Java - Get pid of process and kill it

這邊主要探討的是，如何用Java去查詢OS內正在運行的process pid，利用所執行的command進行篩選，之後再將其kill掉，主要會分成Windows and Linux進行示範!
流程如下:
1. 撰寫一支程式(BackgroundProgram.java)，執行後進行等待直到強制kill掉它為止
2. Export it to Runnable JAR file (命名為reader.jar)
3. 撰寫另一支程式(ProcessManager.java)來進行查詢、刪除的操作

#BackgroundProgram.java
  1. import java.io.BufferedReader;
  2. import java.io.File;
  3. import java.io.FileNotFoundException;
  4. import java.io.FileReader;
  5. import java.io.IOException;
  7. public class BackgroundProgram {
  9. 	public static void main(String args[]){
  10. 		// TODO Auto-generated method stub
  11. 		if(args.length != 1) {
  12. 			System.out.println("Please assign a txt file!!");
  13. 			System.exit(-1);
  14. 		}
  15. 		
  16. 		File file = null;
  17. 		if(args.length == 1) {
  18. 			file = new File(args[0]);
  19. 			if(!file.exists()) {
  20. 				System.out.println("File non-exist!!");
  21. 				System.exit(-1);
  22. 			}
  23. 		}
  24. 		
  25. 		try(BufferedReader br = new BufferedReader(new FileReader(file))){
  26. 			String line = null;
  27. 			while((line = br.readLine()) != null) {
  28. 				System.out.println(line);
  29. 			}
  30. 			while(true) {
  31. 				try {
  32. 					Thread.sleep(5000);
  33. 					System.out.println("...");
  34. 				} catch (InterruptedException e) {
  35. 					// TODO Auto-generated catch block
  36. 					e.printStackTrace();
  37. 				}
  38. 			}
  39. 		} catch (FileNotFoundException e) {
  40. 			// TODO Auto-generated catch block
  41. 			e.printStackTrace();
  42. 		} catch (IOException e) {
  43. 			// TODO Auto-generated catch block
  44. 			e.printStackTrace();
  45. 		}
  46. 	}
  47. }

程式執行時assign一檔案進行讀取與顯示，之後進行等待~
將該程式打包成reader.jar(透過eclipse輸出在此略過)，等等執行語法如下:
$ java -jar reader.jar [file path]

#ProcessManager.java
  1. import java.io.BufferedReader;
  2. import java.io.IOException;
  3. import java.io.InputStreamReader;
  4. import java.util.ArrayList;
  5. import java.util.List;
  6. import java.util.Scanner;
  8. import org.apache.commons.lang3.SystemUtils;
  10. public class ProcessManager {
  12. 	public static void main(String args[]){
  13. 		// TODO Auto-generated method stub
  14. 		Scanner input = new Scanner(System.in);
  15. 		boolean flag = true;
  16. 		while(flag) {
  17. 			System.out.println("(1)List executed 'reader.jar' process (2)Clear executed 'reader.jar' process (3)exit");
  18. 			int option = input.nextInt();
  19. 			switch(option) {
  20. 				case 1:{
  21. 					getProcessInfo();
  22. 					break;
  23. 				}
  24. 				case 2:{
  25. 					String killCmd = "";
  26. 					List<ProcInfo> procLists = getProcessInfo();
  27. 		                        for(int i = 0 ; i < procLists.size() ; i++) {
  28. 		            	           ProcInfo info = procLists.get(i);
  29.     		            	           String pid = info.getPid();
  30. 	            		           if(SystemUtils.IS_OS_WINDOWS) {
  31. 	            			      String windir = System.getenv("windir");
  32. 	            			      killCmd = windir + "\\System32\\taskkill.exe /F /PID "+pid;
  33. 	            		           }else
  34. 	            			      killCmd = "kill -9 "+pid;
  35. 	            		           Process pp;
  36. 					   try {
  37. 					      pp = Runtime.getRuntime().exec(killCmd);
  38. 					      int exitValue = pp.waitFor();
  39. 					      System.out.println("Exec cmd: "+killCmd+", Status: "+exitValue);
  40. 					   } catch (IOException | InterruptedException e1) {
  41. 					      // TODO Auto-generated catch block
  42. 					      e1.printStackTrace();
  43. 					   }
  44. 		                        }
  45. 				        break;
  46. 				}
  47. 				case 3:{
  48. 					flag = false;
  49. 					input.close();
  50. 					break;
  51. 				}
  52. 				default:{
  53. 					System.out.println("Option non-exist!!");
  54. 				}
  55. 			}
  56. 		}
  57. 	}
  58. 	
  59. 	private static List<ProcInfo> getProcessInfo(){
  60. 		List<ProcInfo> procLists = new ArrayList<>();
  61. 		try {
  62. 			List<String> cmds = new ArrayList<>();
  63. 			if(SystemUtils.IS_OS_WINDOWS) {
  64. 				String windir = System.getenv("windir");
  65. 				cmds.add(windir + "\\System32\\wbem\\WMIC.exe");
  66. 				cmds.add("process");
  67. 				cmds.add("where");
  68. 				cmds.add("caption='java.exe'");
  69. 				cmds.add("get");
  70. 				cmds.add("processid,commandline");
  71. 			}else if(SystemUtils.IS_OS_LINUX) {
  72. 				cmds.add("/bin/sh");
  73. 				cmds.add("-c");
  74. 				cmds.add("ps -eo pid,args | grep java");
  75. 			}
  76. 			Process p = Runtime.getRuntime().exec(cmds.toArray(new String[0]));
  77. 			BufferedReader input2 = new BufferedReader(new InputStreamReader(p.getInputStream()));
  78. 			
  79. 			String sp = SystemUtils.IS_OS_WINDOWS ? "  " : " ";
  80. 	                String line;
  81. 	                while ((line = input2.readLine()) != null) {
  82. 	        	   line = line.trim();
  83. 	        	   String spLine[] = line.trim().split(sp);
  84. 	        	   for(int i = 0 ; i < spLine.length ; i++) {
  85. 		        	if(spLine[i].indexOf("reader.jar") > -1) {
  86. 		        		String pid = SystemUtils.IS_OS_WINDOWS ? spLine[spLine.length - 1] : spLine[0];
  87. 		        		int index = line.indexOf(pid);
  88. 		        		String cmd = SystemUtils.IS_OS_WINDOWS ? line.substring(0, index) : line.substring(index + 1);
  89. 		        		procLists.add(new ProcInfo(pid, cmd.trim()));
  90. 		        	}
  91. 	        	   }	
  92. 	                }
  93. 	                input2.close();
  94. 		} catch (IOException e) {
  95. 			// TODO Auto-generated catch block
  96. 			e.printStackTrace();
  97. 		}
  98. 		if(procLists.size() > 0) {
  99. 			System.out.println("=============Process Lists=============");
  100. 			System.out.println(procLists);
  101. 		}else {
  102. 			System.out.println("None");
  103. 		}
  104. 		return procLists;
  105. 	}
  106. }
  107. class ProcInfo{
  108. 	private String pid;
  109. 	private String cmd;
  110. 	
  111. 	public ProcInfo(String pid, String cmd) {
  112. 		this.pid = pid;
  113. 		this.cmd = cmd;
  114. 	}
  116. 	public String getPid() {
  117. 		return pid;
  118. 	}
  120. 	public String getCmd() {
  121. 		return cmd;
  122. 	}
  124. 	@Override
  125. 	public String toString() {
  126. 		return "Process Info [pid = " + pid + ", executed cmd => " + cmd + "]";
  127. 	}
  128. }

這支程式重點在getProcessInfo function，區分成Windows and Linux兩種查詢語法
針對主程序為java進行過濾
#Windwos → WMIC.exe process where caption='java.exe' get processid,commandline
回覆結果如下:
CommandLine                     ProcessId
java  -jar reader.jar word.txt  12976
Note: 即使先針對processid但結果還是先印command line

#Linux → /bin/sh -c ps -eo pid,args | grep java
回覆結果如下:
   2190 java -jar reader.jar word.txt
   2282 grep --color=auto java

過濾後會得到pid and commands，再去過濾commands是否有相關keyword，如reader.jar
最後再進行kill
#Windwos → taskkill.exe /F /PID [pid]
#Linux → kill -9 [pid]

DEMO如下:
#Windows - 上: command line執行；中: 查看工作管理員；下: Eclipse執行ProcessManager操作

#Linux - 上: command line執行；中: top；下: command line執行

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