JVM MCP Server

Instructions

Implementation Reference

• src/jvm_mcp_server/server.py:386-452 (handler)

  The primary MCP tool handler for 'get_class_info', decorated with @self.mcp.tool(). Performs input validation (PID, max_matches), instantiates ClassInfoCoordinator, and invokes get_class_info_parallel.
  @self.mcp.tool() def get_class_info(pid: str = "", class_pattern: str = "", show_detail: bool = False, show_field: bool = False, use_regex: bool = False, depth: str = "", classloader_hash: Optional[str] = None, classloader_class: Optional[str] = None, max_matches: str = "") -> Dict: """获取类信息 - 使用jmap -histo和javap命令获取完整的类信息 Args: pid (str): 进程ID，使用字符串形式（如："12345"） class_pattern (str): 类名表达式匹配 show_detail (bool): 是否显示详细信息，默认false show_field (bool): 是否显示成员变量信息(需要show_detail=True)，默认false use_regex (bool): 是否使用正则表达式匹配，默认false depth (str): 属性遍历深度（暂未使用） classloader_hash (Optional[str]): 指定class的ClassLoader的hashcode（暂未使用） classloader_class (Optional[str]): 指定执行表达式的ClassLoader的class name（暂未使用） max_matches (str): 匹配类的最大数量，使用字符串形式（如："50"） Returns: Dict: 包含类信息的字典 """ # 验证 pid 参数 validated_pid = self._validate_and_convert_id(pid if pid else None, "Process ID") if validated_pid is None: return {"success": False, "error": "有效的进程ID是必须的"} # 验证 max_matches 参数 validated_max_matches = None if max_matches: validated_max_matches = self._validate_and_convert_id(max_matches, "Max matches") if validated_max_matches is None or validated_max_matches <= 0: return {"success": False, "error": "max_matches必须是正整数"} try: # 创建 ClassInfoCoordinator 实例 from .native.base import NativeCommandExecutor from .native.tools import ClassInfoCoordinator executor = NativeCommandExecutor() coordinator = ClassInfoCoordinator(executor) # 调用协调器获取类信息 result = coordinator.get_class_info_parallel( pid=str(validated_pid), class_pattern=class_pattern, show_detail=show_detail, show_field=show_field, use_regex=use_regex, max_matches=validated_max_matches ) return result except Exception as e: return { "success": False, "error": f"获取类信息时发生错误: {str(e)}", "classes": [], "total_matches": 0, "limited_by_max": False }
• src/jvm_mcp_server/native/tools/class_info.py:207-265 (helper)

  Core helper: get_class_info_parallel method in ClassInfoCoordinator. Used by handler. Handles parallel fetching of class structure info using ThreadPoolExecutor when show_detail=True, falls back to sequential otherwise.
  def get_class_info_parallel(self, pid: str, class_pattern: str = "", show_detail: bool = False, show_field: bool = False, use_regex: bool = False, max_matches: Optional[int] = None, max_workers: int = 5, **kwargs) -> Dict[str, Any]: """并行获取类信息（优化版本） Args: pid: 进程ID class_pattern: 类名模式匹配 show_detail: 是否显示详细信息 show_field: 是否显示字段信息 use_regex: 是否使用正则表达式匹配 max_matches: 最大匹配数量 max_workers: 最大工作线程数 Returns: Dict[str, Any]: 包含类信息的字典 """ if not show_detail: # 如果不需要详细信息，使用普通版本 return self.get_class_info( pid, class_pattern, show_detail, show_field, use_regex, max_matches, **kwargs ) try: # 第一步：获取基础信息 base_result = self.get_class_info( pid, class_pattern, False, False, use_regex, max_matches, **kwargs ) if not base_result.get('success', False): return base_result classes_info = base_result["classes"] # 第二步：并行获取结构信息 if classes_info: self._parallel_get_structure_info( classes_info, show_field, max_workers, **kwargs ) return { "success": True, "classes": classes_info, "total_matches": base_result["total_matches"], "limited_by_max": base_result["limited_by_max"], "error": None } except Exception as e: return { "success": False, "error": f"Parallel coordinator error: {str(e)}", "classes": [], "total_matches": 0, "limited_by_max": False }
• src/jvm_mcp_server/native/tools/class_info.py:25-108 (helper)

  Core helper: get_class_info method. Fetches runtime class histogram via jmap -histo, filters by pattern, optionally gets javap structure info, applies max_matches limit.
  def get_class_info(self, pid: str, class_pattern: str = "", show_detail: bool = False, show_field: bool = False, use_regex: bool = False, max_matches: Optional[int] = None, **kwargs) -> Dict[str, Any]: """获取类信息 Args: pid: 进程ID class_pattern: 类名模式匹配 show_detail: 是否显示详细信息 show_field: 是否显示字段信息 use_regex: 是否使用正则表达式匹配 max_matches: 最大匹配数量 Returns: Dict[str, Any]: 包含类信息的字典 """ try: # 第一步：使用 jmap -histo 获取运行时统计信息 jmap_result = self.jmap_histo_cmd.execute( pid=pid, operation=JmapOperation.HISTO, live_only=kwargs.get('live_only', False) ) if not jmap_result.get('success', False): return { "success": False, "error": f"Failed to get histogram data: {jmap_result.get('error', 'Unknown error')}", "classes": [], "total_matches": 0, "limited_by_max": False } # 第二步：提取和过滤类信息 histogram = jmap_result.get('histogram', []) filtered_classes = self._filter_classes(histogram, class_pattern, use_regex) # 第三步：应用最大匹配限制 limited_by_max = False if max_matches and len(filtered_classes) > max_matches: filtered_classes = filtered_classes[:max_matches] limited_by_max = True # 第四步：构建基础结果 classes_info = [] for class_data in filtered_classes: class_info = { "class_name": class_data["class_name"], "runtime_info": { "instances": class_data["instances"], "bytes": class_data["bytes"], "rank": len(classes_info) + 1 # 排名基于内存使用顺序 } } # 第五步：如果需要详细信息，获取结构信息 if show_detail: structure_info = self._get_structure_info( class_data["class_name"], show_field, **kwargs ) if structure_info: class_info["structure_info"] = structure_info classes_info.append(class_info) return { "success": True, "classes": classes_info, "total_matches": len(classes_info), "limited_by_max": limited_by_max, "error": None } except Exception as e: return { "success": False, "error": f"Coordinator error: {str(e)}", "classes": [], "total_matches": 0, "limited_by_max": False }