稍微提高了一点用户体验：

vjtop/src/main/java/com/vip/vjtools/vjtop/util/OptionAdvanceParser.java

@@ -22,6 +22,10 @@ public static String parsePid(OptionParser parser, OptionSet optionSet) {
 			pid = Integer.valueOf((String) optionSet.nonOptionArguments().get(0));
 		}
 
+		if (pid == null){
+			pid = SelectPid.getPidFromJpsList();
+		}
+
 		if (pid == null) {
 			System.out.println("PID can't be empty !!!");
 			VJTop.printHelper(parser);

vjtop/src/main/java/com/vip/vjtools/vjtop/util/SelectPid.java

@@ -0,0 +1,62 @@
+package com.vip.vjtools.vjtop.util;
+
+import java.io.BufferedReader;
+import java.io.Console;
+import java.io.InputStreamReader;
+
+/**
+ * Created by traburiss on 2019/12/11.
+ * describe:
+ */
+public class SelectPid {
+
+	public static Integer getPidFromJpsList(){
+
+		Integer pid = null;
+		Process process = null;
+		BufferedReader reader = null;
+		try {
+
+			Console console = System.console();
+			process = Runtime.getRuntime().exec("jps -l");
+			reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
+			String defPidStr = "";
+			String line;
+			System.out.println("please input a pid from list:");
+			System.out.println("PID\tNAME");
+			while ((line = reader.readLine()) != null) {
+				//不显示jps和自己
+				if (!line.contains("sun.tools.jps.Jps") && !line.contains("com.vip.vjtools.vjtop.VJTop")){
+					String[] pm = line.split(" ",2);
+					if (defPidStr.isEmpty()){
+						defPidStr = pm[0];
+					}
+					System.out.println(pm[0] + "\t" + pm[1]);
+				}
+			}
+			String pidString = console.readLine("\nplease input pid(default is " + defPidStr + "):");
+			if (pidString == null || pidString.isEmpty()){
+				pidString = defPidStr;
+			}
+			pid = Integer.valueOf(pidString);
+		}catch (Exception ignored){
+		}finally {
+
+			try {
+				if (reader != null) {
+					reader.close();
+				}
+			} catch (Exception e) {
+				e.printStackTrace();
+			}
+			try {
+				if (process != null) {
+					process.destroy();
+				}
+			} catch (Exception e) {
+				e.printStackTrace();
+			}
+		}
+		return pid;
+	}
+}