refactor Vmtool, support singleton, support VMtoolMXBean. #1781

arthas-vmtool/src/main/java/arthas/VMtoolMXBean.java

@@ -0,0 +1,48 @@
+package arthas;
+
+import java.util.ArrayList;
+
+/**
+ * VMtool interface for JMX server. How to register VMtool MBean:
+ *
+ * <pre>
+ * {@code
+ *     ManagementFactory.getPlatformMBeanServer().registerMBean(
+ *             VMtool.getInstance(),
+ *             new ObjectName("arthas:type=VMtool")
+ *     );
+ * }
+ * </pre>
+ * @author hengyunabc 2021-04-26
+ */
+public interface VMtoolMXBean {
+    /**
+     * 检测jni-lib是否正常，如果正常，应该输出OK
+     */
+    public String check();
+
+    /**
+     * 获取某个class在jvm中当前所有存活实例
+     */
+    public <T> ArrayList<T> getInstances(Class<T> klass);
+
+    /**
+     * 统计某个class在jvm中当前所有存活实例的总占用内存，单位：Byte
+     */
+    public long sumInstanceSize(Class<?> klass);
+
+    /**
+     * 获取某个实例的占用内存，单位：Byte
+     */
+    public long getInstanceSize(Object instance);
+
+    /**
+     * 统计某个class在jvm中当前所有存活实例的总个数
+     */
+    public long countInstances(Class<?> klass);
+
+    /**
+     * 获取所有已加载的类
+     */
+    public ArrayList<Class<?>> getAllLoadedClasses();
+}

arthas-vmtool/src/main/java/arthas/Vmtool.java

@@ -7,7 +7,7 @@ import java.util.ArrayList;
  * @author hengyunabc 2021-04-26
  * @since 3.5.1
  */
-public class Vmtool {
+public class Vmtool implements VMtoolMXBean {
 
     /**
      * 不要修改jni-lib的名称
@@ -41,39 +41,69 @@ public class Vmtool {
     /**
      * 检测jni-lib是否正常，如果正常，应该输出OK
      */
-    public static native String check();
+    private static native String check0();
 
     /**
      * 获取某个class在jvm中当前所有存活实例
      */
-    public static native <T> ArrayList<T> getInstances(Class<T> klass);
+    private static native <T> ArrayList<T> getInstances0(Class<T> klass);
 
     /**
      * 统计某个class在jvm中当前所有存活实例的总占用内存，单位：Byte
      */
-    public static native long sumInstanceSize(Class<?> klass);
+    private static native long sumInstanceSize0(Class<?> klass);
 
     /**
      * 获取某个实例的占用内存，单位：Byte
      */
-    public static native long getInstanceSize(Object instance);
+    private static native long getInstanceSize0(Object instance);
 
     /**
      * 统计某个class在jvm中当前所有存活实例的总个数
      */
-    public static native long countInstances(Class<?> klass);
+    private static native long countInstances0(Class<?> klass);
 
     /**
      * 获取所有已加载的类
      */
-    public static native ArrayList<Class<?>> getAllLoadedClasses();
+    private static native ArrayList<Class<?>> getAllLoadedClasses0();
 
     /**
      * 包括小类型(如int)
      */
     @SuppressWarnings("all")
     public static ArrayList<Class> getAllClasses() {
-        return getInstances(Class.class);
+        return getInstances0(Class.class);
+    }
+
+    @Override
+    public String check() {
+        return check0();
+    }
+
+    @Override
+    public <T> ArrayList<T> getInstances(Class<T> klass) {
+        return getInstances0(klass);
+    }
+
+    @Override
+    public long sumInstanceSize(Class<?> klass) {
+        return sumInstanceSize0(klass);
+    }
+
+    @Override
+    public long getInstanceSize(Object instance) {
+        return getInstanceSize0(instance);
+    }
+
+    @Override
+    public long countInstances(Class<?> klass) {
+        return countInstances0(klass);
+    }
+
+    @Override
+    public ArrayList<Class<?>> getAllLoadedClasses() {
+        return getAllLoadedClasses0();
     }
 
 }

arthas-vmtool/src/main/native/include/arthas_Vmtool.h

@@ -12,7 +12,7 @@ extern "C" {
  * Method:    check
  * Signature: ()Ljava/lang/String;
  */
-JNIEXPORT jstring JNICALL Java_arthas_Vmtool_check
+JNIEXPORT jstring JNICALL Java_arthas_Vmtool_check0
   (JNIEnv *, jclass);
 
 /*

arthas-vmtool/src/main/native/src/jni-library.cpp

@@ -6,7 +6,7 @@
 
 extern "C"
 JNIEXPORT jstring JNICALL
-Java_arthas_Vmtool_check(JNIEnv *env, jclass thisClass) {
+Java_arthas_Vmtool_check0(JNIEnv *env, jclass thisClass) {
     return env->NewStringUTF("OK");
 }
 
@@ -47,7 +47,7 @@ HeapObjectCallback(jlong class_tag, jlong size, jlong *tag_ptr, void *user_data)
 
 extern "C"
 JNIEXPORT jobject JNICALL
-Java_arthas_Vmtool_getInstances(JNIEnv *env, jclass thisClass, jclass klass) {
+Java_arthas_Vmtool_getInstances0(JNIEnv *env, jclass thisClass, jclass klass) {
 
     jvmtiEnv *jvmti = getJvmtiEnv(env);
 
@@ -88,7 +88,7 @@ Java_arthas_Vmtool_getInstances(JNIEnv *env, jclass thisClass, jclass klass) {
 
 extern "C"
 JNIEXPORT jlong JNICALL
-Java_arthas_Vmtool_sumInstanceSize(JNIEnv *env, jclass thisClass, jclass klass) {
+Java_arthas_Vmtool_sumInstanceSize0(JNIEnv *env, jclass thisClass, jclass klass) {
 
     jvmtiEnv *jvmti = getJvmtiEnv(env);
 
@@ -126,7 +126,7 @@ Java_arthas_Vmtool_sumInstanceSize(JNIEnv *env, jclass thisClass, jclass klass)
 }
 
 extern "C"
-JNIEXPORT jlong JNICALL Java_arthas_Vmtool_getInstanceSize
+JNIEXPORT jlong JNICALL Java_arthas_Vmtool_getInstanceSize0
         (JNIEnv *env, jclass thisClass, jobject instance) {
 
     jvmtiEnv *jvmti = getJvmtiEnv(env);
@@ -142,7 +142,7 @@ JNIEXPORT jlong JNICALL Java_arthas_Vmtool_getInstanceSize
 
 extern "C"
 JNIEXPORT jlong JNICALL
-Java_arthas_Vmtool_countInstances(JNIEnv *env, jclass thisClass, jclass klass) {
+Java_arthas_Vmtool_countInstances0(JNIEnv *env, jclass thisClass, jclass klass) {
 
     jvmtiEnv *jvmti = getJvmtiEnv(env);
 
@@ -172,7 +172,7 @@ Java_arthas_Vmtool_countInstances(JNIEnv *env, jclass thisClass, jclass klass) {
 }
 
 extern "C"
-JNIEXPORT jobject JNICALL Java_arthas_Vmtool_getAllLoadedClasses
+JNIEXPORT jobject JNICALL Java_arthas_Vmtool_getAllLoadedClasses0
         (JNIEnv *env, jclass thisClass) {
 
     jvmtiEnv *jvmti = getJvmtiEnv(env);

arthas-vmtool/src/test/java/arthas/VmtoolTest.java

@@ -28,27 +28,27 @@ public class VmtoolTest {
             System.err.println(path);
 
             String libPath = new File(path, System.mapLibraryName(Vmtool.JNI_LIBRARY_NAME)).getAbsolutePath();
-            Vmtool.getInstance(libPath);
+            Vmtool vmtool = Vmtool.getInstance(libPath);
 
             //调用native方法，获取已加载的类，不包括小类型(如int)
-            ArrayList<Class<?>> allLoadedClasses = Vmtool.getAllLoadedClasses();
+            ArrayList<Class<?>> allLoadedClasses = vmtool.getAllLoadedClasses();
             System.out.println("allLoadedClasses->" + allLoadedClasses.size());
 
             //通过下面的例子，可以看到getInstances(Class<T> klass)拿到的是当前存活的所有对象
             WeakReference<VmtoolTest> weakReference1 = new WeakReference<VmtoolTest>(new VmtoolTest());
             WeakReference<VmtoolTest> weakReference2 = new WeakReference<VmtoolTest>(new VmtoolTest());
             System.out.println(weakReference1.get() + " " + weakReference2.get());
-            ArrayList<Vmtool> beforeInstances = Vmtool.getInstances(Vmtool.class);
+            ArrayList<Vmtool> beforeInstances = vmtool.getInstances(Vmtool.class);
             System.out.println("before instances->" + beforeInstances);
-            System.out.println("size->" + Vmtool.getInstanceSize(weakReference1.get()));
-            System.out.println("count->" + Vmtool.countInstances(Vmtool.class));
-            System.out.println("sum size->" + Vmtool.sumInstanceSize(Vmtool.class));
+            System.out.println("size->" + vmtool.getInstanceSize(weakReference1.get()));
+            System.out.println("count->" + vmtool.countInstances(Vmtool.class));
+            System.out.println("sum size->" + vmtool.sumInstanceSize(Vmtool.class));
             beforeInstances = null;
 
             System.gc();
             Thread.sleep(100);
             System.out.println(weakReference1.get() + " " + weakReference2.get());
-            ArrayList<Vmtool> afterInstances = Vmtool.getInstances(Vmtool.class);
+            ArrayList<Vmtool> afterInstances = vmtool.getInstances(Vmtool.class);
             System.out.println("after instances->" + afterInstances);
         } catch (Exception e) {
             e.printStackTrace();