支持并发调用

arthas-beans/src/main/java/com/vdian/vclub/JvmUtils.java

@@ -6,8 +6,7 @@
 import java.util.ArrayList;
 
 /**
- * @author 1936978077@qq.com
- * @date 2021/02/12
+ * @author ZhangZiCheng 2021-02-12
  * @since 3.5.1
  */
 public class JvmUtils {
@@ -34,12 +33,12 @@ public class JvmUtils {
     /**
      * 获取某个class在jvm中当前所有存活实例
      */
-    public static synchronized native <T> ArrayList<T> getInstances(Class<T> klass);
+    public static native <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 static synchronized native long sumInstanceSize(Class<?> klass);
+    public static native long sumInstanceSize(Class<?> klass);
 
     /**
      * 获取某个实例的占用内存，单位：Byte
@@ -49,7 +48,7 @@ public class JvmUtils {
     /**
      * 统计某个class在jvm中当前所有存活实例的总个数
      */
-    public static synchronized native long countInstances(Class<?> klass);
+    public static native long countInstances(Class<?> klass);
 
     /**
      * 获取所有已加载的类

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

@@ -29,10 +29,19 @@ jobject createJavaInstance(JNIEnv *env, jclass javaClass) {
     return env->NewObject(javaClass, construct, "");
 }
 
+extern "C"
+jlong getClassHashCode(JNIEnv *env, jclass javaClass) {
+    //找到java类的hashCode方法
+    jmethodID hashCodeMethod = env->GetMethodID(javaClass, "hashCode", "()I");
+    //生成java类实例
+    return env->CallLongMethod(javaClass, hashCodeMethod);
+}
+
 extern "C"
 jvmtiIterationControl JNICALL
 HeapObjectCallback(jlong class_tag, jlong size, jlong *tag_ptr, void *user_data) {
-    *tag_ptr = 1;
+    auto *data = static_cast<jlong *>(user_data);
+    *tag_ptr = *data;
     return JVMTI_ITERATION_CONTINUE;
 }
 
@@ -49,15 +58,15 @@ Java_com_vdian_vclub_JvmUtils_getInstances(JNIEnv *env, jclass thisClass, jclass
         printf("ERROR: JVMTI AddCapabilities failed!%u\n", error);
         return JNI_FALSE;
     }
-    //todo 支持并发调用
+    //这里用hashCode作为标记
+    jlong tag = getClassHashCode(env, klass);
     error = jvmti->IterateOverInstancesOfClass(klass, JVMTI_HEAP_OBJECT_EITHER,
-                                               HeapObjectCallback, NULL);
+                                               HeapObjectCallback, &tag);
     if (error) {
         printf("ERROR: JVMTI IterateOverInstancesOfClass failed!%u\n", error);
         return JNI_FALSE;
     }
 
-    jlong tag = 1;
     jint count = 0;
     jobject *instances;
     error = jvmti->GetObjectsWithTags(1, &tag, &count, &instances, NULL);
@@ -90,15 +99,15 @@ Java_com_vdian_vclub_JvmUtils_sumInstanceSize(JNIEnv *env, jclass thisClass, jcl
         printf("ERROR: JVMTI AddCapabilities failed!%u\n", error);
         return JNI_FALSE;
     }
-    //todo 支持并发调用
+    //这里用hashCode作为标记
+    jlong tag = getClassHashCode(env, klass);
     error = jvmti->IterateOverInstancesOfClass(klass, JVMTI_HEAP_OBJECT_EITHER,
-                                               HeapObjectCallback, NULL);
+                                               HeapObjectCallback, &tag);
     if (error) {
         printf("ERROR: JVMTI IterateOverInstancesOfClass failed!%u\n", error);
         return JNI_FALSE;
     }
 
-    jlong tag = 1;
     jint count = 0;
     jobject *instances;
     error = jvmti->GetObjectsWithTags(1, &tag, &count, &instances, NULL);
@@ -144,15 +153,15 @@ Java_com_vdian_vclub_JvmUtils_countInstances(JNIEnv *env, jclass thisClass, jcla
         printf("ERROR: JVMTI AddCapabilities failed!%u\n", error);
         return JNI_FALSE;
     }
-    //todo 支持并发调用
+    //这里用hashCode作为标记
+    jlong tag = getClassHashCode(env, klass);
     error = jvmti->IterateOverInstancesOfClass(klass, JVMTI_HEAP_OBJECT_EITHER,
-                                               HeapObjectCallback, NULL);
+                                               HeapObjectCallback, &tag);
     if (error) {
         printf("ERROR: JVMTI IterateOverInstancesOfClass failed!%u\n", error);
         return JNI_FALSE;
     }
 
-    jlong tag = 1;
     jint count = 0;
     error = jvmti->GetObjectsWithTags(1, &tag, &count, NULL, NULL);
     if (error) {