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首页 > 解决方案 > 如何使用具有通用数据类型的 printf/formatter 在 Java 和 POI 中的控制台中制作表格

java - 如何使用具有通用数据类型的 printf/formatter 在 Java 和 POI 中的控制台中制作表格

问题描述

我对堆栈溢出相当陌生，我正试图在我的控制台中创建一个表格，但是当我尝试printf用于填充或 javaFormatter时，我似乎无法将它放入我的代码中，因为单元格可以是任何类型。

package com.codeblit.IO;

import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

import java.io.File;
import java.io.IOException;
import java.util.Iterator;

public class ExcelReader {

    private XSSFWorkbook workbook;
    private XSSFSheet sheet;
    private DataFormatter formatter;
    private Cell cell;
    private int rowCount, columnCount, rowHeight;

    public ExcelReader(String filePath) {
        init(filePath);
    }

    private void init(String filePath){
        File src = new File(filePath);

        //POI = Poor Obfuscation Implementation
        //XSSF = use of xlsx format, from 2007 onwards
        //HSSF = use of xls format,  before 2007 and older
        //All indexes start at 0 including: sheets, columns, rows etc.

        try {
            workbook = new XSSFWorkbook(src); //The full workbook created from file
        } catch (IOException ioe){
            System.err.println("[ERROR]; Workbook couldn't be created from file due to IO!");
            ioe.printStackTrace();
        } catch (InvalidFormatException ife){
            System.err.println("[ERROR]: Workbook couldn't be created by file due to invalid formats!");
            ife.printStackTrace();
        }

        formatter = new DataFormatter();
    }

    public String readAsString(int sheetIndex, int row, int column){
        sheet = workbook.getSheetAt(sheetIndex); //The sheet at sheetIndex in the excel workbook
        cell = sheet.getRow(row).getCell(column); //select the row and column, get the cell

        return formatter.formatCellValue(cell); //return the value of the cell as a string even if it is numeric to avoid errors
    }

    public double readAsNumeric(int sheetIndex, int row, int column) {
        sheet = workbook.getSheetAt(sheetIndex); //The sheet at sheetIndex in the excel workbook

        return sheet.getRow(row).getCell(column).getNumericCellValue(); //select the row and column, and get the value as a double
    }

    public void printSheet(int sheetIndex){
        sheet = workbook.getSheetAt(sheetIndex);
        Iterator iterator = sheet.rowIterator(); //think of it as j for columns in multi dimensional arrays
        Row row; //the current row
        Cell cell;

        while (iterator.hasNext()) { //detect if there is a next column, this works as
            row = (Row) iterator.next();
            System.out.print("\n");

            for(int i = 0; i <= getRowCount(); i++){
                cell = row.getCell(i); //the current cell in the row
                System.out.print("\t\t\t");


                switch (cell.getCellType()) {
                    case STRING:
                        System.out.print(cell.getStringCellValue());
                        break;
                    case NUMERIC:
                        if(DateUtil.isCellDateFormatted(cell))
                            System.out.println(cell.getDateCellValue());
                        System.out.print(cell.getNumericCellValue());
                        break;
                    case BOOLEAN:
                        System.out.print(cell.getBooleanCellValue());
                        break;
                    case FORMULA:
                        System.out.print(cell.getCellFormula());
                        break;
                    case ERROR:
                        System.out.print(cell.getErrorCellValue());
                        break;
                    default:
                        System.out.print("Unidentified Cell Value: " + cell.getCellType());
                }
            }
        }
    }

    //********** GETTERS && SETTERS **********

    public int getRowCount() {
        //I set it here and not initialize so that every time we change the sheet and call this method again it will change the value instead of giving it the same one
        rowCount = sheet.getLastRowNum();
        return rowCount;
    }

//    1. int noOfColumns = sh.getRow(0).getPhysicalNumberOfCells();
//    2. int noOfColumns = sh.getRow(0).getLastCellNum();

//    There is a fine difference between them:
//    Option 1 gives the no of columns which are actually filled with contents(If the 2nd column of 10 columns is not filled you will get 9) it will replace it with blank lines/spaces
//    Option 2 just gives you the index of last column. Hence done 'getLastCellNum()'

    public int getColumnCount(int rowIndex) {
        //I set it here and not initialize so that every time we change the sheet and call this method again it will change the value instead of giving it the same one
        columnCount = sheet.getRow(rowIndex).getLastCellNum();
        return columnCount;
    }

    public int getRowHeight(Row row) {
        rowHeight = row.getHeight();
        return rowHeight;
    }

}

重点在哪里：

while (iterator.hasNext()) { //detect if there is a next column, this works as
    row = (Row) iterator.next();
    System.out.print("\n");

    for(int i = 0; i <= getRowCount(); i++){
        cell = row.getCell(i); //the current cell in the row
        System.out.print("\t\t\t");


        switch (cell.getCellType()) {
            case STRING:
                System.out.print(cell.getStringCellValue());
                break;
            case NUMERIC:
                if(DateUtil.isCellDateFormatted(cell))
                    System.out.println(cell.getDateCellValue());
                System.out.print(cell.getNumericCellValue());
                break;
            case BOOLEAN:
                System.out.print(cell.getBooleanCellValue());
                break;
            case FORMULA:
                System.out.print(cell.getCellFormula());
                break;
            case ERROR:
                System.out.print(cell.getErrorCellValue());
                break;
            default:
                System.out.print("Unidentified Cell Value: " + cell.getCellType());
        }
    }
}

编辑：这是我当前的输出：我当前的输出

我希望它像第一列一样组织

谢谢。

标签： javaapache-poiprintf

解决方案

我解决了我需要创建一个方法的问题：

public void printSheetAsString(int sheetIndex){
    sheet = workbook.getSheetAt(sheetIndex);
    Row row;

    //a row iterator which iterates through rows in a specified sheet
    for(Iterator<Row> rowIterator = sheet.rowIterator(); rowIterator.hasNext();){
        row = rowIterator.next(); //store the next element into the variable "row"

        //a cell iterator which iterates through cells in the sheet's rows
        for(Iterator<Cell> cellIterator = row.cellIterator(); cellIterator.hasNext();){
            cell = cellIterator.next(); //store the next element into the variable "cell"
            cell.setCellType(CellType.STRING); //set all the cells to type string so that we can print them out easily

            //print "%" for place holder/variable, "-" for left justified table, "30" for spaces between each column, "s" for string
            //this will print the cell then move to the next cell, print that cell, so on, till we reach the next row, which repeats the process, them move to next row, and so on till rowIterator.hasNext() returns false
            System.out.printf("%-30s", cell.getStringCellValue());
        }

        System.out.println();
    }
}

重点在哪里：

//print "%" for place holder/variable, "-" for left justified table, "30" for spaces between each column, "s" for string
//this will print the cell then move to the next cell, print that cell, so on, till we reach the next row, which repeats the process, them move to next row, and so on till rowIterator.hasNext() returns false
System.out.printf("%-30s", cell.getStringCellValue());

这最终打印输出： 正确输出

然后我制作了另一种方法来正确打印变量，而不是将它们转换为字符串并使用不推荐使用的方法：

public void printSheet(int sheetIndex){
        sheet = workbook.getSheetAt(sheetIndex);
        Row row;

        for(Iterator<Row> rowIterator = sheet.rowIterator(); rowIterator.hasNext();){
            row = rowIterator.next();

            for(Iterator<Cell> cellIterator = row.cellIterator(); cellIterator.hasNext();){
                cell = cellIterator.next();

                switch (cell.getCellType()) {
                    case STRING:
                        System.out.printf("%-30s", cell.getStringCellValue());
                        break;
                    case NUMERIC:
                        if(DateUtil.isCellDateFormatted(cell))
                            System.out.printf("%-30s", cell.getDateCellValue().toString());
                        System.out.printf("%-30f", cell.getNumericCellValue());
                        break;
                    case BOOLEAN:
                        System.out.printf("%-30b", cell.getBooleanCellValue());
                        break;
                    case FORMULA:
                        System.out.printf("%-30s", cell.getCellFormula());
                        break;
                    case ERROR:
                        System.out.printf("%-30x", cell.getErrorCellValue());
                        break;
                    default:
                        System.err.print("[ERROR]: Unidentified Cell Value: " + cell.getCellType());
                }
            }

            System.out.println();
        }
    }
}

这也给出了相同的结果。

谢谢！

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