Windows 上运行:

Windows 任务列表命令:

DOS 命令 tasklist 显示一些关于正在运行的进程的输出:

C:\Documents and Settings\eric>tasklist

Image Name                   PID Session Name     Session#    Mem Usage
========================= ====== ================ ======== ============
System Idle Process            0 Console                 0         28 K
System                         4 Console                 0        244 K
smss.exe                     856 Console                 0        436 K
csrss.exe                    908 Console                 0      6,556 K
winlogon.exe                 932 Console                 0      4,092 K
....
cmd.exe                     3012 Console                 0      2,860 K
tasklist.exe                5888 Console                 0      5,008 K

C:\Documents and Settings\eric>

第二列是PID

您可以使用 tasklist 获取特定 PID 的信息:

tasklist /FI "PID eq 1300"

打印:

Image Name                   PID Session Name     Session#    Mem Usage
========================= ====== ================ ======== ============
mysqld.exe                  1300 Console                 0     17,456 K

C:\Documents and Settings\eric>

响应意味着 PID 正在运行。

如果您查询一个不存在的 PID，您会得到:

C:\Documents and Settings\eric>tasklist /FI "PID eq 1301"
INFO: No tasks running with the specified criteria.
C:\Documents and Settings\eric>

Java 函数可以自动执行上述操作

此功能仅适用于具有可用的 tasklist 的 Windows 系统。

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;

public class IsPidRunningTest {

    public static void main(String[] args) {

        //this function prints all running processes
        showAllProcessesRunningOnWindows();

        //this prints whether or not processID 1300 is running
        System.out.println("is PID 1300 running? " + 
            isProcessIdRunningOnWindows(1300));

    }

    /**
     * Queries {@code tasklist} if the process ID {@code pid} is running.
     * @param pid the PID to check
     * @return {@code true} if the PID is running, {@code false} otherwise
     */
    public static boolean isProcessIdRunningOnWindows(int pid){
        try {
            Runtime runtime = Runtime.getRuntime();
            String cmds[] = {"cmd", "/c", "tasklist /FI \"PID eq " + pid + "\""};
            Process proc = runtime.exec(cmds);

            InputStream inputstream = proc.getInputStream();
            InputStreamReader inputstreamreader = new InputStreamReader(inputstream);
            BufferedReader bufferedreader = new BufferedReader(inputstreamreader);
            String line;
            while ((line = bufferedreader.readLine()) != null) {
                //Search the PID matched lines single line for the sequence: " 1300 "
                //if you find it, then the PID is still running.
                if (line.contains(" " + pid + " ")){
                    return true;
                }
            }

            return false;
        } catch (Exception ex) {
            ex.printStackTrace();
            System.out.println("Cannot query the tasklist for some reason.");
            System.exit(0);
        }

        return false;

    }

    /**
     * Prints the output of {@code tasklist} including PIDs.
     */
    public static void showAllProcessesRunningOnWindows(){
        try {
            Runtime runtime = Runtime.getRuntime();
            String cmds[] = {"cmd", "/c", "tasklist"};
            Process proc = runtime.exec(cmds);
            InputStream inputstream = proc.getInputStream();
            InputStreamReader inputstreamreader = new InputStreamReader(inputstream);
            BufferedReader bufferedreader = new BufferedReader(inputstreamreader);
            String line;
            while ((line = bufferedreader.readLine()) != null) {
                System.out.println(line);
            }
        } catch (Exception ex) {
            ex.printStackTrace();
            System.out.println("Cannot query the tasklist for some reason.");
        }
    }
}

上面的 Java 代码打印所有正在运行的进程的列表，然后打印:

is PID 1300 running? true