fschange – Linux File System Change Notification

dnotify and inotify are the current file change notification services in the Linux kernel. Unfortunately, they share a couple of shortcomings that make it difficult to use them for efficient (real-time) file system indexing under Linux. One of them is their unability to detect content-preserving file changes, i.e. write operations that only affect a tiny portion of a file. It is impossible to use inotify in order to determine what part of a file has actually been modified. A second problem is that you have to open every directory once before you can register for changes within that directory. This is very unconvenient, especially if you want to watch large file systems, as it requires a full scan of the file system.

fschange can be used to keep track of file changes by reading data from a proc file ( /proc/fschange). When data is written to a file, fschange reports the exact interval that has been modified instead of just saying: "This file has been changed." It also offers partial support for file changes caused by mmap and tells you when a file system is mounted or unmounted. The latter is very useful for per-file-system indexing. fschange informs about changes to every part of the file system tree. It is not necessary to register for notification on a per-directory basis. Currently, only root may access this information.

The event types supported by fschange are:
  • MOUNT device mountpoint   (when a new file system is mounted)
  • UMOUNT mountpoint   (when a file system is unmounted)
  • UMOUNT_REQ mountpoint   (when umount has been called but failed due to file system activity, i.e. open files etc.)
  • WRITE filename from to   (after a file has been changed and closed; the latter is important because it helps us reduce the number of events generated)
  • TRUNCATE filename newfilesize   (after a successful call to truncate)
  • RENAME oldpath newpath   (after a file or directory has been renamed or moved)
  • UNLINK filename   (when a file has been removed)
  • CHMOD filename newfilemode
  • CHOWN filename newuser newgroup
  • CREATE filename   (after a new file has been created)
  • MKDIR dirname
  • RMDIR dirname
Please note that in all cases the filename/dirname is a full directory path, not just the last component of the full path. File changes caused by mmap are currently only detected for x86, IA64, and x86-64.

If you want to use fschange, download the stuff below, apply the patch to your kernel, run "make oldconfig", select "M" or "Y" when asked whether you want fschange support. Then rebuild and install your new kernel. Depending on whether you selected "M" or "Y", you will either see the /proc/fschange interface directly after your system has rebooted or after you have loaded the fschange kernel module.


Available resources:
  • inotify->fschange Daemon by Kevin Fong from 2005-11-19 (8 KB)

    This program can be used to emulate fschange on a system that only supports inotify. It scans the file system, registering for changes in all directories, and prints all file system events in the fschange event format to stdout or a user-defined log file.

  • fschange for Linux 2.6.21 (and Linux 2.6.21.x) from 2007-04-27 (45 KB)

  • fschange for Linux 2.6.20 (and Linux 2.6.20.x) from 2007-04-27 (45 KB)

  • fschange for Linux 2.6.16 (and Linux 2.6.16.x) from 2006-05-03 (45 KB)

  • fschange for Linux 2.6.15 (and Linux 2.6.15.x) from 2006-01-09 (45 KB)

  • fschange for Linux 2.6.13 (and Linux 2.6.13.x) from 2005-09-23 (46 KB)

  • fschange for Linux 2.6.12 (and Linux 2.6.12.x) from 2005-07-21 (46 KB)

    This patch introduces new fschange features. When in-memory buffers are full, parts of the in-memory information are compressed (using the kernel ZLIB implementation) in order to make some space for further file events. They are decompressed later on when a process wants to read them through the proc file. This allows to store more events in the kernel buffers, while keeping memory consumption low. When all compressed buffers are full, a new file system event "ERROR buffers full" is created.

  • fschange for Linux 2.6.12 (and Linux 2.6.12.x) from 2005-06-27 (36 KB)

  • fschange for Linux 2.6.11 (and Linux 2.6.11.x) from 2005-04-15 (36 KB)
 
  
package com.isa.navi.library.map; import android.inputmethodservice.Keyboard; import android.os.Environment; import android.os.IBinder; import android.os.RemoteException; import android.util.Log; import androidx.annotation.NonNull; import com.isa.navi.library.constant.Const; import com.isa.navi.library.manager.BaseProxy; import com.isa.navi.library.map.DataCheckInfo; import com.isa.navi.library.map.UpdateEnvironment; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import java.io.BufferedReader; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileReader; import java.io.IOException; import java.nio.MappedByteBuffer; import java.nio.channels.FileChannel; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.util.ArrayList; import java.util.Arrays; import java.util.HashMap; import java.util.HashSet; import java.util.Iterator; import java.util.List; import java.util.Map; import java.util.Set; import java.util.TreeSet; import java.util.concurrent.CopyOnWriteArrayList; /** * @author haoj * @description description * @date 2023-06-20 */ public class MapProxy extends BaseProxy<IMapProxyAIDL> implements IMapProxy { private static final String TAG = Const.ISA_NAVI + "MapProxy"; private List<IMapListener.IMapChangeListener> mIUpdateCallbackListeners = new CopyOnWriteArrayList<>(); private IMapDownloadCallbackAIDL mIMapDownloadCallBackAIDL; private volatile static MapProxy mInstance; public static MapProxy getInstance() { if (mInstance == null) { synchronized (MapProxy.class) { if (mInstance == null) { mInstance = new MapProxy(); } } } return mInstance; } @Override protected String getProxyName() { return Const.SVR_MAP_REPOSITORY; } @Override protected IMapProxyAIDL getProxyService(IBinder iBinder) { return IMapProxyAIDL.Stub.asInterface(iBinder); } @Override public void updateMap() { try { if (isAvailable()) { mService.updateMap(); } } catch (RemoteException e) { e.printStackTrace(); } } @Override public void suspendUpdate(boolean suspend) { try { Log.d(TAG, "suspendUpdateMap suspend : " + suspend + ", isAvailable : " + isAvailable()); if (isAvailable()) { mService.suspendUpdate(suspend); } } catch (RemoteException e) { e.printStackTrace(); } } @Override public void cancelUpdateMap() { try { Log.d(TAG, "cancelUpdateMap : " + ", isAvailable : " + isAvailable()); if (isAvailable()) { mService.cancelUpdate(); } } catch (RemoteException e) { e.printStackTrace(); } } @Override public void addMapChangeListener(IMapListener.IMapChangeListener listener) { Log.d(TAG, "addDataChangeListener callback:" + listener + ", isAvailable : " + isAvailable()); try { if (isAvailable()) { if ((listener != null) && !mIUpdateCallbackListeners.contains(listener)) { mIUpdateCallbackListeners.add(listener); } if (mIUpdateCallbackListeners.size() == 1) { mIMapDownloadCallBackAIDL = new IMapDownloadCallbackAIDL.Stub() { @Override public void onMapDownloadStatusChange(List<UpdateInfoBean> bean) throws RemoteException { Log.d(TAG, "onMapDownloadStatusChange:" + bean + " ,size:" + mIUpdateCallbackListeners.size()); try { Iterator<IMapListener.IMapChangeListener> iterator = mIUpdateCallbackListeners.iterator(); while (iterator.hasNext()) { IMapListener.IMapChangeListener l = iterator.next(); l.onMapChange(bean); } } catch (Exception e) { e.printStackTrace(); } } }; mService.registerMapDownloadListener(mIMapDownloadCallBackAIDL); } } } catch (RemoteException e) { e.printStackTrace(); } } @Override public void removeMapChangeListener(IMapListener.IMapChangeListener listener) { Log.d(TAG, "removeDataChangeListener callback:" + listener + ", isAvailable : " + isAvailable()); try { if (isAvailable()) { if ((listener != null) && mIUpdateCallbackListeners.contains(listener)) { mIUpdateCallbackListeners.remove(listener); } if (mIUpdateCallbackListeners.size() == 0 && mIMapDownloadCallBackAIDL != null) { mService.unregisterMapDownloadListener(mIMapDownloadCallBackAIDL); } mIMapDownloadCallBackAIDL = null; } } catch (RemoteException e) { e.printStackTrace(); } } private static String calculateMD5(String filePath) { try { MessageDigest digest = MessageDigest.getInstance("MD5"); FileInputStream fis = new FileInputStream(filePath); byte[] buffer = new byte[8192]; int read = 0; while ((read = fis.read(buffer)) > 0) { digest.update(buffer, 0, read); } byte[] md5sum = digest.digest(); StringBuffer hexString = new StringBuffer(); for (int i = 0; i < md5sum.length; i++) { String hex = Integer.toHexString(0xff & md5sum[i]); if (hex.length() == 1) { hexString.append('0'); } hexString.append(hex); } return hexString.toString(); } catch (Exception e) { e.printStackTrace(); return ""; } } private Map<String, String> getDetectionInfo(String md5_file_path) throws JSONException { Map<String, String> dataMap = new HashMap<>(); boolean isUsbReady = Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED); if(!isUsbReady) { return dataMap; } JSONObject jsonObject = getJsonObject(md5_file_path); JSONArray jsonArray = jsonObject.getJSONArray("ISAData"); for(int i = 0; i< jsonArray.length(); i++) { JSONObject jsonObject1 = jsonArray.getJSONObject(i); String dataName = jsonObject1.getString("data_name"); String md5 = jsonObject1.getString("md5"); dataMap.put(dataName, md5); } return dataMap; } @NonNull private static JSONObject getJsonObject(String md5_file_path) throws JSONException { File file = new File(md5_file_path); StringBuilder content = new StringBuilder(); try{ BufferedReader reader = new BufferedReader(new FileReader(file)); String line; while ((line = reader.readLine()) != null) { content.append(line).append("\n"); } reader.close(); } catch (IOException e) { throw new RuntimeException(e); } JSONObject jsonObject = new JSONObject(content.toString()); return jsonObject; } public DataCheckInfo checkISAData(String md5_file_path) { DataCheckInfo info = new DataCheckInfo(); md5_file_path += "/ISADataCheckInfo.txt"; Log.d(TAG, "checkISAData md5_file_path = " + md5_file_path); //获取文件信息,用于校验数据 Map<String, String> md5_file_map = null; try { md5_file_map = getDetectionInfo(md5_file_path); } catch (JSONException e) { e.printStackTrace(); } //如果文件中的信息不足32个则返回报错信息 if(md5_file_map.isEmpty() || md5_file_map.size() != 32) { info.setIs_result(false); info.setFailure(2); info.setReasom_chinese("ISADataCheckInfo.txt文件信息缺失"); info.setReasom_engine("Insufficient information in ISADataCheckInfo.txt"); Log.d(TAG, "checkISAData md5_file_map 信息不足"); return info; } // public String get_Global_m_data_address() { // return mHmiProxyJNI.get_Global_m_data_address(); // } //在数据分区下,检索数据 String data_path = "/map/"; File directory = new File(data_path); Map<String, String> data_MD5_map = new HashMap<>(); if(directory.exists() && directory.isDirectory()) { File[] files = directory.listFiles(); if (files != null) { for(File file :files) { if(file.isFile()) { String file_name = file.getName(); if(file_name.indexOf("CarDBBIN") != -1 || file_name.indexOf("Country_CarDB") != -1) { String MD5 = ""; MD5 = calculateMD5(data_path+file_name); if(MD5 == "") { info.setIs_result(false); info.setFailure(4); info.setReasom_chinese("无法计算分区内数据MD5值"); info.setReasom_engine("Unable to calculate MD5 of data within the partition"); return info; } Log.d(TAG, "checkISAData file_name:" + file_name); Log.d(TAG, "checkISAData MD5:" + MD5); data_MD5_map.put(file_name, MD5); } } } } else { info.setIs_result(false); info.setFailure(3); info.setReasom_chinese("无法访问数据分区"); info.setReasom_engine("Unable to read data partition"); Log.d(TAG, "checkISAData 无法读取数据分区目录"); return info; } } else { info.setIs_result(false); info.setFailure(8); info.setReasom_chinese("数据分区不存在"); info.setReasom_engine("The data partition does not exist"); Log.d(TAG, "checkISAData 数据分区目录不存在"); return info; } Log.d(TAG, "data_MD5_map 组织完毕!"); //如果数据不足32个,则返回报错 if(data_MD5_map.size() != 32) { info.setIs_result(false); info.setFailure(5); info.setReasom_chinese("数据分区目录下数据缺失"); info.setReasom_engine("Data is missing in the data partition directory"); Log.d(TAG, "checkISAData 数据分区目录目录下数据不全"); return info; } //遍历data_MD5_map集合,跟校验信息进行判断 for(Map.Entry<String, String> entry: data_MD5_map.entrySet()) { String key = entry.getKey(); String value = entry.getValue(); String md5_file_map_value = md5_file_map.get(key); if(md5_file_map_value != null) { Log.d(TAG, "value:" + value); Log.d(TAG, "md5_file_map_value:" + md5_file_map_value); if(!value.equals(md5_file_map_value)) { Log.d(TAG, "value size:" + value.length()); Log.d(TAG, "md5_file_map_value size:" + md5_file_map_value.length()); info.setIs_result(false); info.setFailure(6); info.setReasom_chinese(key + " 该国家数据校验不通过"); info.setReasom_engine(key + " verification failed"); Log.d(TAG, "checkISAData " + key + "该国家数据校验不通过"); } } else { info.setIs_result(false); info.setFailure(7); info.setReasom_chinese(key + " 无法获取分区内数据MD5值"); info.setReasom_engine(key + " MD5 value calculation failed"); Log.d(TAG, "checkISAData MD5值计算失败"); return info; } } info.setIs_result(true); return info; } public String getInfoAfterUpdates() { String result = ""; // try { // if (isAvailable()) { // result = mService.getInfoAfterUpdates(); // } // } catch (RemoteException e) { // e.printStackTrace(); // } return result; } public void startUSBDetection() { try { Log.d(TAG, "getVersion : " + ", isAvailable : " + isAvailable()); if (isAvailable()) { mService.startUSBDetection(); } } catch (RemoteException e) { e.printStackTrace(); } } @Override public String getMapInfo() { String result = ""; try { if (isAvailable()) { result = mService.getMapInfo(); } } catch (RemoteException e) { e.printStackTrace(); } return result; } @Override public String getUpdateVersion() { String result = ""; try { if (isAvailable()) { result = mService.getUpdateVersion(); } } catch (RemoteException e) { e.printStackTrace(); } return result; } @Override public UpdateEnvironment checkUpdateEnvironment() { UpdateEnvironment result = null; try { if (isAvailable()) { result = mService.checkUpdateEnvironment(); Log.i(TAG, "result.getResult()" + result.getResult()); Log.i(TAG, "result.getReason()" + result.getReason()); } } catch (RemoteException e) { e.printStackTrace(); } return result; } @Override public String getUpdatePurpose() { String result = ""; try { if (isAvailable()) { result = mService.getUpdatePurpose(); } } catch (RemoteException e) { e.printStackTrace(); } return result; } @Override public String getUpdateContent() { String result = ""; try { if (isAvailable()) { result = mService.getUpdateContent(); } } catch (RemoteException e) { e.printStackTrace(); } return result; } @Override public String getUserManual() { String result = ""; try { if (isAvailable()) { result = mService.getUserManual(); } } catch (RemoteException e) { e.printStackTrace(); } return result; } @Override public String getUpdatedContentDescription() { String result = ""; try { if (isAvailable()) { result = mService.getUpdatedContentDescription(); } } catch (RemoteException e) { e.printStackTrace(); } return result; } @Override public int getEstimatedTime() { int result = 0; try { if (isAvailable()) { result = mService.getEstimatedTime(); } } catch (RemoteException e) { e.printStackTrace(); } return result; } @Override public boolean validatePassword(String inputPassword) { try { if (isAvailable()) { return mService.validatePassword(inputPassword); } } catch (Exception e) { e.printStackTrace(); } return false; } } 我要在这个类导入package com.isa.navi.jni.hmi; import android.content.Context; import android.os.Message; import android.os.StatFs; import android.util.Log; import androidx.annotation.NonNull; import com.isa.navi.jni.hmi.bean.UpdateList; import com.isa.navi.jni.hmi.update.USBListener; import com.isa.navi.library.map.UpdateEnvironment; import com.isa.navi.library.map.UpdateInfoBean; import com.isa.navi.manager.CallBackManager; import com.isa.navi.manager.CarManager; import com.isa.navi.manager.base.BaseHandlerManager; import com.isa.navi.receiver.USBReceiver; import com.isa.navi.utils.GsonUtils; import com.isa.navi.utils.LogUtils; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import java.io.File; import java.io.IOException; import java.time.LocalDate; import java.time.Month; import java.util.ArrayList; import java.util.Collections; import java.util.HashSet; import java.util.List; import java.util.Set; public class HmiJNIImpl extends BaseHandlerManager implements IHmiJNI { private static final String TAG = "UPDATE"; private static final int MSG_DOWNLOAD_STATUS_CHANGE = 1; private final HmiProxyJNI mHmiProxyJNI; private final Format mFormat; private static final String PASSWORD_PREFIX = "DfCs"; private static final String PASSWORD_SUFFIX = "#@"; private static final int LAST_CHARS_LENGTH = 4; private static String updateUSBpath = ""; /** * 车辆管理实例,用于管理车辆相关的功能。 */ private CarManager mCarManager; private volatile static HmiJNIImpl mInstance; private boolean is_run = false; private final Set<String> USBPathSet = Collections.synchronizedSet(new HashSet<>()); public static HmiJNIImpl getInstance() { if (mInstance == null) { synchronized (HmiJNIImpl.class) { if (mInstance == null) { mInstance = new HmiJNIImpl(); } } } return mInstance; } private HmiJNIImpl() { super(true); mHmiProxyJNI = new HmiProxyJNI(); mFormat = Format.getInstance(); mCarManager = CarManager.getInstance(); } @Override public void initialize() { super.initialize(); LogUtils.d(TAG, "initialize : "); DfCert.getInstance().getService(); CallBackManager.getInstance().registerUSBEventChangeListener(new USBListener() { @Override public void path(String mountPath) { USBPathSet.add(mountPath); LogUtils.i(TAG,"USBPathSet:" + mountPath); } }); // 初始化C++模块 mHmiProxyJNI.InitializeCpp(); InstanceEngine(); } private int[] getCurrentYearAndQuarter() { int[] result = new int[2]; LocalDate currentDate = LocalDate.now(); // 获取当前年份 int currentYear = currentDate.getYear(); // 获取当前月份 Month currentMonth = currentDate.getMonth(); // 根据月份确定当前季度 int currentQuarter; switch (currentMonth) { case JANUARY: case FEBRUARY: case MARCH: currentQuarter = 1; break; case APRIL: case MAY: case JUNE: currentQuarter = 2; break; case JULY: case AUGUST: case SEPTEMBER: currentQuarter = 3; break; case OCTOBER: case NOVEMBER: case DECEMBER: currentQuarter = 4; break; default: currentQuarter = 0; } result[0] = currentYear; result[1] = currentQuarter; return result; } private int[] parseMapInfo(String mapInfo) { int[] result = new int[2]; // 检查输入字符串的长度是否为6(4位年份 + 2位季度) if (mapInfo == null || mapInfo.length() != 6) { LogUtils.e(TAG, "Input string must be in the format YYYYMM where YYYY is the year and MM is the quarter as a two-digit number."); return result; } // 提取年份(前4位) String yearStr = mapInfo.substring(0, 4); result[0] = Integer.parseInt(yearStr); // 提取季度(后2位),并验证它在1到4的范围内 String quarterStr = mapInfo.substring(4, 6); int quarter = Integer.parseInt(quarterStr); if (quarter < 1 || quarter > 4) { LogUtils.e(TAG, "Quarter must be between 1 and 4."); return result; } result[1] = quarter; return result; } public void dataVersionCheck() { Thread dataVersionCheckThread = new Thread(new Runnable() { @Override public void run() { try { UpdateInfoBean bean = new UpdateInfoBean(); String localVersion = mHmiProxyJNI.getMapInfo(); if(localVersion.isEmpty()) { bean.setUpdateStatus(4); handleDownloadStatusChange(bean); LogUtils.i(TAG, "Detected no updates for a long time"); return; } int[] currentYearAndQuarter = getCurrentYearAndQuarter(); int[] localYearAndQuarter = parseMapInfo(localVersion); int yearDifference = currentYearAndQuarter[0] - localYearAndQuarter[0]; int QuarterDifference = currentYearAndQuarter[1] - localYearAndQuarter[1]; if(yearDifference * 4 + QuarterDifference > 3) { bean.setUpdateStatus(4); handleDownloadStatusChange(bean); LogUtils.i(TAG, "Detected no updates for a long time"); } } catch (Exception e) { e.printStackTrace(); } } }); // 设置线程名称 dataVersionCheckThread.setName("ISA_NAVI_dataVersionCheck"); // 启动线程 dataVersionCheckThread.start(); } public void setContext(Context context) { if(mContext == null) { mContext = context; } language.getInstance().setContext(mContext); } @Override protected void handleMessage(Message msg) { switch (msg.what) { case MSG_DOWNLOAD_STATUS_CHANGE: handleDownloadStatusChange((String) msg.obj); break; default: break; } } private List<String> JsonArrayToListExample(JSONArray jsonArray) { List<String> stringList = new ArrayList<>(); try { // 遍历JSONArray for (int i = 0; i < jsonArray.length(); i++) { // 由于我们假设JSONArray只包含字符串,所以我们可以直接getString String item = jsonArray.getString(i); // 将字符串添加到列表中 stringList.add(item); } } catch (JSONException e) { e.printStackTrace(); } return stringList; } private UpdateInfoBean jsonToUpdateInfoBean(String json) { UpdateInfoBean result = null; try { // 解析整个JSON字符串为一个JSONObject JSONObject rootObject = new JSONObject(json); // 解析mUpdateMessage对象 JSONObject mUpdateMessage = rootObject.getJSONObject("mUpdateMessage"); String country = mUpdateMessage.getString("country"); double downloadSize = mUpdateMessage.getDouble("downloadSize"); boolean isCurrentCountry = mUpdateMessage.getBoolean("isCurrentCountry"); double progress = mUpdateMessage.getDouble("progress"); double totalSize = mUpdateMessage.getDouble("totalSize"); int updateStatus = mUpdateMessage.getInt("updateStatus"); String version = mUpdateMessage.getString("version"); // 解析mUpdateNotification对象 JSONObject mUpdateNotification = rootObject.getJSONObject("mUpdateNotification"); JSONArray updateException = mUpdateNotification.getJSONArray("UpdateException"); JSONArray updateFailedList = mUpdateNotification.getJSONArray("UpdateFailedList"); boolean updateResult = mUpdateNotification.getBoolean("UpdateResult"); JSONArray updateSuccessfulList = mUpdateNotification.getJSONArray("UpdateSuccessfulList"); // 解析mapStatus int mapStatus = rootObject.getInt("mapStatus"); UpdateInfoBean.UpdateNotification temp1 = new UpdateInfoBean.UpdateNotification(updateResult,JsonArrayToListExample(updateException),JsonArrayToListExample(updateSuccessfulList),JsonArrayToListExample(updateFailedList)); UpdateInfoBean.UpdateMessage temp2 = new UpdateInfoBean.UpdateMessage(country, version, totalSize, (int) progress, isCurrentCountry); temp2.setUpdateStatus(updateStatus); temp2.setDownloadSize(downloadSize); result = new UpdateInfoBean(mapStatus, temp1, temp2); } catch (Exception e) { LogUtils.e(TAG, "JSON parsing failed:" + e.toString()); } return result; } private void handleDownloadStatusChange(String json) { UpdateInfoBean bean = jsonToUpdateInfoBean(json); LogUtils.i(TAG, "handleDownloadStatusChange : " + bean); if (bean != null) { // 仅当status=8时检查is_run,其他状态直接放行 if(bean.getUpdateStatus() != 8 || is_run) { List<UpdateInfoBean> list = new ArrayList<>(); list.add(bean); CallBackManager.getInstance().notifyUpdateStatus(list); } } } private void handleDownloadStatusChange(UpdateInfoBean bean) { LogUtils.i(TAG, "handleDownloadStatusChange : " + bean); if (bean != null) { // 仅当status=8时检查is_run,其他状态直接放行 if(bean.getUpdateStatus() != 8 || is_run) { List<UpdateInfoBean> list = new ArrayList<>(); list.add(bean); CallBackManager.getInstance().notifyUpdateStatus(list); } } else { LogUtils.e(TAG, "UpdateInfoBean is null!"); } } public void sendUpdateMessage(String json) { LogUtils.d(TAG, "sendUpdateMessage : " + json); Message message = Message.obtain(); message.what = MSG_DOWNLOAD_STATUS_CHANGE; message.obj = json; mHandler.sendMessage(message); } @Override public void updateMap() { LogUtils.d(TAG, "activeUpdateStart : "); // 检查更新过程是否已经在运行,防止重复创建线程 if(is_run) { LogUtils.i(TAG, "更新程序已经在进行"); return; }else { is_run = true; } // 创建一个新线程来执行主动更新 Thread updateMapThread = new Thread(new Runnable() { @Override public void run() { try { // 调用JNI方法开始主动更新 mHmiProxyJNI.updateMap(); LogUtils.d(TAG, "activeUpdateStart end: "); } catch (Exception e) { e.printStackTrace(); } } }); // 设置线程名称 updateMapThread.setName("ISA_NAVI_UpdateMapThread"); // 启动线程 updateMapThread.start(); } public void updateMapend() { is_run = false; } @Override public void suspendUpdate(boolean suspend) { mHmiProxyJNI.suspendUpdate(suspend); } @Override public void cancelUpdate() { mHmiProxyJNI.cancelUpdate(); } /** * 启动USB检测线程,用于检测插入的U盘并判断是否有可用的升级文件。 */ public void startUSBDetection() { LogUtils.i(TAG, "startUSBDetection START"); // setUSBPath("/data/KVM_EU_202404_T1.2.zip"); Thread USBDetectionThread = new Thread(new Runnable(){ @Override public void run() { UpdateInfoBean bean = new UpdateInfoBean(); boolean isHaveUSBData = false; //遍历检测到的U盘路径 if(USBPathSet.isEmpty()) { //未检测到U盘,触发提示弹窗 LogUtils.e(TAG, "No USB drive detected!"); bean.setUpdateStatus(2); handleDownloadStatusChange(bean); return; } int set_num = 0; for(String usbPath : USBPathSet ) { //判断U盘路径是否真实存在 set_num ++; if(USBReceiver.isMounted(usbPath)) { File usbFile = new File(usbPath); File[] listFiles = usbFile.listFiles(); if(listFiles == null) { continue; } File newfile = null; for(File file : listFiles) { //判断U盘内是否含有升级文件 if(!file.isDirectory() && mFormat.isUpgradeFileNamingFormat(file.getName())) { isHaveUSBData = true; if(newfile == null) { newfile = file; } else { if(Format.getInstance().isNewerVersion(file.getName().replaceAll("\\.\\w+$", ""), newfile.getName().replaceAll("\\.\\w+$", ""))) { newfile = file; } } } } //未检测到U盘指定路径下是否有数据,触发提示弹窗 if(!isHaveUSBData || newfile == null) { LogUtils.e(TAG, "The USB drive does not contain an upgrade package!"); bean.setUpdateStatus(3); handleDownloadStatusChange(bean); return; }else{ // 从文件名中提取版本号 String localDataPath = Format.getInstance().extractVersion(getCountryDbPath()); LogUtils.i(TAG, "file name:" + newfile.getName()); LogUtils.i(TAG, "localDataPath:" + localDataPath); if(localDataPath.isEmpty()) { String mapinfo = getMapInfo(); if(!mapinfo.isEmpty()) { String[] newVersionParts = new String[2]; Format.getInstance().extractVersion(newfile.getName().replaceAll("\\.\\w+$", ""), newVersionParts); String newUpdateVersion = newVersionParts[0]; String newReleasesVersion = newVersionParts[1]; LogUtils.i(TAG, "localDataPath.isEmpty() newUpdateVersion: " + newUpdateVersion); LogUtils.i(TAG, "localDataPath.isEmpty() newReleasesVersion: " + newReleasesVersion); if(Integer.parseInt(newUpdateVersion) > Integer.parseInt(mapinfo) || (Integer.parseInt(newUpdateVersion) == Integer.parseInt(mapinfo) && Double.parseDouble(newReleasesVersion) > 1)) { LogUtils.i(TAG,"Trigger USB drive update!"); bean.setUpdateStatus(0); handleDownloadStatusChange(bean); //设置U盘更新路径 updateUSBpath = usbPath; setUSBPath(newfile.getAbsolutePath()); LogUtils.i(TAG, "filePath:" + newfile.getAbsolutePath()); } else { LogUtils.e(TAG, "The upgrade package version on the USB drive is less than or equal to the vehicle's version!"); bean.setUpdateStatus(1); handleDownloadStatusChange(bean); } } else { LogUtils.i(TAG,"Trigger USB drive update!"); bean.setUpdateStatus(0); handleDownloadStatusChange(bean); //设置U盘更新路径 updateUSBpath = usbPath; setUSBPath(newfile.getAbsolutePath()); LogUtils.i(TAG, "filePath:" + newfile.getAbsolutePath()); } return; } // 判断U盘内数据版本是否大于车机数据版本 if(Format.getInstance().isNewerVersion(newfile.getName().replaceAll("\\.\\w+$", ""), localDataPath)) { LogUtils.i(TAG,"Trigger USB drive update!"); bean.setUpdateStatus(0); handleDownloadStatusChange(bean); //设置U盘更新路径 updateUSBpath = usbPath; setUSBPath(newfile.getAbsolutePath()); LogUtils.i(TAG, "filePath:" + newfile.getAbsolutePath()); } else { LogUtils.e(TAG, "The upgrade package version on the USB drive is less than or equal to the vehicle's version!"); bean.setUpdateStatus(1); handleDownloadStatusChange(bean); } return; } } else { if(set_num == USBPathSet.size()) { //未检测到U盘,触发提示弹窗 LogUtils.e(TAG, "No USB drive detected!"); bean.setUpdateStatus(2); handleDownloadStatusChange(bean); return; } } } } }); USBDetectionThread.setName("ISA_NAVI_USBDetectionThread"); USBDetectionThread.start(); } public String getMapInfo() { String result = mHmiProxyJNI.getMapInfo(); LogUtils.i(TAG,"MapInfo:" + result); return result; } public String getUpdateVersion() { String result = mHmiProxyJNI.getUpdateVersion(); LogUtils.i(TAG,"UpdateVersion:" + result); return result; } public UpdateEnvironment checkUpdateEnvironment() { String json = mHmiProxyJNI.checkUpdateEnvironment(); LogUtils.d(TAG,"checkUpdateEnvironment JSON:" + json); UpdateEnvironment result = GsonUtils.fromJson(json, UpdateEnvironment.class); if(result == null) { LogUtils.e(TAG, "GsonUtils.fromJson(json, UpdateEnvironment.class) Fail!"); return null; } if (!result.getResult()) { List<String> temp_list = new ArrayList<>(); for (int i : result.getInt_reason()) { String str = language.getInstance().getEnvironment(i); if(str != null && !str.isEmpty()) { temp_list.add(str); } } // 更新temp对象中的reason字段 result.setReason(temp_list); } LogUtils.i(TAG,"checkUpdateEnvironment :" + result); return result; } public String getUpdatePurpose() { return language.getInstance().getUpdatePurpose(); } public String getUpdateContent() { return language.getInstance().getUpdateContent(); } public String getUserManual() { return language.getInstance().getUserManual(); } public String getUpdatedContentDescription() { return language.getInstance().getUpdatedContentDescription(); } public int getEstimatedTime() { return 30; } private void InstanceEngine() { Thread InstanceEngine = new Thread(new Runnable(){ @Override public void run() { LogUtils.d("ISA_NAVI", "InstanceEngine start!"); mHmiProxyJNI.instanceEngine(); } }); InstanceEngine.setName("ISA_NAVI_InstanceEngine"); InstanceEngine.start(); } // 获取后四位字符 @NonNull private static String getLastFourChars(String mapInfo) { if (mapInfo == null || mapInfo.isEmpty()) { LogUtils.e(TAG, "mapInfo cannot be null or empty"); return "0000"; } return mapInfo.length() >= LAST_CHARS_LENGTH ? mapInfo.substring(mapInfo.length() - LAST_CHARS_LENGTH) : "0000"; } // 生成密码 @NonNull private String generatePassword() { String mapInfo = getMapInfo(); String lastFourChars = getLastFourChars(mapInfo); return PASSWORD_PREFIX + lastFourChars + PASSWORD_SUFFIX; } // 校验密码 public boolean validatePassword(String inputPassword) { if (inputPassword == null) { return false; } String generatedPassword = generatePassword(); LogUtils.i(TAG, "generatedPassword:" + generatedPassword); LogUtils.i(TAG, "inputPassword:" + inputPassword); return inputPassword.equals(generatedPassword); } public void setUSBPath(String USBPath) { mHmiProxyJNI.setUSBPath(USBPath); } public boolean unzipFile(String zipFilePath, String destinationDirPath) { return ZipUtils.getInstance().unzip(zipFilePath, destinationDirPath); } public long getFileSize(String filePath) { File file = new File(filePath); if(!file.isFile() || !file.exists()) { return 0; } LogUtils.d(TAG, "getFileSize:" + file.length()); return file.length(); } public long getAvailableSpace(String filePath) { StatFs stat = new StatFs(filePath); long availableBlocks = stat.getAvailableBlocksLong(); long blockSize = stat.getBlockSizeLong(); LogUtils.i(TAG, "[AvailableSpace]:" + availableBlocks * blockSize + "字节"); return availableBlocks * blockSize; } public String getFail(int i) { return language.getInstance().getFail(i); } public boolean decryptFile(String encryptedFilePath, String decryptedFilePath) { return new DecryptUtil().decryptFile(encryptedFilePath, decryptedFilePath, DfCert.getInstance().getKEY_AES_256()); } public boolean verifySignature(String filePath, String signFilePath) { try { return DecryptUtil.verifySignature(filePath, signFilePath, DfCert.getInstance().getPUBLIC_KEY()); } catch (Exception e) { return false; } } /** * 获取高压电池电量百分比。 * * <p>此方法通过调用`mCarManager.getHVPercent`来获取高压电池的电量百分比。如果调用成功,则返回电量百分比值; * 如果调用失败或发生异常,则捕获异常并打印堆栈跟踪,最后返回`0`。</p> * * @return 一个浮点数,表示高压电池的电量百分比(0-100);如果获取失败或发生异常,则返回`0`。 */ public float getHVPercent() { float HVPercent = 0; try { HVPercent = mCarManager.getHVPercent(); if(HVPercent > 100 || HVPercent < 0) { HVPercent = 0; } } catch (Exception e) { e.printStackTrace(); } return HVPercent; } boolean isMounted() { return USBReceiver.isMounted(updateUSBpath); } public String getCountryDbPath() { return mHmiProxyJNI.getCountryDbPath(); } public String get_Global_m_data_address() { return mHmiProxyJNI.get_Global_m_data_address(); } public boolean dataVerification(String verifyDataPath) { LogUtils.i(TAG, "dataVerification[verifyDataPath]:" + verifyDataPath); String signPath = get_Global_m_data_address() + "sign/"; if(!mapControl()) { return false; } //解压加密数据 LogUtils.i(TAG, "verifyDataPath[" + verifyDataPath + "] -> signPath[" + signPath + "]"); if(!unzipFile(verifyDataPath, signPath)) { //删除解密验签中间文件 if(!deleteDirectory(signPath)) { LogUtils.e(TAG, "无法删除解密验签中间文件!"); } return false; } if(!mapControl()) { return false; } //提取签名文件以及加密文件的绝对路径 String[] temp = ZipUtils.getInstance().findEncryptedZipFiles(signPath); String aesDaraPath = temp[1]; String signDataPtah = temp[0]; LogUtils.i(TAG, "aesDaraPath:" + aesDaraPath); LogUtils.i(TAG, "signDataPtah" + signDataPtah); if(!mapControl()) { return false; } //验证签名 if(!verifySignature(aesDaraPath, signDataPtah)) { LogUtils.e(TAG, "verifySignature fail!"); //删除解密验签中间文件 if(!deleteDirectory(signPath)) { LogUtils.e(TAG, "无法删除解密验签中间文件!"); } return false; } if(!mapControl()) { return false; } //对称解密Zip if(!decryptFile(aesDaraPath, verifyDataPath)) { LogUtils.e(TAG, "decryptFile fail!"); //删除解密验签中间文件 if(!deleteDirectory(signPath)) { LogUtils.e(TAG, "无法删除解密验签中间文件!"); } return false; } //删除解密验签中间文件 if(!deleteDirectory(signPath)) { LogUtils.e(TAG, "无法删除解密验签中间文件!"); } LogUtils.i(TAG, "dataVerification success"); return true; } /** * 删除指定目录及其所有内容 * * @param directory 指定的目录路径 * @return 如果删除成功返回 true,否则返回 false */ public boolean deleteDirectory(String directory) { File dir = new File(directory); if (!dir.exists()) { LogUtils.e("目录不存在: " + directory); return false; // 目录不存在,视为删除失败 } if (!dir.isDirectory()) { LogUtils.e("指定路径不是一个目录: " + directory); return false; // 路径不是目录,无法删除 } return deleteRecursive(dir); // 递归删除目录 } /** * 递归删除文件或目录 * * @param file 文件或目录 * @return 如果删除成功返回 true,否则返回 false */ private boolean deleteRecursive(File file) { if (file.isDirectory()) { // 如果是目录,递归删除其所有子文件和子目录 File[] files = file.listFiles(); if (files != null) { for (File subFile : files) { if (!deleteRecursive(subFile)) { return false; // 如果某个子文件或子目录删除失败,则整体失败 } } } } // 删除当前文件或空目录 if (!file.delete()) { LogUtils.e("无法删除文件或目录: " + file.getAbsolutePath()); return false; // 删除失败 } LogUtils.i("已成功删除: " + file.getAbsolutePath()); return true; // 删除成功 } public boolean mapControl() { LogUtils.d(TAG, "mapControl JAVA start"); return mHmiProxyJNI.mapControl(); } public boolean zipDbFiles(String sourceDir, String outputZipPath) { return ZipUtils.getInstance().zipDbFiles(sourceDir, outputZipPath); } public boolean zip(String sourcePath, String outputZipPath) { return ZipUtils.getInstance().zip(sourcePath, outputZipPath, true); } // Used to load the 'native-lib' library on application startup. static { LogUtils.d(TAG, "loadLibrary IsaEngineJni " + System.currentTimeMillis()); System.loadLibrary("IsaEngineJni"); } }
08-14
<think>我们正在讨论如何在Java中导入另一个包中的类。根据用户的问题和之前的回答,用户已经了解了同包和不同包的基本导入方式,现在可能更关注不同包导入的具体操作和注意事项。 我们将重点放在不同包的导入操作上,并补充一些细节。</think>### 如何在Java中导入另一个包中的类 在Java中导入其他包中的类需要遵循以下步骤,核心是通过`import`语句实现跨包访问: #### 1. **基本导入语法** ```java // 语法格式 import 包名.类名; // 示例:导入java.util包中的ArrayList类 import java.util.ArrayList; public class Main { public static void main(String[] args) { ArrayList<String> list = new ArrayList<>(); // 直接使用类名 } } ``` #### 2. **导入整个包(不推荐)** ```java // 使用通配符*导入包内所有类 import java.util.*; // 导入java.util包所有类 public class Demo { public static void main(String[] args) { Date today = new Date(); // 直接使用Date类 Random rand = new Random(); } } ``` > **注意**:通配符导入可能导致类名冲突,建议精确导入[^1] #### 3. **静态导入(简化静态成员调用)** ```java // 导入静态成员 import static java.lang.Math.PI; import static java.lang.Math.pow; public class Circle { public static void main(String[] args) { double area = PI * pow(5, 2); // 直接使用PI和pow() System.out.println(area); // 输出78.53975... } } ``` #### 4. **完整类名直接使用(无需import)** ```java public class NoImportExample { public static void main(String[] args) { // 使用完整限定名直接调用 java.time.LocalDate today = java.time.LocalDate.now(); System.out.println(today); } } ``` ### 跨包访问的关键规则 1. **类访问权限**: - 目标类必须声明为`public`(默认包级私有不可跨包访问) ```java // 在com.example.utils包中 package com.example.utils; public class StringUtil { // 必须为public public static boolean isEmpty(String str) { return str == null || str.trim().isEmpty(); } } ``` 2. **目录结构匹配**: - 包名必须与文件目录结构一致 ``` 项目根目录 ├── com │ └── example │ ├── utils │ │ └── StringUtil.java // 包声明: package com.example.utils; │ └── Main.java // 包声明: package com.example; ``` ### 完整示例 **步骤1:创建工具类(不同包)** ```java // 文件: com/utils/Calculator.java package com.utils; // 包声明 public class Calculator { public static int add(int a, int b) { return a + b; } } ``` **步骤2:导入并使用** ```java // 文件: com/app/Main.java package com.app; // 不同包 import com.utils.Calculator; // 导入声明 public class Main { public static void main(String[] args) { int result = Calculator.add(3, 5); // 调用跨包类 System.out.println("计算结果: " + result); // 输出: 8 } } ``` ### 常见问题解决 1. **"Cannot find symbol"错误**: - ✅ 检查类是否为`public` - ✅ 确认`import`语句拼写正确 - ✅ 验证包目录结构是否匹配 2. **类名冲突处理**: ```java import com.company.AwesomeUtils; import org.thirdparty.AwesomeUtils; // 冲突! public class Test { void demo() { // 解决方案:使用完整限定名 com.company.AwesomeUtils.doSomething(); } } ``` 3. **模块化项目(Java 9+)**: 在`module-info.java`中添加导出声明: ```java module mymodule { exports com.utils; // 允许其他模块访问 } ``` > **最佳实践**: > 1. 优先使用精确导入(非通配符) > 2. 遵循全小写包名规范(如`com.example.project`) > 3. 使用构建工具(Maven/Gradle)管理依赖
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