使用Apache POI基于csv表更新Excel工作表值
我还是java新手。 我对java语法有点问题。 我的程序应该执行以下过程：
1）它将csv文件作为输入。
2）它将excel文件作为输入。
3）它应该迭代写入日期的两个文件的第一列。
4）通过添加csv表中的信息来更新excel文件并保存其更改。
我有一个https://onedrive.live.com/?cid=24b4fceb4f4e4098&id=24B4FCEB4F4E4098%213018&authkey=%21AKKzaZsJ5pkd5NE
我有两个输入示例，结果excel表应该如何。
两个输入文件：
出口的CSV input.csv
出口Excel的input.xlsx
更新的excel文件应如下所示：
出口Excel的output.xlsx
我的Java代码：
import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.Reader; import java.nio.file.Files; import java.nio.file.Paths; import java.util.ArrayList; import java.util.List; import org.apache.commons.csv.CSVFormat; import org.apache.commons.csv.CSVParser; import org.apache.commons.csv.CSVRecord; import org.apache.poi.openxml4j.exceptions.InvalidFormatException; import org.apache.poi.ss.usermodel.Cell; import org.apache.poi.ss.usermodel.DataFormatter; import org.apache.poi.ss.usermodel.Row; import org.apache.poi.xssf.usermodel.XSSFSheet; import org.apache.poi.xssf.usermodel.XSSFWorkbook; public class CsvToExcelConverter { public static final String SAMPLE_XLSX_FILE_PATH = "C:/Users/blawand/Desktop/CSV_to_Excel/export-excel-test.xlsx"; public static final String SAMPLE_CSV_FILE_PATH = "C:/Users/blawand/Desktop/CSV_to_Excel/export-csv-test.csv"; public static List dates_csv = new ArrayList(); public static List dates_excel = new ArrayList(); public static void main(String[] args) throws IOException, InvalidFormatException { try (Reader reader = Files.newBufferedReader(Paths.get(SAMPLE_CSV_FILE_PATH)); CSVParser csvParser = new CSVParser(reader, CSVFormat.DEFAULT);) { for (CSVRecord csvRecord : csvParser) { // Accessing Values by Column Index String name = csvRecord.get(0); dates_csv.add(name); } dates_csv.remove(0); } FileInputStream fsIP = new FileInputStream(new File(SAMPLE_XLSX_FILE_PATH)); /* * ================================================================== Iterating over all the * rows and columns in a Sheet (Multiple ways) * ================================================================== */ // Getting the Sheet at index zero XSSFWorkbook workbook = new XSSFWorkbook(fsIP); XSSFSheet sheet = workbook.getSheetAt(0); // Get the Cell at index 2 from the above row // Cell cell1 = sheet.getRow(1).getCell(0); // for (int i = 0; i < dates_excel.size(); i++) { // XSSFRow rowtest = sheet.createRow((short) i + 1); // rowtest.createCell(0).setCellValue(dates_csv.get(i)); // // } // cell1.setCellValue(dates_csv.get(0)); // Create a DataFormatter to format and get each cell's value as String DataFormatter dataFormatter = new DataFormatter(); for (int rowIndex = 1; rowIndex <= sheet.getLastRowNum(); rowIndex++) { Row row = sheet.getRow(rowIndex); if (row != null) { Cell cell = row.getCell(0); // getColumn(0) if (cell != null) { // Found column and there is value in the cell. // String cellValueMaybeNull = cell.getStringCellValue(); String cellValueMaybeNull = dataFormatter.formatCellValue(cell); // String to number set dates_excel.add(cellValueMaybeNull); } } } System.out.println(dates_csv); System.out.println(dates_csv.size()); System.out.println(dates_excel); System.out.println(dates_excel.size()); while (dates_excel == dates_excel) { System.out.println("Yes"); break; } fsIP.close(); FileOutputStream output_file = new FileOutputStream(new File(SAMPLE_XLSX_FILE_PATH)); workbook.write(output_file); output_file.close(); } } 我已经阅读了这两个文件，但是我在更新excel文件并将项目名称添加到正确的日期时遇到了问题。 并且如果在csv表中已经写了两次或更多次相同的日期。
您还想知道哪些信息？
我会感谢每一个帮助或建议！
我有一个例子，主要由代码注释解释。 不过，代码基本上做了以下事情：
在构造函数中获取xlsx和csv文件的文件路径。
更新时，它首先将csv文件的内容读入Map ，其中LocalDate为键， List为值。
然后它遍历工作簿的行，跳过标题行并将第一列中的日期与Map的键进行比较。 如果映射包含该键，它将开始检查该行中的单元格以获取当前值，并将它们保留在列表中，以便以后不再写入它们。
然后它开始将值写入具有关键日期的行的单元格中。
我希望这有帮助。
import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.nio.file.Files; import java.nio.file.Path; import java.nio.file.Paths; import java.time.Instant; import java.time.LocalDate; import java.time.ZoneId; import java.time.format.DateTimeFormatter; import java.util.ArrayList; import java.util.Arrays; import java.util.Date; import java.util.Iterator; import java.util.List; import java.util.Map; import java.util.TreeMap; import org.apache.poi.ss.usermodel.Cell; import org.apache.poi.ss.usermodel.Row; import org.apache.poi.xssf.usermodel.XSSFRow; import org.apache.poi.xssf.usermodel.XSSFSheet; import org.apache.poi.xssf.usermodel.XSSFWorkbook; public class CsvXlsxUpdater { private static final DateTimeFormatter DATE_TIME_FORMATTER_CSV = DateTimeFormatter.ofPattern("dd.MM.yyyy"); private Path csvFilePath; private Path xlsxFilePath; private XSSFWorkbook workbook; private XSSFSheet sheet; private Map> csvContent = new TreeMap>(); private ZoneId zoneId = ZoneId.systemDefault(); public CsvXlsxUpdater(String pathToCsvFile, String pathToXlsxFile) { csvFilePath = Paths.get(pathToCsvFile); xlsxFilePath = Paths.get(pathToXlsxFile); } /** * Reads the content of the csv file into the corresponding class variable, * which is a {@link TreeMap} that has a {@link LocalDate} as key and a * {@link List } as values. */ private void readCsvContent() { List csvLines; try { csvLines = Files.readAllLines(csvFilePath); for (int i = 1; i < csvLines.size(); i++) { String line = csvLines.get(i); String[] splitValues = line.split(","); if (splitValues.length > 1) { List lineValues = Arrays.asList(splitValues); List projects = getProjectValuesFrom(lineValues); LocalDate localDate = LocalDate.parse(lineValues.get(0), DATE_TIME_FORMATTER_CSV); if (csvContent.containsKey(localDate)) { projects.forEach((String project) -> { List csvProjects = csvContent.get(localDate); if (!csvProjects.contains(project)) { csvProjects.add(project); } }); } else { csvContent.put(localDate, projects); } } else { LocalDate localDate = LocalDate.parse(splitValues[0], DATE_TIME_FORMATTER_CSV); csvContent.put(localDate, new ArrayList ()); } } } catch (IOException e) { System.err.println("CANNOT FIND OR READ CSV FILE: " + e.getMessage()); e.printStackTrace(); } catch (UnsupportedOperationException e) { System.err.println("UNSUPPORTED OPERATION: " + e.getMessage()); e.printStackTrace(); } } /** * Gets the corresponding {@link LocalDate} from a given (and deprecated) * {@link Date} * * @param date the deprecated {@link Date} object * @return the corresponding {@link LocalDate} */ private LocalDate parseLocalDateFrom(Date date) { Instant instantDate = date.toInstant(); return instantDate.atZone(zoneId).toLocalDate(); } /** * Takes a list of read values from the csv file and returns a list containing * all the values of the given list except from the first * element, which is a {@link String} representation of a date and * should be treated differently in this context. * * @param values the original list of {@link String}s * @return another list without the first element of the given list */ private List getProjectValuesFrom(List values) { List projectValues = new ArrayList (); for (int i = 1; i < values.size(); i++) { String value = values.get(i); if (!value.equals("")) { projectValues.add(value); } } return projectValues; } /** * Updates the workbook with the values read from the csv file */ public void updateWorkbook() { readCsvContent(); try { FileInputStream fis = new FileInputStream(xlsxFilePath.toAbsolutePath().toString()); workbook = new XSSFWorkbook(fis); sheet = workbook.getSheetAt(0); // iterate over the rows Iterator rowIterator = sheet.rowIterator(); while (rowIterator.hasNext()) { XSSFRow row = (XSSFRow) rowIterator.next(); if (row.getRowNum() == 0) { // skip this or set updated headers } else { // check if the csvContent contains the value of cell(0) LocalDate dateKey = parseLocalDateFrom(row.getCell(0).getDateCellValue()); if (csvContent.containsKey(dateKey)) { // if yes, get list-value of the key List values = csvContent.get(dateKey); // check if there are values if (values != null) { if (values.size() > 0) { // if there are, then go checking the cell values List projectsInXlsx = new ArrayList (); Iterator| cellIterator = row.cellIterator(); int lastColumnIndex = 1; // go through all cells with a value except from the first one while (cellIterator.hasNext()) { Cell cell = cellIterator.next(); // skip the first column as it contains the date if (cell.getColumnIndex() != 0) { lastColumnIndex = cell.getColumnIndex(); System.out.println("Accessing cell in column " + lastColumnIndex); // if there is a cell with a value if (cell.getStringCellValue() != null) { if (!cell.getStringCellValue().equals("")) { // check if the value in the cell is also in the csv values if (values.contains(cell.getStringCellValue())) { projectsInXlsx.add(cell.getStringCellValue()); lastColumnIndex++; } } } } } // now go through the values of the csv file int offset = 0; // cell column offset for more than one entry per date for (String value : values) { if (!projectsInXlsx.contains(value)) { // create a cell after the last one with a value row.createCell(lastColumnIndex + offset).setCellValue(value); offset++; } } } } } } } fis.close(); FileOutputStream fileOutputStream = new FileOutputStream(xlsxFilePath.toAbsolutePath().toString()); workbook.write(fileOutputStream); fileOutputStream.flush(); fileOutputStream.close(); workbook.close(); } catch (IOException e) { e.printStackTrace(); } } } |
在main方法中，您只需调用构造函数，将文件路径作为String传递，然后调用updateWorkbook()方法，因为它在内部首先读取csv。
例：
public class CsvXlsxMain { private static final String CSV_FILE_PATH = "S:\\ome\\example\\path\\to\\csv-input.csv"; private static final String XLSX_FILE_PATH = "S:\\ome\\example\\path\\to\\excel-input.xlsx"; public static void main(String[] args) { CsvXlsxUpdater cxu = new CsvXlsxUpdater(CSV_FILE_PATH, XLSX_FILE_PATH); cxu.updateWorkbook(); } }
请记住，此代码未经过全面测试 ，未来可能存在交换资源的问题如果需要，请使用符合您要求的各种xlsx和csv输入进行测试。
我没有使用任何库来解析csv文件！
我希望这对你有所帮助……