improve get pid logic

core/src/main/java/com/taobao/arthas/core/util/ApplicationUtils.java

@@ -0,0 +1,32 @@
+package com.taobao.arthas.core.util;
+
+import java.lang.management.ManagementFactory;
+
+/**
+ *
+ * @author hengyunabc 2018-09-30
+ *
+ */
+public class ApplicationUtils {
+
+    private static String PID = "-1";
+
+    static {
+        // https://stackoverflow.com/a/7690178
+        String jvmName = ManagementFactory.getRuntimeMXBean().getName();
+        int index = jvmName.indexOf('@');
+
+        if (index > 0) {
+            try {
+                PID = Long.toString(Long.parseLong(jvmName.substring(0, index)));
+            } catch (Throwable e) {
+                // ignore
+            }
+        }
+    }
+
+    public static String getPid() {
+        return PID;
+    }
+
+}

core/src/main/java/com/taobao/arthas/core/util/Constants.java

@@ -1,7 +1,6 @@
 package com.taobao.arthas.core.util;
 
 import java.io.File;
-import java.lang.management.ManagementFactory;
 
 import com.taobao.arthas.core.view.Ansi;
 
@@ -46,7 +45,7 @@ public interface Constants {
     /**
      * 当前进程PID
      */
-    String PID = ManagementFactory.getRuntimeMXBean().getName().split("@")[0];
+    String PID = ApplicationUtils.getPid();
 
     /**
      * 缓存目录