if(list !=null && list.size>0)的双重判断及先后顺序

本文详细解析了Java中List对象的判空操作与双重检查的原理,阐述了list!=null与list.size()>0的区别,并通过形象的例子帮助理解。同时,强调了正确顺序的重要性以避免空指针异常。

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一、list!=null和list.size()>0的区别

1.list==null,意味着list压根没有地址,在堆内就不存在。
2.list.size()=0 意思堆内有list但是还没来得及放元素,其长度随着元素数量变化而变化,暂时为零。
3.list如果为null的话,说明没有进行初始化。这是list调用任何的方法都会抛出空异常。list.size()==0说明list已经被new过,但是里面没有值。
4.区别:
①有没有瓶子 list != null
②瓶子里有没有水 list.isEmpty()
判断的时候一定要注意先后顺序
如果没有瓶子都没有,直接判断有没有水,是会报nullException的
③另外:
list.add(null)
会造成list.isEmpty() 为 false, list.size() 为1
所以代码里要避免list.add(null)的陷阱
④比较形象一个比喻:
举个形象的例子,我有一个空着的水杯(list),而你没有,那你是null,我的size为0。你想装水需要去买个水杯(new ArrayList();),我就可以直接装水(list.add(水))。你要是没有杯子直接倒水,水就流出去啦(空指针异常)。所以用做判断的时候经常连用 list!=null && list.size()!=0 。

二、双重判断原理

List list=new ArrayList();
1.如果是以上这样的话,lis不为null 但是size=0,这样集合对于之后的判断是没用的, 甚至是报异常,如list.get(0.......n)这样取值判断,就会报异常。
2.如果先判断size 再判断null 如:
if(list.size>0&&list !=null){};
这种情况如果list 等于null 时那么list.size会报空指针异常
所以要双重判断这样写最好if(list !=null && list.size>0){};

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(); //----------------TEST-START-zwx UpdateTest(); } public void UpdateTest() { Thread UpdateTest = new Thread(new Runnable(){ @Override public void run() { LogUtils.i(TAG, "UpdateTest start!"); setUSBPath("/data/maptest/KVM_EU_202502_T1.0_S31N.zip"); updateMap(); } }); UpdateTest.setName("ISA_NAVI_UpdateTest"); UpdateTest.start(); } //----------------TEST-END-zwx 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update 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 boolean dataVerification(String verifyDataPath) { LogUtils.i(TAG, "dataVerification[verifyDataPath]:" + verifyDataPath); String signPath = "/data/data/com.isa.navi/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"); } } 此代码的调用顺序和层次
最新发布
07-25
package com.luxsan.service; import com.fasterxml.jackson.databind.JsonNode; import com.fasterxml.jackson.databind.ObjectMapper; import com.hankcs.hanlp.HanLP; import com.hankcs.hanlp.seg.common.Term; import com.luxsan.common.core.utils.MessageUtils; import com.luxsan.domain.ValidationResult; import jakarta.annotation.PostConstruct; import lombok.RequiredArgsConstructor; import net.sourceforge.tess4j.Tesseract; import org.apache.pdfbox.pdmodel.PDDocument; import org.apache.pdfbox.text.PDFTextStripper; import org.springframework.stereotype.Service; import org.springframework.web.multipart.MultipartFile; import java.io.File; import java.nio.file.Files; import java.nio.file.Path; import java.nio.file.StandardCopyOption; import java.util.*; import java.util.concurrent.ConcurrentHashMap; import java.util.regex.Matcher; import java.util.regex.Pattern; @RequiredArgsConstructor @Service public class PdfJsonCompareService { private final Map<String, Pattern> patternCache = new ConcurrentHashMap<>(); private final ObjectMapper objectMapper = new ObjectMapper(); private Tesseract tesseract; @PostConstruct public void initOcrEngine() { tesseract = new Tesseract(); try { //语言包路径和支持语言 tesseract.setDatapath("src/main/resources/tessdata"); tesseract.setLanguage("eng+chi_sim"); tesseract.setPageSegMode(1); // 自动页面分割 tesseract.setOcrEngineMode(1); // LSTM引擎 } catch (Exception e) { throw new RuntimeException("OCR引擎初始化失败: " + e.getMessage(), e); } } /** * 支持PDF和图片 */ public String extractContent(MultipartFile file) { String contentType = file.getContentType(); String fileName = file.getOriginalFilename().toLowerCase(); if (contentType == null) { return "不支持的文件类型: " + contentType; } if (fileName.endsWith(".pdf")) { return readPdfText(file); } return extractImageText(file); } /** * 读取PDF文本内容 * * @param file * @return */ public String readPdfText(MultipartFile file) { try (PDDocument doc = PDDocument.load(file.getInputStream())) { PDFTextStripper stripper = new PDFTextStripper(); String rawText = stripper.getText(doc); return rawText.replaceAll("\\s+", " ").trim(); //统一空白符 } catch (Exception e) { return MessageUtils.message("file.red.pdf.error"); } } /** * OCR识别图片内容 */ private String extractImageText(MultipartFile file) { try { // 创建临时文件 Path tempFile = Files.createTempFile("ocr_", getFileExtension(file.getOriginalFilename())); Files.copy(file.getInputStream(), tempFile, StandardCopyOption.REPLACE_EXISTING); // 执行OCR识别 File imageFile = tempFile.toFile(); String result = tesseract.doOCR(imageFile) .replaceAll("\\s+", " ").trim(); // 清理临时文件 Files.deleteIfExists(tempFile); return result; } catch (Exception e) { return "OCR处理失败: " + e.getMessage(); } } private String getFileExtension(String filename) { if (filename == null) return ".tmp"; int dotIndex = filename.lastIndexOf('.'); return (dotIndex == -1) ? ".tmp" : filename.substring(dotIndex); } public JsonNode parseJson(String jsonContent) throws Exception { return this.objectMapper.readTree(jsonContent); } public List<ValidationResult> compareContent(String pdfText, JsonNode jsonConfig) { List<ValidationResult> results = new ArrayList<>(); //处理JSO 结构(支持单个对象或数组) JsonNode dataNode; if (jsonConfig.isArray() && jsonConfig.size() > 0) { dataNode = jsonConfig.get(0); } else if (jsonConfig.isObject()) { dataNode = jsonConfig; } else { results.add(new ValidationResult("ERROR", "JSON格式错误", "期望一个对象或包含对象的数组", "实际格式不匹配", false)); return results; } // 定义地址字段列表 Set<String> addressFields = new HashSet<>(Arrays.asList("SHIPTOCITY", "SHIPTOSTATE", "SHIPTOZIP", "SOLDTOCITY", "SOLDTOSTATE", "SOLDTOZIP")); //字段直接匹配 checkNonAddressFields(pdfText, dataNode, results, addressFields); //连续匹配 checkAddressFields(pdfText, dataNode, results, addressFields); return results; } /** * 检查 JSON 中非地址字段是否严格存在于 PDF 文本中 */ private void checkNonAddressFields(String pdfText, JsonNode jsonConfig, List<ValidationResult> results, Set<String> addressFields) { Iterator<Map.Entry<String, JsonNode>> fields = jsonConfig.fields(); while (fields.hasNext()) { Map.Entry<String, JsonNode> entry = fields.next(); String fieldName = entry.getKey(); JsonNode valueNode = entry.getValue(); if (valueNode.isValueNode() && !addressFields.contains(fieldName)) { String expectedValue = valueNode.asText().trim(); if (expectedValue.isEmpty()) continue; // 使用正则表达式进行严格匹配 String regex = "\\b" + Pattern.quote(expectedValue) + "\\b"; Pattern pattern = getCachedPattern(regex); Matcher matcher = pattern.matcher(pdfText); boolean found = matcher.find(); results.add(new ValidationResult( "FIELD", fieldName, expectedValue, found ? "Found" : "Not Found", found )); } } } /** * 获取或创建缓存中的 Pattern 对象 */ private Pattern getCachedPattern(String regex) { return patternCache.computeIfAbsent(regex, Pattern::compile); } /** * 检查 JSON 中地址字段是否严格存在于 PDF 文本中 */ private void checkAddressFields(String pdfText, JsonNode jsonConfig, List<ValidationResult> results, Set<String> addressFields) { List<Term> terms = HanLP.segment(pdfText); List<String> addressParts = new ArrayList<>(); for (Term term : terms) { String word = term.word; if (word.matches("\\d{5,7}")) { addressParts.add(word); } else if (term.nature.toString().startsWith("ns")) { addressParts.add(word); } } // 遍历 JSON 配置中的地址字段 Iterator<Map.Entry<String, JsonNode>> fields = jsonConfig.fields(); while (fields.hasNext()) { Map.Entry<String, JsonNode> entry = fields.next(); String fieldName = entry.getKey(); JsonNode valueNode = entry.getValue(); if (valueNode.isValueNode() && addressFields.contains(fieldName)) { String expectedValue = valueNode.asText().trim(); if (expectedValue.isEmpty()) continue; boolean found = false; for (String part : addressParts) { if (part.equals(expectedValue)) { found = true; break; } } results.add(new ValidationResult( "FIELD", fieldName, expectedValue, found ? "Found" : "Not Found", found )); } } } } 我的pdf读取文件 可以比较和校验json 但是我的图片 只可以读取内容信息 没办法校验比较 帮我修改一个
07-08
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