Java最全Java实现Excel导入和导出，看这一篇就够了(珍藏版)，Java架构师教你如何突破瓶颈
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另外，给大家安排了一波学习面试资料：
以上就是本文的全部内容，希望对大家的面试有所帮助，祝大家早日升职加薪迎娶白富美走上人生巅峰！
Map<Integer, String> uniqueMap = new HashMap<>(16);
for (int i = 0; i < array.size(); i++) {
list.add(getBean(clazz, array.getJSONObject(i), uniqueMap));
}
return list;
}
/**
* 获取每个对象的数据
*/
private static <T> T getBean(Class<T> c, JSONObject obj, Map<Integer, String> uniqueMap) throws Exception {
T t = c.newInstance();
Field[] fields = c.getDeclaredFields();
List<String> errMsgList = new ArrayList<>();
boolean hasRowTipsField = false;
StringBuilder uniqueBuilder = new StringBuilder();
int rowNum = 0;
for (Field field : fields) {
// 行号
if (field.getName().equals(ROW_NUM)) {
rowNum = obj.getInteger(ROW_NUM);
field.setAccessible(true);
field.set(t, rowNum);
continue;
}
// 是否需要设置异常信息
if (field.getName().equals(ROW_TIPS)) {
hasRowTipsField = true;
continue;
}
// 原始数据
if (field.getName().equals(ROW_DATA)) {
field.setAccessible(true);
field.set(t, obj.toString());
continue;
}
// 设置对应属性值
setFieldValue(t, field, obj, uniqueBuilder, errMsgList);
}
// 数据唯一性校验
if (uniqueBuilder.length() > 0) {
if (uniqueMap.containsValue(uniqueBuilder.toString())) {
Set<Integer> rowNumKeys = uniqueMap.keySet();
for (Integer num : rowNumKeys) {
if (uniqueMap.get(num).equals(uniqueBuilder.toString())) {
errMsgList.add(String.format("数据唯一性校验失败,(%s)与第%s行重复)", uniqueBuilder, num));
}
}
} else {
uniqueMap.put(rowNum, uniqueBuilder.toString());
}
}
// 失败处理
if (errMsgList.isEmpty() && !hasRowTipsField) {
return t;
}
StringBuilder sb = new StringBuilder();
int size = errMsgList.size();
for (int i = 0; i < size; i++) {
if (i == size - 1) {
sb.append(errMsgList.get(i));
} else {
sb.append(errMsgList.get(i)).append(";");
}
}
// 设置错误信息
for (Field field : fields) {
if (field.getName().equals(ROW_TIPS)) {
field.setAccessible(true);
field.set(t, sb.toString());
}
}
return t;
}
private static <T> void setFieldValue(T t, Field field, JSONObject obj, StringBuilder uniqueBuilder, List<String> errMsgList) {
// 获取 ExcelImport 注解属性
ExcelImport annotation = field.getAnnotation(ExcelImport.class);
if (annotation == null) {
return;
}
String cname = annotation.value();
if (cname.trim().length() == 0) {
return;
}
// 获取具体值
String val = null;
if (obj.containsKey(cname)) {
val = getString(obj.getString(cname));
}
if (val == null) {
return;
}
field.setAccessible(true);
// 判断是否必填
boolean require = annotation.required();
if (require && val.isEmpty()) {
errMsgList.add(String.format("[%s]不能为空", cname));
return;
}
// 数据唯一性获取
boolean unique = annotation.unique();
if (unique) {
if (uniqueBuilder.length() > 0) {
uniqueBuilder.append("--").append(val);
} else {
uniqueBuilder.append(val);
}
}
// 判断是否超过最大长度
int maxLength = annotation.maxLength();
if (maxLength > 0 && val.length() > maxLength) {
errMsgList.add(String.format("[%s]长度不能超过%s个字符(当前%s个字符)", cname, maxLength, val.length()));
}
// 判断当前属性是否有映射关系
LinkedHashMap<String, String> kvMap = getKvMap(annotation.kv());
if (!kvMap.isEmpty()) {
boolean isMatch = false;
for (String key : kvMap.keySet()) {
if (kvMap.get(key).equals(val)) {
val = key;
isMatch = true;
break;
}
}
if (!isMatch) {
errMsgList.add(String.format("[%s]的值不正确(当前值为%s)", cname, val));
return;
}
}
// 其余情况根据类型赋值
String fieldClassName = field.getType().getSimpleName();
try {
if ("String".equalsIgnoreCase(fieldClassName)) {
field.set(t, val);
} else if ("boolean".equalsIgnoreCase(fieldClassName)) {
field.set(t, Boolean.valueOf(val));
} else if ("int".equalsIgnoreCase(fieldClassName) || "Integer".equals(fieldClassName)) {
try {
field.set(t, Integer.valueOf(val));
} catch (NumberFormatException e) {
errMsgList.add(String.format("[%s]的值格式不正确(当前值为%s)", cname, val));
}
} else if ("double".equalsIgnoreCase(fieldClassName)) {
field.set(t, Double.valueOf(val));
} else if ("long".equalsIgnoreCase(fieldClassName)) {
field.set(t, Long.valueOf(val));
} else if ("BigDecimal".equalsIgnoreCase(fieldClassName)) {
field.set(t, new BigDecimal(val));
}
} catch (Exception e) {
e.printStackTrace();
}
}
private static Map<String, JSONArray> readExcelManySheet(MultipartFile mFile, File file) throws IOException {
Workbook book = getWorkbook(mFile, file);
if (book == null) {
return Collections.emptyMap();
}
Map<String, JSONArray> map = new LinkedHashMap<>();
for (int i = 0; i < book.getNumberOfSheets(); i++) {
Sheet sheet = book.getSheetAt(i);
JSONArray arr = readSheet(sheet);
map.put(sheet.getSheetName(), arr);
}
book.close();
return map;
}
private static JSONArray readExcel(MultipartFile mFile, File file) throws IOException {
Workbook book = getWorkbook(mFile, file);
if (book == null) {
return new JSONArray();
}
JSONArray array = readSheet(book.getSheetAt(0));
book.close();
return array;
}
private static Workbook getWorkbook(MultipartFile mFile, File file) throws IOException {
boolean fileNotExist = (file == null || !file.exists());
if (mFile == null && fileNotExist) {
return null;
}
// 解析表格数据
InputStream in;
String fileName;
if (mFile != null) {
// 上传文件解析
in = mFile.getInputStream();
fileName = getString(mFile.getOriginalFilename()).toLowerCase();
} else {
// 本地文件解析
in = new FileInputStream(file);
fileName = file.getName().toLowerCase();
}
Workbook book;
if (fileName.endsWith(XLSX)) {
book = new XSSFWorkbook(in);
} else if (fileName.endsWith(XLS)) {
POIFSFileSystem poifsFileSystem = new POIFSFileSystem(in);
book = new HSSFWorkbook(poifsFileSystem);
} else {
return null;
}
in.close();
return book;
}
private static JSONArray readSheet(Sheet sheet) {
// 首行下标
int rowStart = sheet.getFirstRowNum();
// 尾行下标
int rowEnd = sheet.getLastRowNum();
// 获取表头行
Row headRow = sheet.getRow(rowStart);
if (headRow == null) {
return new JSONArray();
}
int cellStart = headRow.getFirstCellNum();
int cellEnd = headRow.getLastCellNum();
Map<Integer, String> keyMap = new HashMap<>();
for (int j = cellStart; j < cellEnd; j++) {
// 获取表头数据
String val = getCellValue(headRow.getCell(j));
if (val != null && val.trim().length() != 0) {
keyMap.put(j, val);
}
}
// 如果表头没有数据则不进行解析
if (keyMap.isEmpty()) {
return (JSONArray) Collections.emptyList();
}
// 获取每行JSON对象的值
JSONArray array = new JSONArray();
// 如果首行与尾行相同，表明只有一行，返回表头数据
if (rowStart == rowEnd) {
JSONObject obj = new JSONObject();
// 添加行号
obj.put(ROW_NUM, 1);
for (int i : keyMap.keySet()) {
obj.put(keyMap.get(i), "");
}
array.add(obj);
return array;
}
for (int i = rowStart + 1; i <= rowEnd; i++) {
Row eachRow = sheet.getRow(i);
JSONObject obj = new JSONObject();
// 添加行号
obj.put(ROW_NUM, i + 1);
StringBuilder sb = new StringBuilder();
for (int k = cellStart; k < cellEnd; k++) {
if (eachRow != null) {
String val = getCellValue(eachRow.getCell(k));
// 所有数据添加到里面，用于判断该行是否为空
sb.append(val);
obj.put(keyMap.get(k), val);
}
}
if (sb.length() > 0) {
array.add(obj);
}
}
return array;
}
private static String getCellValue(Cell cell) {
// 空白或空
if (cell == null || cell.getCellTypeEnum() == CellType.BLANK) {
return "";
}
// String类型
if (cell.getCellTypeEnum() == CellType.STRING) {
String val = cell.getStringCellValue();
if (val == null || val.trim().length() == 0) {
return "";
}
return val.trim();
}
// 数字类型
if (cell.getCellTypeEnum() == CellType.NUMERIC) {
String s = cell.getNumericCellValue() + "";
// 去掉尾巴上的小数点0
if (Pattern.matches(".*\\.0*", s)) {
return s.split("\\.")[0];
} else {
return s;
}
}
// 布尔值类型
if (cell.getCellTypeEnum() == CellType.BOOLEAN) {
return cell.getBooleanCellValue() + "";
}
// 错误类型
return cell.getCellFormula();
}
public static <T> void exportTemplate(HttpServletResponse response, String fileName, Class<T> clazz) {
exportTemplate(response, fileName, fileName, clazz, false);
}
public static <T> void exportTemplate(HttpServletResponse response, String fileName, String sheetName,
Class<T> clazz) {
exportTemplate(response, fileName, sheetName, clazz, false);
}
public static <T> void exportTemplate(HttpServletResponse response, String fileName, Class<T> clazz,
boolean isContainExample) {
exportTemplate(response, fileName, fileName, clazz, isContainExample);
}
public static <T> void exportTemplate(HttpServletResponse response, String fileName, String sheetName,
Class<T> clazz, boolean isContainExample) {
// 获取表头字段
List<ExcelClassField> headFieldList = getExcelClassFieldList(clazz);
// 获取表头数据和示例数据
List<List<Object>> sheetDataList = new ArrayList<>();
List<Object> headList = new ArrayList<>();
List<Object> exampleList = new ArrayList<>();
Map<Integer, List<String>> selectMap = new LinkedHashMap<>();
for (int i = 0; i < headFieldList.size(); i++) {
ExcelClassField each = headFieldList.get(i);
headList.add(each.getName());
exampleList.add(each.getExample());
LinkedHashMap<String, String> kvMap = each.getKvMap();
if (kvMap != null && kvMap.size() > 0) {
selectMap.put(i, new ArrayList<>(kvMap.values()));
}
}
sheetDataList.add(headList);
if (isContainExample) {
sheetDataList.add(exampleList);
}
// 导出数据
export(response, fileName, sheetName, sheetDataList, selectMap);
}
private static <T> List<ExcelClassField> getExcelClassFieldList(Class<T> clazz) {
// 解析所有字段
Field[] fields = clazz.getDeclaredFields();
boolean hasExportAnnotation = false;
Map<Integer, List<ExcelClassField>> map = new LinkedHashMap<>();
List<Integer> sortList = new ArrayList<>();
for (Field field : fields) {
ExcelClassField cf = getExcelClassField(field);
if (cf.getHasAnnotation() == 1) {
hasExportAnnotation = true;
}
int sort = cf.getSort();
if (map.containsKey(sort)) {
map.get(sort).add(cf);
} else {
List<ExcelClassField> list = new ArrayList<>();
list.add(cf);
sortList.add(sort);
map.put(sort, list);
}
}
Collections.sort(sortList);
// 获取表头
List<ExcelClassField> headFieldList = new ArrayList<>();
if (hasExportAnnotation) {
for (Integer sort : sortList) {
for (ExcelClassField cf : map.get(sort)) {
if (cf.getHasAnnotation() == 1) {
headFieldList.add(cf);
}
}
}
} else {
headFieldList.addAll(map.get(0));
}
return headFieldList;
}
private static ExcelClassField getExcelClassField(Field field) {
ExcelClassField cf = new ExcelClassField();
String fieldName = field.getName();
cf.setFieldName(fieldName);
ExcelExport annotation = field.getAnnotation(ExcelExport.class);
// 无 ExcelExport 注解情况
if (annotation == null) {
cf.setHasAnnotation(0);
cf.setName(fieldName);
cf.setSort(0);
return cf;
}
// 有 ExcelExport 注解情况
cf.setHasAnnotation(1);
cf.setName(annotation.value());
String example = getString(annotation.example());
if (!example.isEmpty()) {
if (isNumeric(example)) {
cf.setExample(Double.valueOf(example));
} else {
cf.setExample(example);
}
} else {
cf.setExample("");
}
cf.setSort(annotation.sort());
// 解析映射
String kv = getString(annotation.kv());
cf.setKvMap(getKvMap(kv));
return cf;
}
private static LinkedHashMap<String, String> getKvMap(String kv) {
LinkedHashMap<String, String> kvMap = new LinkedHashMap<>();
if (kv.isEmpty()) {
return kvMap;
}
String[] kvs = kv.split(";");
if (kvs.length == 0) {
return kvMap;
}
for (String each : kvs) {
String[] eachKv = getString(each).split("-");
if (eachKv.length != 2) {
continue;
}
String k = eachKv[0];
String v = eachKv[1];
if (k.isEmpty() || v.isEmpty()) {
continue;
}
kvMap.put(k, v);
}
return kvMap;
}
/**
* 导出表格到本地
*
* @param file 本地文件对象
* @param sheetData 导出数据
*/
public static void exportFile(File file, List<List<Object>> sheetData) {
if (file == null) {
System.out.println("文件创建失败");
return;
}
if (sheetData == null) {
sheetData = new ArrayList<>();
}
Map<String, List<List<Object>>> map = new HashMap<>();
map.put(file.getName(), sheetData);
export(null, file, file.getName(), map, null);
}
/**
* 导出表格到本地
*
* @param <T> 导出数据类似，和K类型保持一致
* @param filePath 文件父路径（如：D:/doc/excel/）
* @param fileName 文件名称（不带尾缀，如：学生表）
* @param list 导出数据
* @throws IOException IO异常
*/
public static <T> File exportFile(String filePath, String fileName, List<T> list) throws IOException {
File file = getFile(filePath, fileName);
List<List<Object>> sheetData = getSheetData(list);
exportFile(file, sheetData);
return file;
}
/**
* 获取文件
*
* @param filePath filePath 文件父路径（如：D:/doc/excel/）
* @param fileName 文件名称（不带尾缀，如：用户表）
* @return 本地File文件对象
*/
private static File getFile(String filePath, String fileName) throws IOException {
String dirPath = getString(filePath);
String fileFullPath;
if (dirPath.isEmpty()) {
fileFullPath = fileName;
} else {
// 判定文件夹是否存在，如果不存在，则级联创建
File dirFile = new File(dirPath);
if (!dirFile.exists()) {
dirFile.mkdirs();
}
// 获取文件夹全名
if (dirPath.endsWith(String.valueOf(LEAN_LINE))) {
fileFullPath = dirPath + fileName + XLSX;
} else {
fileFullPath = dirPath + LEAN_LINE + fileName + XLSX;
}
}
System.out.println(fileFullPath);
File file = new File(fileFullPath);
if (!file.exists()) {
file.createNewFile();
}
return file;
}
private static <T> List<List<Object>> getSheetData(List<T> list) {
// 获取表头字段
List<ExcelClassField> excelClassFieldList = getExcelClassFieldList(list.get(0).getClass());
List<String> headFieldList = new ArrayList<>();
List<Object> headList = new ArrayList<>();
Map<String, ExcelClassField> headFieldMap = new HashMap<>();
for (ExcelClassField each : excelClassFieldList) {
String fieldName = each.getFieldName();
headFieldList.add(fieldName);
headFieldMap.put(fieldName, each);
headList.add(each.getName());
}
// 添加表头名称
List<List<Object>> sheetDataList = new ArrayList<>();
sheetDataList.add(headList);
// 获取表数据
for (T t : list) {
Map<String, Object> fieldDataMap = getFieldDataMap(t);
Set<String> fieldDataKeys = fieldDataMap.keySet();
List<Object> rowList = new ArrayList<>();
for (String headField : headFieldList) {
if (!fieldDataKeys.contains(headField)) {
continue;
}
Object data = fieldDataMap.get(headField);
if (data == null) {
rowList.add("");
continue;
}
ExcelClassField cf = headFieldMap.get(headField);
// 判断是否有映射关系
LinkedHashMap<String, String> kvMap = cf.getKvMap();
if (kvMap == null || kvMap.isEmpty()) {
rowList.add(data);
continue;
}
String val = kvMap.get(data.toString());
if (isNumeric(val)) {
rowList.add(Double.valueOf(val));
} else {
rowList.add(val);
}
}
sheetDataList.add(rowList);
}
return sheetDataList;
}
private static <T> Map<String, Object> getFieldDataMap(T t) {
Map<String, Object> map = new HashMap<>();
Field[] fields = t.getClass().getDeclaredFields();
try {
for (Field field : fields) {
String fieldName = field.getName();
field.setAccessible(true);
Object object = field.get(t);
map.put(fieldName, object);
}
} catch (IllegalArgumentException | IllegalAccessException e) {
e.printStackTrace();
}
return map;
}
public static void exportEmpty(HttpServletResponse response, String fileName) {
List<List<Object>> sheetDataList = new ArrayList<>();
List<Object> headList = new ArrayList<>();
headList.add("导出无数据");
sheetDataList.add(headList);
export(response, fileName, sheetDataList);
}
public static void export(HttpServletResponse response, String fileName, List<List<Object>> sheetDataList) {
export(response, fileName, fileName, sheetDataList, null);
}
public static void exportManySheet(HttpServletResponse response, String fileName, Map<String, List<List<Object>>> sheetMap) {
export(response, null, fileName, sheetMap, null);
}
public static void export(HttpServletResponse response, String fileName, String sheetName,
List<List<Object>> sheetDataList) {
export(response, fileName, sheetName, sheetDataList, null);
}
public static void export(HttpServletResponse response, String fileName, String sheetName,
List<List<Object>> sheetDataList, Map<Integer, List<String>> selectMap) {
Map<String, List<List<Object>>> map = new HashMap<>();
map.put(sheetName, sheetDataList);
export(response, null, fileName, map, selectMap);
}
public static <T, K> void export(HttpServletResponse response, String fileName, List<T> list, Class<K> template) {
// list 是否为空
boolean lisIsEmpty = list == null || list.isEmpty();
// 如果模板数据为空，且导入的数据为空，则导出空文件
if (template == null && lisIsEmpty) {
exportEmpty(response, fileName);
return;
}
// 如果 list 数据，则导出模板数据
if (lisIsEmpty) {
exportTemplate(response, fileName, template);
return;
}
// 导出数据
List<List<Object>> sheetDataList = getSheetData(list);
export(response, fileName, sheetDataList);
}
public static void export(HttpServletResponse response, String fileName, List<List<Object>> sheetDataList, Map<Integer, List<String>> selectMap) {
export(response, fileName, fileName, sheetDataList, selectMap);
}
private static void export(HttpServletResponse response, File file, String fileName,
Map<String, List<List<Object>>> sheetMap, Map<Integer, List<String>> selectMap) {
// 整个 Excel 表格 book 对象
SXSSFWorkbook book = new SXSSFWorkbook();
// 每个 Sheet 页
Set<Entry<String, List<List<Object>>>> entries = sheetMap.entrySet();
for (Entry<String, List<List<Object>>> entry : entries) {
List<List<Object>> sheetDataList = entry.getValue();
Sheet sheet = book.createSheet(entry.getKey());
Drawing<?> patriarch = sheet.createDrawingPatriarch();
// 设置表头背景色（灰色）
CellStyle headStyle = book.createCellStyle();
headStyle.setFillForegroundColor(IndexedColors.GREY_80_PERCENT.index);
headStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND);
headStyle.setAlignment(HorizontalAlignment.CENTER);
headStyle.setFillForegroundColor(IndexedColors.GREY_25_PERCENT.index);
// 设置表身背景色（默认色）
CellStyle rowStyle = book.createCellStyle();
rowStyle.setAlignment(HorizontalAlignment.CENTER);
rowStyle.setVerticalAlignment(VerticalAlignment.CENTER);
// 设置表格列宽度（默认为15个字节）
sheet.setDefaultColumnWidth(15);
// 创建合并算法数组
int rowLength = sheetDataList.size();
int columnLength = sheetDataList.get(0).size();
int[][] mergeArray = new int[rowLength][columnLength];
for (int i = 0; i < sheetDataList.size(); i++) {
// 每个 Sheet 页中的行数据
Row row = sheet.createRow(i);
List<Object> rowList = sheetDataList.get(i);
for (int j = 0; j < rowList.size(); j++) {
// 每个行数据中的单元格数据
Object o = rowList.get(j);
int v = 0;
if (o instanceof URL) {
// 如果要导出图片的话, 链接需要传递 URL 对象
setCellPicture(book, row, patriarch, i, j, (URL) o);
} else {
Cell cell = row.createCell(j);
if (i == 0) {
// 第一行为表头行，采用灰色底背景
v = setCellValue(cell, o, headStyle);
} else {
// 其他行为数据行，默认白底色
v = setCellValue(cell, o, rowStyle);
}
}
mergeArray[i][j] = v;
}
}
// 合并单元格
mergeCells(sheet, mergeArray);
// 设置下拉列表
setSelect(sheet, selectMap);
}
// 写数据
if (response != null) {
// 前端导出
try {
write(response, book, fileName);
} catch (IOException e) {
e.printStackTrace();
}
} else {
// 本地导出
FileOutputStream fos;
try {
fos = new FileOutputStream(file);
ByteArrayOutputStream ops = new ByteArrayOutputStream();
book.write(ops);
fos.write(ops.toByteArray());
fos.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
/**
* 合并当前Sheet页的单元格
*
* @param sheet 当前 sheet 页
* @param mergeArray 合并单元格算法
*/
private static void mergeCells(Sheet sheet, int[][] mergeArray) {
// 横向合并
for (int x = 0; x < mergeArray.length; x++) {
int[] arr = mergeArray[x];
boolean merge = false;
int y1 = 0;
int y2 = 0;
for (int y = 0; y < arr.length; y++) {
int value = arr[y];
if (value == CELL_COLUMN_MERGE) {
if (!merge) {
y1 = y;
}
y2 = y;
merge = true;
} else {
merge = false;
if (y1 > 0) {
sheet.addMergedRegion(new CellRangeAddress(x, x, (y1 - 1), y2));
}
y1 = 0;
y2 = 0;
}
}
if (y1 > 0) {
sheet.addMergedRegion(new CellRangeAddress(x, x, (y1 - 1), y2));
}
}
// 纵向合并
int xLen = mergeArray.length;
int yLen = mergeArray[0].length;
for (int y = 0; y < yLen; y++) {
boolean merge = false;
int x1 = 0;
int x2 = 0;
for (int x = 0; x < xLen; x++) {
int value = mergeArray[x][y];
if (value == CELL_ROW_MERGE) {
if (!merge) {
x1 = x;
}
x2 = x;
merge = true;
} else {
merge = false;
if (x1 > 0) {
sheet.addMergedRegion(new CellRangeAddress((x1 - 1), x2, y, y));
}
x1 = 0;
x2 = 0;
}
}
if (x1 > 0) {
sheet.addMergedRegion(new CellRangeAddress((x1 - 1), x2, y, y));
}
}
}
private static void write(HttpServletResponse response, SXSSFWorkbook book, String fileName) throws IOException {
response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
response.setCharacterEncoding("utf-8");
String name = new String(fileName.getBytes("GBK"), "ISO8859_1") + XLSX;
response.addHeader("Content-Disposition", "attachment;filename=" + name);
ServletOutputStream out = response.getOutputStream();
book.write(out);
out.flush();
out.close();
}
private static int setCellValue(Cell cell, Object o, CellStyle style) {
// 设置样式
cell.setCellStyle(style);
// 数据为空时
if (o == null) {
cell.setCellType(CellType.STRING);
cell.setCellValue("");
return CELL_OTHER;
}
// 是否为字符串
if (o instanceof String) {
String s = o.toString();
if (isNumeric(s)) {
cell.setCellType(CellType.NUMERIC);
cell.setCellValue(Double.parseDouble(s));
return CELL_OTHER;
} else {
cell.setCellType(CellType.STRING);
cell.setCellValue(s);
}
if (s.equals(ROW_MERGE)) {
return CELL_ROW_MERGE;
} else if (s.equals(COLUMN_MERGE)) {
return CELL_COLUMN_MERGE;
} else {
return CELL_OTHER;
}
}
// 是否为字符串
if (o instanceof Integer || o instanceof Long || o instanceof Double || o instanceof Float) {
cell.setCellType(CellType.NUMERIC);
cell.setCellValue(Double.parseDouble(o.toString()));
return CELL_OTHER;
}
// 是否为Boolean
if (o instanceof Boolean) {
cell.setCellType(CellType.BOOLEAN);
cell.setCellValue((Boolean) o);
return CELL_OTHER;
}
// 如果是BigDecimal，则默认3位小数
if (o instanceof BigDecimal) {
cell.setCellType(CellType.NUMERIC);
cell.setCellValue(((BigDecimal) o).setScale(3, RoundingMode.HALF_UP).doubleValue());
return CELL_OTHER;
}
// 如果是Date数据，则显示格式化数据
if (o instanceof Date) {
cell.setCellType(CellType.STRING);
cell.setCellValue(formatDate((Date) o));
return CELL_OTHER;
}
// 如果是其他，则默认字符串类型
cell.setCellType(CellType.STRING);
cell.setCellValue(o.toString());
return CELL_OTHER;
}
private static void setCellPicture(SXSSFWorkbook wb, Row sr, Drawing<?> patriarch, int x, int y, URL url) {
// 设置图片宽高
sr.setHeight((short) (IMG_WIDTH * IMG_HEIGHT));
// （jdk1.7版本try中定义流可自动关闭）
try (InputStream is = url.openStream(); ByteArrayOutputStream outputStream = new ByteArrayOutputStream()) {
byte[] buff = new byte[BYTES_DEFAULT_LENGTH];
int rc;
while ((rc = is.read(buff, 0, BYTES_DEFAULT_LENGTH)) > 0) {
outputStream.write(buff, 0, rc);
}
// 设置图片位置
XSSFClientAnchor anchor = new XSSFClientAnchor(0, 0, 0, 0, y, x, y + 1, x + 1);
// 设置这个，图片会自动填满单元格的长宽
anchor.setAnchorType(AnchorType.MOVE_AND_RESIZE);
patriarch.createPicture(anchor, wb.addPicture(outputStream.toByteArray(), HSSFWorkbook.PICTURE_TYPE_JPEG));
} catch (Exception e) {
e.printStackTrace();
}
}
private static String formatDate(Date date) {
if (date == null) {
return "";
}
SimpleDateFormat format = new SimpleDateFormat(DATE_FORMAT);
return format.format(date);
}
private static void setSelect(Sheet sheet, Map<Integer, List<String>> selectMap) {
if (selectMap == null || selectMap.isEmpty()) {
return;
}
Set<Entry<Integer, List<String>>> entrySet = selectMap.entrySet();
for (Entry<Integer, List<String>> entry : entrySet) {
int y = entry.getKey();
List<String> list = entry.getValue();
if (list == null || list.isEmpty()) {
continue;
}
String[] arr = new String[list.size()];
for (int i = 0; i < list.size(); i++) {
arr[i] = list.get(i);
}
DataValidationHelper helper = sheet.getDataValidationHelper();
CellRangeAddressList addressList = new CellRangeAddressList(1, 65000, y, y);
DataValidationConstraint dvc = helper.createExplicitListConstraint(arr);
DataValidation dv = helper.createValidation(dvc, addressList);
if (dv instanceof HSSFDataValidation) {
dv.setSuppressDropDownArrow(false);
} else {
dv.setSuppressDropDownArrow(true);
dv.setShowErrorBox(true);
}
sheet.addValidationData(dv);
}
}
private static boolean isNumeric(String str) {
if ("0.0".equals(str)) {
return true;
}
for (int i = str.length(); --i >= 0; ) {
if (!Character.isDigit(str.charAt(i))) {
return false;
}
}
return true;
}
private static String getString(String s) {
if (s == null) {
return "";
}
if (s.isEmpty()) {
return s;
}
return s.trim();
}
}
### ExcelImport
package com.zyq.util.excel;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
-
@author sunnyzyq
-
@date 2021/12/17
*/
@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
public @interface ExcelImport {
/** 字段名称 */
String value();
/** 导出映射，格式如：0-未知;1-男;2-女 */
String kv() default "";
/** 是否为必填字段（默认为非必填） */
boolean required() default false;
/** 最大长度（默认255） */
int maxLength() default 255;
/** 导入唯一性验证（多个字段则取联合验证） */
boolean unique() default false;
}
### ExcelExport
package com.zyq.util.excel;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
-
@author sunnyzyq
-
@date 2021/12/17
*/
@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
public @interface ExcelExport {
/** 字段名称 */
String value();
/** 导出排序先后: 数字越小越靠前（默认按Java类字段顺序导出） */
int sort() default 0;
/** 导出映射，格式如：0-未知;1-男;2-女 */
String kv() default "";
/** 导出模板示例值（有值的话，直接取该值，不做映射） */
String example() default "";
}
### ExcelClassField
package com.zyq.util.excel;
import java.util.LinkedHashMap;
/**
-
@author sunnyzyq
-
@date 2021/12/17
*/
public class ExcelClassField {
/** 字段名称 */
private String fieldName;
/** 表头名称 */
private String name;
/** 映射关系 */
private LinkedHashMap<String, String> kvMap;
/** 示例值 */
private Object example;
/** 排序 */
private int sort;
/** 是否为注解字段：0-否，1-是 */
private int hasAnnotation;
public String getFieldName() {
return fieldName;
}
public void setFieldName(String fieldName) {
this.fieldName = fieldName;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public LinkedHashMap<String, String> getKvMap() {
return kvMap;
}
public void setKvMap(LinkedHashMap<String, String> kvMap) {
this.kvMap = kvMap;
}
public Object getExample() {
return example;
}
总结
面试前的“练手”还是很重要的，所以开始面试之前一定要准备好啊，不然也是耽搁面试官和自己的时间。
我自己是刷了不少面试题的，所以在面试过程中才能够做到心中有数，基本上会清楚面试过程中会问到哪些知识点，高频题又有哪些，所以刷题是面试前期准备过程中非常重要的一点。
面试题及解析总结
大厂面试场景
知识点总结
/
@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
public @interface ExcelExport {
/** 字段名称 */
String value();
/** 导出排序先后: 数字越小越靠前（默认按Java类字段顺序导出） */
int sort() default 0;
/** 导出映射，格式如：0-未知;1-男;2-女 */
String kv() default "";
/** 导出模板示例值（有值的话，直接取该值，不做映射） */
String example() default "";
}
### ExcelClassField
package com.zyq.util.excel;
import java.util.LinkedHashMap;
/**
-
@author sunnyzyq
-
@date 2021/12/17
*/
public class ExcelClassField {
/** 字段名称 */
private String fieldName;
/** 表头名称 */
private String name;
/** 映射关系 */
private LinkedHashMap<String, String> kvMap;
/** 示例值 */
private Object example;
/** 排序 */
private int sort;
/** 是否为注解字段：0-否，1-是 */
private int hasAnnotation;
public String getFieldName() {
return fieldName;
}
public void setFieldName(String fieldName) {
this.fieldName = fieldName;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public LinkedHashMap<String, String> getKvMap() {
return kvMap;
}
public void setKvMap(LinkedHashMap<String, String> kvMap) {
this.kvMap = kvMap;
}
public Object getExample() {
return example;
}
总结
面试前的“练手”还是很重要的，所以开始面试之前一定要准备好啊，不然也是耽搁面试官和自己的时间。
我自己是刷了不少面试题的，所以在面试过程中才能够做到心中有数，基本上会清楚面试过程中会问到哪些知识点，高频题又有哪些，所以刷题是面试前期准备过程中非常重要的一点。
面试题及解析总结
[外链图片转存中…(img-QZcxNxp8-1715312223400)]
大厂面试场景
[外链图片转存中…(img-QnXG4FzS-1715312223400)]
知识点总结
[外链图片转存中…(img-51FgV2ya-1715312223401)]
旨在为数千万中国开发者提供一个无缝且高效的云端环境，以支持学习、使用和贡献开源项目。
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