解决DispatchMapping[XXX] does not define a handler property

本文列举了Struts框架中常见的错误及其原因,并提供了详细的解决步骤。包括配置问题、表单验证失败、方法调用错误等,适用于开发者快速定位并解决问题。
错误 :javax.servlet.ServletException: DispatchMapping[0] does not define a handler property 
原因: action参数配置不全 
解决方法:在 config文件中 添加 parameter="method"等 

错误: 表单数据验证失败时发生错误,“No input attribute for mapping path” 
原因:action中表单验证 validate="true" ,如果validate()返回非空的ActionErrors,将会被转到input属性指定的URI,而action中未指定input时会报此错 
解决方法:添加 input="url" 或者 validate="false" 

错误:jsp页面中,一个form有隐藏的method属性,<input type="hidden" name="method" value="<bean:message key="button.deleteall"/>"> ,当其他的button使用 method时会默认为使用该属性,则达不到程序员预期的操作 
解决方法:实用javascript写一个function,改变该method值 
function{ 
document.forms[0].elements.value="你要的操作名"; 

} 

错误:Action里无法解析 导入的包,Form里的方法,但是代码没错 
原因:不明,我是改变了validation.xml后重新发布而出了错的 
解决方法:将工程关了,再打开,myeclipse会将工程重新构建,这样问题就解决了 
ps:重启Tomcat是没有用滴……

错误:Struts:HTTP Status 404 - Servlet action is not available

   原因 1.、web.xml文件中未配置ActionServlet。      
   2、struts-config.xml文件未配置你要访问的Action。   
    3、你的jsp文件form标记中action属性的路径名称错误。   
    4、非以上三种情况。

针对以上4种情况相应的解决方案如下:   
    
   1、在web.xml文件中加上ActionServlet的配置信息   
    
   <servlet>   
           <servlet-name>action</servlet-name>   
           <servlet-class>org.apache.struts.action.ActionServlet</servlet-class>   
           <init-param>   
               <param-name>config</param-name>   
               <param-value>/WEB-INF/struts-config.xml</param-value>   
           </init-param>   
           <init-param>   
               <param-name>debug</param-name>   
               <param-value>0</param-value>   
           </init-param>   
           <init-param>   
               <param-name>detail</param-name>   
               <param-value>0</param-value>   
           </init-param>   
           <load-on-startup>2</load-on-startup>   
       </servlet>       
    
   2、在struts-config.xml文件检查你要访问的Action配置文件。   
    
   3、检查jsp文件form标记中action属性的路径名称是否与struts-config.xml文件中action标记的path属性的路径名称一致

 

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[{ "resource": "/e:/esp32/esp32_spi_slave_transfer_Prj (3)/src/BLE_master.cpp", "owner": "cpp", "severity": 8, "message": "'class NimBLEScan' has no member named 'setAdvertisedDeviceCallbacks'", "startLineNumber": 30, "startColumn": 12, "endLineNumber": 30, "endColumn": 12 },{ "resource": "/e:/esp32/esp32_spi_slave_transfer_Prj (3)/src/BLE_master.cpp", "owner": "cpp", "severity": 8, "message": "'getClientListSize' is not a member of 'NimBLEDevice'", "startLineNumber": 40, "startColumn": 36, "endLineNumber": 40, "endColumn": 36 },{ "resource": "/e:/esp32/esp32_spi_slave_transfer_Prj (3)/src/BLE_master.cpp", "owner": "cpp", "severity": 8, "message": "'getClientByID' is not a member of 'NimBLEDevice'", "startLineNumber": 41, "startColumn": 39, "endLineNumber": 41, "endColumn": 39 },{ "resource": "/e:/esp32/esp32_spi_slave_transfer_Prj (3)/src/BLE_master.cpp", "owner": "cpp", "severity": 8, "message": "'class NimBLERemoteCharacteristic' has no member named 'setNotifyCallback'; did you mean 'm_notifyCallback'?", "startLineNumber": 98, "startColumn": 36, "endLineNumber": 98, "endColumn": 36 },{ "resource": "/e:/esp32/esp32_spi_slave_transfer_Prj (3)/src/BLE_master.cpp", "owner": "cpp", "severity": 8, "message": "no match for 'operator==' (operand types are 'std::__cxx11::string' {aka 'std::__cxx11::basic_string<char>'} and 'String')", "startLineNumber": 127, "startColumn": 36, "endLineNumber": 127, "endColumn": 36 }] [{ "resource": "/e:/esp32/esp32_spi_slave_transfer_Prj (3)/src/BLE_master.h", "owner": "cpp", "severity": 8, "message": "'void BLEMaster::AdvertisedDeviceCallback::onResult(NimBLEAdvertisedDevice)' marked 'override', but does not override", "startLineNumber": 26, "startColumn": 14, "endLineNumber": 26, "endColumn": 14 }] /* * Copyright 2020-2025 Ryan Powell <ryan@nable-embedded.io> and * esp-nimble-cpp, NimBLE-Arduino contributors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #ifndef NIMBLE_CPP_DEVICE_H_ #define NIMBLE_CPP_DEVICE_H_ #include "nimconfig.h" #if CONFIG_BT_ENABLED # ifdef ESP_PLATFORM # ifndef CONFIG_IDF_TARGET_ESP32P4 # include <esp_bt.h> # endif # endif # if defined(CONFIG_NIMBLE_CPP_IDF) # include <host/ble_gap.h> # else # include <nimble/nimble/host/include/host/ble_gap.h> # endif /**** FIX COMPILATION ****/ # undef min # undef max /**************************/ # include <string> # include <vector> # if CONFIG_BT_NIMBLE_ROLE_CENTRAL # include <array> class NimBLEClient; # endif # if CONFIG_BT_NIMBLE_ROLE_OBSERVER class NimBLEScan; # endif # if CONFIG_BT_NIMBLE_ROLE_BROADCASTER # if CONFIG_BT_NIMBLE_EXT_ADV class NimBLEExtAdvertising; # else class NimBLEAdvertising; # endif # endif # if CONFIG_BT_NIMBLE_ROLE_PERIPHERAL class NimBLEServer; # if CONFIG_BT_NIMBLE_L2CAP_COC_MAX_NUM > 0 class NimBLEL2CAPServer; # endif # endif # if CONFIG_BT_NIMBLE_ROLE_PERIPHERAL || CONFIG_BT_NIMBLE_ROLE_CENTRAL class NimBLEConnInfo; # endif class NimBLEAddress; class NimBLEDeviceCallbacks; # define BLEDevice NimBLEDevice # define BLEClient NimBLEClient # define BLERemoteService NimBLERemoteService # define BLERemoteCharacteristic NimBLERemoteCharacteristic # define BLERemoteDescriptor NimBLERemoteDescriptor # define BLEAdvertisedDevice NimBLEAdvertisedDevice # define BLEScan NimBLEScan # define BLEUUID NimBLEUUID # define BLEAddress NimBLEAddress # define BLEUtils NimBLEUtils # define BLEClientCallbacks NimBLEClientCallbacks # define BLEAdvertisedDeviceCallbacks NimBLEScanCallbacks # define BLEScanResults NimBLEScanResults # define BLEServer NimBLEServer # define BLEService NimBLEService # define BLECharacteristic NimBLECharacteristic # define BLEAdvertising NimBLEAdvertising # define BLEServerCallbacks NimBLEServerCallbacks # define BLECharacteristicCallbacks NimBLECharacteristicCallbacks # define BLEAdvertisementData NimBLEAdvertisementData # define BLEDescriptor NimBLEDescriptor # define BLE2904 NimBLE2904 # define BLEDescriptorCallbacks NimBLEDescriptorCallbacks # define BLEBeacon NimBLEBeacon # define BLEEddystoneTLM NimBLEEddystoneTLM # define BLEEddystoneURL NimBLEEddystoneURL # define BLEConnInfo NimBLEConnInfo # define BLEL2CAPServer NimBLEL2CAPServer # define BLEL2CAPService NimBLEL2CAPService # define BLEL2CAPServiceCallbacks NimBLEL2CAPServiceCallbacks # define BLEL2CAPClient NimBLEL2CAPClient # define BLEL2CAPClientCallbacks NimBLEL2CAPClientCallbacks # define BLEL2CAPChannel NimBLEL2CAPChannel # define BLEL2CAPChannelCallbacks NimBLEL2CAPChannelCallbacks # ifdef CONFIG_BT_NIMBLE_MAX_CONNECTIONS # define NIMBLE_MAX_CONNECTIONS CONFIG_BT_NIMBLE_MAX_CONNECTIONS # else # define NIMBLE_MAX_CONNECTIONS CONFIG_NIMBLE_MAX_CONNECTIONS # endif enum class NimBLETxPowerType { All = 0, Advertise = 1, Scan = 2, Connection = 3 }; typedef int (*gap_event_handler)(ble_gap_event* event, void* arg); /** * @brief A model of a BLE Device from which all the BLE roles are created. */ class NimBLEDevice { public: static bool init(const std::string& deviceName); static bool deinit(bool clearAll = false); static bool setDeviceName(const std::string& deviceName); static bool isInitialized(); static NimBLEAddress getAddress(); static std::string toString(); static bool whiteListAdd(const NimBLEAddress& address); static bool whiteListRemove(const NimBLEAddress& address); static bool onWhiteList(const NimBLEAddress& address); static size_t getWhiteListCount(); static NimBLEAddress getWhiteListAddress(size_t index); static bool setOwnAddrType(uint8_t type); static bool setOwnAddr(const NimBLEAddress& addr); static bool setOwnAddr(const uint8_t* addr); static void setDeviceCallbacks(NimBLEDeviceCallbacks* cb); static void setScanDuplicateCacheSize(uint16_t cacheSize); static void setScanFilterMode(uint8_t type); static void setScanDuplicateCacheResetTime(uint16_t time); static bool setCustomGapHandler(gap_event_handler handler); static void setSecurityAuth(bool bonding, bool mitm, bool sc); static void setSecurityAuth(uint8_t auth); static void setSecurityIOCap(uint8_t iocap); static void setSecurityInitKey(uint8_t initKey); static void setSecurityRespKey(uint8_t respKey); static void setSecurityPasskey(uint32_t passKey); static uint32_t getSecurityPasskey(); static bool startSecurity(uint16_t connHandle, int* rcPtr = nullptr); static bool setMTU(uint16_t mtu); static uint16_t getMTU(); static void onReset(int reason); static void onSync(void); static void host_task(void* param); static int getPower(NimBLETxPowerType type = NimBLETxPowerType::All); static bool setPower(int8_t dbm, NimBLETxPowerType type = NimBLETxPowerType::All); static bool setDefaultPhy(uint8_t txPhyMask, uint8_t rxPhyMask); # ifdef ESP_PLATFORM # ifndef CONFIG_IDF_TARGET_ESP32P4 static esp_power_level_t getPowerLevel(esp_ble_power_type_t powerType = ESP_BLE_PWR_TYPE_DEFAULT); static bool setPowerLevel(esp_power_level_t powerLevel, esp_ble_power_type_t powerType = ESP_BLE_PWR_TYPE_DEFAULT); # endif # endif # if CONFIG_BT_NIMBLE_ROLE_OBSERVER static NimBLEScan* getScan(); # endif # if CONFIG_BT_NIMBLE_ROLE_PERIPHERAL static NimBLEServer* createServer(); static NimBLEServer* getServer(); # if CONFIG_BT_NIMBLE_L2CAP_COC_MAX_NUM > 0 static NimBLEL2CAPServer* createL2CAPServer(); static NimBLEL2CAPServer* getL2CAPServer(); # endif # endif # if CONFIG_BT_NIMBLE_ROLE_PERIPHERAL || CONFIG_BT_NIMBLE_ROLE_CENTRAL static bool injectConfirmPasskey(const NimBLEConnInfo& peerInfo, bool accept); static bool injectPassKey(const NimBLEConnInfo& peerInfo, uint32_t pin); # endif # if CONFIG_BT_NIMBLE_ROLE_BROADCASTER # if CONFIG_BT_NIMBLE_EXT_ADV static NimBLEExtAdvertising* getAdvertising(); static bool startAdvertising(uint8_t instId, int duration = 0, int maxEvents = 0); static bool stopAdvertising(uint8_t instId); static bool stopAdvertising(); # endif # if !CONFIG_BT_NIMBLE_EXT_ADV || defined(_DOXYGEN_) static NimBLEAdvertising* getAdvertising(); static bool startAdvertising(uint32_t duration = 0); static bool stopAdvertising(); # endif # endif # if CONFIG_BT_NIMBLE_ROLE_CENTRAL static NimBLEClient* createClient(); static NimBLEClient* createClient(const NimBLEAddress& peerAddress); static bool deleteClient(NimBLEClient* pClient); static NimBLEClient* getClientByHandle(uint16_t connHandle); static NimBLEClient* getClientByPeerAddress(const NimBLEAddress& peerAddress); static NimBLEClient* getDisconnectedClient(); static size_t getCreatedClientCount(); static std::vector<NimBLEClient*> getConnectedClients(); # endif # if CONFIG_BT_NIMBLE_ROLE_CENTRAL || CONFIG_BT_NIMBLE_ROLE_PERIPHERAL static bool deleteBond(const NimBLEAddress& address); static int getNumBonds(); static bool isBonded(const NimBLEAddress& address); static bool deleteAllBonds(); static NimBLEAddress getBondedAddress(int index); # endif private: static bool m_synced; static bool m_initialized; static uint32_t m_passkey; static ble_gap_event_listener m_listener; static uint8_t m_ownAddrType; static std::vector<NimBLEAddress> m_whiteList; static NimBLEDeviceCallbacks* m_pDeviceCallbacks; static NimBLEDeviceCallbacks defaultDeviceCallbacks; # if CONFIG_BT_NIMBLE_ROLE_OBSERVER static NimBLEScan* m_pScan; # endif # if CONFIG_BT_NIMBLE_ROLE_PERIPHERAL static NimBLEServer* m_pServer; # if CONFIG_BT_NIMBLE_L2CAP_COC_MAX_NUM > 0 static NimBLEL2CAPServer* m_pL2CAPServer; # endif # endif # if CONFIG_BT_NIMBLE_ROLE_BROADCASTER # if CONFIG_BT_NIMBLE_EXT_ADV static NimBLEExtAdvertising* m_bleAdvertising; # else static NimBLEAdvertising* m_bleAdvertising; # endif # endif # if CONFIG_BT_NIMBLE_ROLE_CENTRAL static std::array<NimBLEClient*, NIMBLE_MAX_CONNECTIONS> m_pClients; # endif # ifdef ESP_PLATFORM # if CONFIG_BTDM_BLE_SCAN_DUPL || CONFIG_BT_LE_SCAN_DUPL static uint16_t m_scanDuplicateSize; static uint8_t m_scanFilterMode; static uint16_t m_scanDuplicateResetTime; # endif # endif # if CONFIG_BT_NIMBLE_ROLE_CENTRAL friend class NimBLEClient; # endif # if CONFIG_BT_NIMBLE_ROLE_OBSERVER friend class NimBLEScan; # endif # if CONFIG_BT_NIMBLE_ROLE_PERIPHERAL friend class NimBLEServer; friend class NimBLECharacteristic; # endif # if CONFIG_BT_NIMBLE_ROLE_BROADCASTER friend class NimBLEAdvertising; # if CONFIG_BT_NIMBLE_EXT_ADV friend class NimBLEExtAdvertising; friend class NimBLEExtAdvertisement; # endif # endif }; # if CONFIG_BT_NIMBLE_ROLE_CENTRAL # include "NimBLEClient.h" # include "NimBLERemoteService.h" # include "NimBLERemoteCharacteristic.h" # include "NimBLERemoteDescriptor.h" # endif # if CONFIG_BT_NIMBLE_ROLE_OBSERVER # include "NimBLEScan.h" # endif # if CONFIG_BT_NIMBLE_ROLE_PERIPHERAL # include "NimBLEServer.h" # include "NimBLEService.h" # include "NimBLECharacteristic.h" # include "NimBLEDescriptor.h" # if CONFIG_BT_NIMBLE_L2CAP_COC_MAX_NUM # include "NimBLEL2CAPServer.h" # include "NimBLEL2CAPChannel.h" # endif # endif # if CONFIG_BT_NIMBLE_ROLE_BROADCASTER # if CONFIG_BT_NIMBLE_EXT_ADV # include "NimBLEExtAdvertising.h" # else # include "NimBLEAdvertising.h" # endif # endif # if CONFIG_BT_NIMBLE_ROLE_CENTRAL || CONFIG_BT_NIMBLE_ROLE_PERIPHERAL # include "NimBLEConnInfo.h" # endif # include "NimBLEAddress.h" # include "NimBLEUtils.h" /** * @brief Callbacks associated with a BLE device. */ class NimBLEDeviceCallbacks { public: virtual ~NimBLEDeviceCallbacks() {}; /** * @brief Indicates an inability to perform a store operation. * This callback should do one of two things: * -Address the problem and return 0, indicating that the store operation * should proceed. * -Return nonzero to indicate that the store operation should be aborted. * @param event Describes the store event being reported. * BLE_STORE_EVENT_FULL; or * BLE_STORE_EVENT_OVERFLOW * @return 0 if the store operation should proceed; * nonzero if the store operation should be aborted. */ virtual int onStoreStatus(struct ble_store_status_event* event, void* arg); }; #endif // CONFIG_BT_ENABLED #endif // NIMBLE_CPP_DEVICE_H_ /* * Copyright 2020-2025 Ryan Powell <ryan@nable-embedded.io> and * esp-nimble-cpp, NimBLE-Arduino contributors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #ifndef NIMBLE_CPP_SCAN_H_ #define NIMBLE_CPP_SCAN_H_ #include "nimconfig.h" #if CONFIG_BT_ENABLED && CONFIG_BT_NIMBLE_ROLE_OBSERVER # include "NimBLEAdvertisedDevice.h" # include "NimBLEUtils.h" # if defined(CONFIG_NIMBLE_CPP_IDF) # include "host/ble_gap.h" # else # include "nimble/nimble/host/include/host/ble_gap.h" # endif # include <vector> class NimBLEDevice; class NimBLEScan; class NimBLEAdvertisedDevice; class NimBLEScanCallbacks; class NimBLEAddress; /** * @brief A class that contains and operates on the results of a BLE scan. * @details When a scan completes, we have a set of found devices. Each device is described * by a NimBLEAdvertisedDevice object. The number of items in the set is given by * getCount(). We can retrieve a device by calling getDevice() passing in the * index (starting at 0) of the desired device. */ class NimBLEScanResults { public: void dump() const; int getCount() const; const NimBLEAdvertisedDevice* getDevice(uint32_t idx) const; const NimBLEAdvertisedDevice* getDevice(const NimBLEAddress& address) const; std::vector<NimBLEAdvertisedDevice*>::const_iterator begin() const; std::vector<NimBLEAdvertisedDevice*>::const_iterator end() const; private: friend NimBLEScan; std::vector<NimBLEAdvertisedDevice*> m_deviceVec; }; /** * @brief Perform and manage %BLE scans. * * Scanning is associated with a %BLE client that is attempting to locate BLE servers. */ class NimBLEScan { public: bool start(uint32_t duration, bool isContinue = false, bool restart = true); bool isScanning(); void setScanCallbacks(NimBLEScanCallbacks* pScanCallbacks, bool wantDuplicates = false); void setActiveScan(bool active); void setInterval(uint16_t intervalMs); void setWindow(uint16_t windowMs); void setDuplicateFilter(uint8_t enabled); void setLimitedOnly(bool enabled); void setFilterPolicy(uint8_t filter); bool stop(); void clearResults(); NimBLEScanResults getResults(); NimBLEScanResults getResults(uint32_t duration, bool is_continue = false); void setMaxResults(uint8_t maxResults); void erase(const NimBLEAddress& address); void erase(const NimBLEAdvertisedDevice* device); # if CONFIG_BT_NIMBLE_EXT_ADV enum Phy { SCAN_1M = 0x01, SCAN_CODED = 0x02, SCAN_ALL = 0x03 }; void setPhy(Phy phyMask); void setPeriod(uint32_t periodMs); # endif private: friend class NimBLEDevice; NimBLEScan(); ~NimBLEScan(); static int handleGapEvent(ble_gap_event* event, void* arg); void onHostSync(); NimBLEScanCallbacks* m_pScanCallbacks; ble_gap_disc_params m_scanParams; NimBLEScanResults m_scanResults; NimBLETaskData* m_pTaskData; uint8_t m_maxResults; # if CONFIG_BT_NIMBLE_EXT_ADV uint8_t m_phy{SCAN_ALL}; uint16_t m_period{0}; # endif }; /** * @brief A callback handler for callbacks associated device scanning. */ class NimBLEScanCallbacks { public: virtual ~NimBLEScanCallbacks() {} /** * @brief Called when a new device is discovered, before the scan result is received (if applicable). * @param [in] advertisedDevice The device which was discovered. */ virtual void onDiscovered(const NimBLEAdvertisedDevice* advertisedDevice); /** * @brief Called when a new scan result is complete, including scan response data (if applicable). * @param [in] advertisedDevice The device for which the complete result is available. */ virtual void onResult(const NimBLEAdvertisedDevice* advertisedDevice); /** * @brief Called when a scan operation ends. * @param [in] scanResults The results of the scan that ended. * @param [in] reason The reason code for why the scan ended. */ virtual void onScanEnd(const NimBLEScanResults& scanResults, int reason); }; #endif // CONFIG_BT_ENABLED CONFIG_BT_NIMBLE_ROLE_OBSERVER #endif // NIMBLE_CPP_SCAN_H_ /* * Copyright 2020-2025 Ryan Powell <ryan@nable-embedded.io> and * esp-nimble-cpp, NimBLE-Arduino contributors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #ifndef NIMBLE_CPP_ADVERTISED_DEVICE_H_ #define NIMBLE_CPP_ADVERTISED_DEVICE_H_ #include "nimconfig.h" #if CONFIG_BT_ENABLED && CONFIG_BT_NIMBLE_ROLE_OBSERVER # include "NimBLEAddress.h" # include "NimBLEScan.h" # include "NimBLEUUID.h" # if defined(CONFIG_NIMBLE_CPP_IDF) # include "host/ble_hs_adv.h" # include "host/ble_gap.h" # else # include "nimble/nimble/host/include/host/ble_hs_adv.h" # include "nimble/nimble/host/include/host/ble_gap.h" # endif # include <vector> class NimBLEScan; /** * @brief A representation of a %BLE advertised device found by a scan. * * When we perform a %BLE scan, the result will be a set of devices that are advertising. This * class provides a model of a detected device. */ class NimBLEAdvertisedDevice { public: NimBLEAdvertisedDevice() = default; uint8_t getAdvType() const; uint8_t getAdvFlags() const; uint16_t getAppearance() const; uint16_t getAdvInterval() const; uint16_t getMinInterval() const; uint16_t getMaxInterval() const; uint8_t getManufacturerDataCount() const; const NimBLEAddress& getAddress() const; std::string getManufacturerData(uint8_t index = 0) const; std::string getURI() const; std::string getPayloadByType(uint16_t type, uint8_t index = 0) const; std::string getName() const; int8_t getRSSI() const; NimBLEScan* getScan() const; uint8_t getServiceDataCount() const; std::string getServiceData(uint8_t index = 0) const; std::string getServiceData(const NimBLEUUID& uuid) const; NimBLEUUID getServiceDataUUID(uint8_t index = 0) const; NimBLEUUID getServiceUUID(uint8_t index = 0) const; uint8_t getServiceUUIDCount() const; NimBLEAddress getTargetAddress(uint8_t index = 0) const; uint8_t getTargetAddressCount() const; int8_t getTXPower() const; uint16_t getAdvLength() const; uint8_t getAddressType() const; bool isAdvertisingService(const NimBLEUUID& uuid) const; bool haveAppearance() const; bool haveManufacturerData() const; bool haveName() const; bool haveServiceData() const; bool haveServiceUUID() const; bool haveTXPower() const; bool haveConnParams() const; bool haveAdvInterval() const; bool haveTargetAddress() const; bool haveURI() const; bool haveType(uint16_t type) const; std::string toString() const; bool isConnectable() const; bool isScannable() const; bool isLegacyAdvertisement() const; # if CONFIG_BT_NIMBLE_EXT_ADV uint8_t getSetId() const; uint8_t getPrimaryPhy() const; uint8_t getSecondaryPhy() const; uint16_t getPeriodicInterval() const; uint8_t getDataStatus() const; # endif operator NimBLEAddress() const; const std::vector<uint8_t>& getPayload() const; const std::vector<uint8_t>::const_iterator begin() const; const std::vector<uint8_t>::const_iterator end() const; /** * @brief A template to convert the service data to <type\>. * @tparam T The type to convert the data to. * @param [in] skipSizeCheck If true it will skip checking if the data size is less than <tt>sizeof(<type\>)</tt>. * @return The data converted to <type\> or NULL if skipSizeCheck is false and the data is * less than <tt>sizeof(<type\>)</tt>. * @details <b>Use:</b> <tt>getManufacturerData<type>(skipSizeCheck);</tt> */ template <typename T> T getManufacturerData(bool skipSizeCheck = false) const { std::string data = getManufacturerData(); if (!skipSizeCheck && data.size() < sizeof(T)) return T(); const char* pData = data.data(); return *((T*)pData); } /** * @brief A template to convert the service data to <tt><type\></tt>. * @tparam T The type to convert the data to. * @param [in] index The vector index of the service data requested. * @param [in] skipSizeCheck If true it will skip checking if the data size is less than <tt>sizeof(<type\>)</tt>. * @return The data converted to <type\> or NULL if skipSizeCheck is false and the data is * less than <tt>sizeof(<type\>)</tt>. * @details <b>Use:</b> <tt>getServiceData<type>(skipSizeCheck);</tt> */ template <typename T> T getServiceData(uint8_t index = 0, bool skipSizeCheck = false) const { std::string data = getServiceData(index); if (!skipSizeCheck && data.size() < sizeof(T)) return T(); const char* pData = data.data(); return *((T*)pData); } /** * @brief A template to convert the service data to <tt><type\></tt>. * @tparam T The type to convert the data to. * @param [in] uuid The uuid of the service data requested. * @param [in] skipSizeCheck If true it will skip checking if the data size is less than <tt>sizeof(<type\>)</tt>. * @return The data converted to <type\> or NULL if skipSizeCheck is false and the data is * less than <tt>sizeof(<type\>)</tt>. * @details <b>Use:</b> <tt>getServiceData<type>(skipSizeCheck);</tt> */ template <typename T> T getServiceData(const NimBLEUUID& uuid, bool skipSizeCheck = false) const { std::string data = getServiceData(uuid); if (!skipSizeCheck && data.size() < sizeof(T)) return T(); const char* pData = data.data(); return *((T*)pData); } private: friend class NimBLEScan; NimBLEAdvertisedDevice(const ble_gap_event* event, uint8_t eventType); void update(const ble_gap_event* event, uint8_t eventType); uint8_t findAdvField(uint8_t type, uint8_t index = 0, size_t* data_loc = nullptr) const; size_t findServiceData(uint8_t index, uint8_t* bytes) const; NimBLEAddress m_address{}; uint8_t m_advType{}; int8_t m_rssi{}; uint8_t m_callbackSent{}; uint16_t m_advLength{}; # if CONFIG_BT_NIMBLE_EXT_ADV bool m_isLegacyAdv{}; uint8_t m_dataStatus{}; uint8_t m_sid{}; uint8_t m_primPhy{}; uint8_t m_secPhy{}; uint16_t m_periodicItvl{}; # endif std::vector<uint8_t> m_payload; }; #endif /* CONFIG_BT_ENABLED && CONFIG_BT_NIMBLE_ROLE_OBSERVER */ #endif /* NIMBLE_CPP_ADVERTISED_DEVICE_H_ */
10-14
<think>我们正在解决的是在C++中使用命名空间时出现的"XXX does not name a type"错误。根据用户提供的引用和之前的上下文,这个错误通常是由于类型声明不完整或使用方式不正确导致的。以下将结合引用内容分析原因并提供解决方案。 ### 错误原因分析 1. **类型未完全定义**(引用[3]) 当在命名空间中使用一个类型(如结构体)时,如果该类型仅是前置声明而未定义完整,编译器会报告"does not name a type"。例如: ```cpp namespace MySpace { struct Point; // 前置声明 } // 错误:Point类型不完整 MySpace::Point p; ``` 2. **循环依赖**(引用[1]) 两个头文件互相包含可能导致类型定义顺序错乱: ```cpp // a.h #include "b.h" namespace A { struct X { B::Y y; }; // 需要B::Y的定义 } // b.h #include "a.h" namespace B { struct Y { A::X x; }; // 依赖A::X的定义 -> 循环依赖 } ``` 3. **违反ODR(单一定义规则)** 同一命名空间下的类型在不同文件中定义不一致会导致未定义行为。 4. **命名空间作用域错误** 使用类型时未正确限定命名空间: ```cpp namespace MySpace { struct Point { int x, y; }; } Point p; // 错误:全局作用域无Point类型 ``` 5. **在类定义外部修改变量**(引用[4]) 在类作用域内进行非声明操作(如函数调用)会导致编译器将语句误解为类型声明: ```cpp class Test { std::vector<int> v; v.push_back(1); // 错误:v不是类型名 }; ``` ### 解决方案 #### ✅ 方案1: 确保类型完整定义(针对原因1) - **头文件(a.h)中提供完整定义**: ```cpp // a.h #ifndef A_HEADER #define A_HEADER namespace MySpace { struct Point { // 完整定义 int x; int y; }; } #endif ``` - **使用处包含头文件**(b.cpp): ```cpp #include "a.h" void func() { MySpace::Point p{1, 2}; // 正确:类型已完整定义 } ``` #### ✅ 方案2: 打破循环依赖(针对原因2) - **使用前置声明和指针**: ```cpp // a.h(不包含b.h) namespace B { struct Y; } // 前置声明 namespace A { struct X { B::Y* y_ptr; // 使用指针(不要求Y完整定义) }; } // b.h(不包含a.h) namespace A { struct X; } // 前置声明 namespace B { struct Y { A::X* x_ptr; }; } ``` #### ✅ 方案3: 检查ODR一致性 - 确保所有文件中同一命名空间下的同名结构体定义完全相同(成员顺序、类型一致)。 #### ✅ 方案4: 正确限定命名空间(针对原因4) ```cpp // 正确使用方式1:显式限定 MySpace::Point p1; // 正确使用方式2:using声明 using MySpace::Point; Point p2; // 正确使用方式3:using指令(谨慎使用) using namespace MySpace; Point p3; ``` #### ✅ 方案5: 类作用域内禁止非声明操作(针对原因5) - 初始化成员变量应使用构造函数: ```cpp class Test { std::vector<int> v; public: Test() : v{1} { } // 构造函数初始化 // 或在函数内操作: void init() { v.push_back(1); } }; ``` ### 错误示例修正演示 #### 错误代码示例 ```cpp // a.h namespace NS { struct Data; // 仅声明(不完整类型) } // b.cpp #include "a.h" void foo() { NS::Data d; // 错误:'NS::Data' does not name a type } ``` #### 修正后代码 ```cpp // a.h namespace NS { struct Data { // 提供完整定义 int value; }; } // b.cpp #include "a.h" void foo() { NS::Data d{42}; // 正确 } ``` ### 编译链接注意事项 1. **头文件包含顺序** 确保使用类型前其定义已被包含(如b.cpp中`#include "a.h"`必须位于所有代码之前)。 2. **命名空间别名** 使用别名时仍需原始命名空间存在: ```cpp namespace Short = VeryLongNamespaceName; Short::MyStruct s; // 依赖VeryLongNamespaceName::MyStruct的定义 ``` §§相关问题§§ 1. C++中如何使用前置声明减少编译依赖? 2. 如何避免C++头文件循环引用问题? 3. C++的ODR规则具体包含哪些要求? 4. 在命名空间中定义全局常量有哪些注意事项?[^1] 5. 类成员初始化有哪些现代C++语法?[^4] [^1]: 全局作用域中常量对象的初始化规则[^1] [^3]: 类型不完整导致的成员定义错误[^3] [^4]: 类作用域内非声明语句导致的类型错误[^4] </think>### 解决命名空间 "XXX does not name a type" 错误 在 C++ 中使用命名空间时出现 `"XXX" does not name a type` 错误,通常有以下原因和解决方案: --- #### ️ 原因 1:缺少头文件包含 **问题**:未包含定义命名空间和类型的头文件 **解决方案**: 1. 确保在使用类型的文件中包含定义文件 2. 检查头文件路径是否正确 ```cpp // b.cpp(使用文件) #include "a.h" // 必须包含定义命名空间的文件 void example() { XXX::MyStruct s; // 正确使用命名空间中的类型 } ``` --- #### 🔄 原因 2:循环依赖(常见陷阱) **问题**:头文件相互包含导致类型定义顺序混乱(引用[1][3]) **解决方案**: 1. 使用前置声明打破循环依赖 2. 将实现与声明分离 ```cpp // a.h(解决方案示例) namespace XXX { // 前置声明 struct MyStruct; } // b.h #include "a.h" namespace YYY { class MyClass { XXX::MyStruct* ptr; // 使用指针(不要求完整定义) }; } // a.cpp(完整定义) namespace XXX { struct MyStruct { int data; // 成员定义... }; } ``` --- #### 👁️ 原因 3:命名空间作用域错误 **问题**:未正确限定命名空间(引用[2][4]) **解决方案**: ```cpp // 错误用法 MyStruct s; // 未指定命名空间 // 正确用法 1:显式限定 XXX::MyStruct s1; // 正确用法 2:using 声明 using XXX::MyStruct; MyStruct s2; // 正确用法 3:using 指令(谨慎使用) using namespace XXX; MyStruct s3; ``` --- #### 📦 原因 4:类型定义不完整 **问题**:头文件中只有声明没有定义(引用[3]) **解决方案**: ```cpp // a.h(正确头文件示例) #ifndef A_HEADER #define A_HEADER namespace XXX { // 完整定义 struct MyStruct { int x; double y; void print(); // 声明 }; // 函数声明 void process(MyStruct&); } #endif // a.cpp(实现文件) #include "a.h" #include <iostream> namespace XXX { // 成员函数实现 void MyStruct::print() { std::cout << x << ", " << y; } // 函数实现 void process(MyStruct& s) { ... } } ``` --- #### ⚠️ 原因 5:在类作用域错误修改变量 **问题**:在类定义中直接执行操作而非声明(引用[4]) **解决方案**: 将操作移到构造函数或成员函数中 ```cpp // 错误示例 class BadExample { XXX::MyStruct s; s.x = 5; // 错误:类作用域内不能直接赋值 }; // 正确示例 class GoodExample { XXX::MyStruct s; public: GoodExample() { s.x = 5; // 在构造函数中初始化 } }; ``` --- ### 总结检查清单 1. ✅ 包含定义命名空间的头文件(`#include "a.h"`) 2. ✅ 使用完全限定名(`XXX::MyStruct`) 3. ✅ 确保头文件中有完整的类型定义 4.解决循环依赖(使用前置声明+指针/引用) 5. ✅ 避免在类定义中直接操作数据成员 遵循这些步骤可解决 95% 的 `does not name a type` 错误。若问题仍存在,检查编译器输出中具体的行号和错误上下文。
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