我想读取 Excel 并根据某些条件写入同一个 Excel。 例如
Empno Name Salary
1 jonh 2000
2 Sam 3000
3 Dean 7000
现在我的要求是
1)想要根据列名称读取数据，并获取该列下的所有数据
2)以同样的方式根据列名称说“名称”我想再添加一行数据 即向同一个 Excel 文件添加新行后，数据应采用以下方式
Empno Name Salary
1 jonh 2000
2 Sam 3000
3 Dean 7000
4 Smith 8000
如何使用 Apache POI 执行此操作。
谁能给我举个例子吗？我想读取/读取同一个 Excel，不想创建新的 Excel。
提前致谢。
最佳答案
您可以引用下面我的示例程序，它可能会对您有所帮助。
package com.sam.test.excel;
/**
* @author Saminathan
*
*/
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Map;
import java.util.Set;
import java.util.TreeMap;
import org.apache.poi.POIXMLProperties;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFFont;
import org.apache.poi.hssf.util.HSSFColor;
import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.CellStyle;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.xssf.usermodel.XSSFFont;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
/**
* Sample Java program to read and write Excel file in Java using Apache POI
*
*/
public class FinalFormattingExcelWriting {
@SuppressWarnings("resource")
public static void main(String[] args) throws IOException,
InvalidFormatException {
FinalFormattingExcelWriting exl = new FinalFormattingExcelWriting();
// adding student info into sheet
exl.print("Student", "1", "Student1", "abc", 50, 78, 56, 55, 46);
exl.print("Student", "2", "Student2", "def", 60, 54, 89, 66, 79);
exl.print("Student", "3", "Student3", "ghi", 7, 96, 75, 88, 19);
exl.print("Student", "4", "Student4", "jkl", 89, 15, 35, 44, 78);
exl.print("Student", "5", "Student5", "mno", 40, 49, 46, 77, 46);
exl.print("Student", "6", "Student6", "pqr", 56, 45, 57, 44, 44);
exl.print("Student", "7", "Student7", "stu", 78, 61, 99, 66, 88);
exl.print("Student", "8", "Student8", "vwx", 91, 39, 40, 22, 38);
exl.print("Student", "9", "Student9", "yz", 45, 78, 49, 77, 59);
exl.print("Student", "10", "Student10", "abc1", 77, 65, 77, 95, 46);
System.out.println("Task Completed........................");
}
/*
* Existing sheet and new sheet adding process
*/
@SuppressWarnings("resource")
public void print(String excelSheetName, String dataForRollNo,
String dataForName, String dataForDept, int dataForSubj1,
int dataForSubj2, int dataForSubj3, int dataForSubj4,
int dataForSubj5) throws IOException {
XSSFWorkbook workbook = null;
File file = new File("D:/workspace/ex/examples/src/Student_Sheet.xlsx");
FileOutputStream out = null;
XSSFSheet excelSheet = null;
CellStyle style = null;
XSSFFont font = null;
Map<String, Object[]> excelData = new TreeMap<String, Object[]>();
// verifying file is present or not
if (file.exists()) {
FileInputStream inputStream = new FileInputStream(file);
workbook = new XSSFWorkbook(inputStream);
// verifying the sheet is available or not
if (workbook.getSheet(excelSheetName) != null) {
excelSheet = workbook.getSheet(excelSheetName);
} else {
excelSheet = workbook.createSheet(excelSheetName);
// Style details for heading in new sheet
style = workbook.createCellStyle();
style.setFillForegroundColor(HSSFColor.GREEN.index);
style.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
font = workbook.createFont();
font.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);
font.setColor(HSSFColor.WHITE.index);
style.setFont(font);
excelData.put("0", new Object[] { "RollNo", "Name", "Dept",
"Subj1", "Subj2", "Subj3", "Subj4", "Subj5", "Total",
"Avg", "Result" });
addIntoCell(excelData, excelSheet, "0", style);
}
} else {
workbook = new XSSFWorkbook();
if (workbook.getSheet(excelSheetName) != null) {
excelSheet = workbook.getSheet(excelSheetName);
} else {
excelSheet = workbook.createSheet(excelSheetName);
// Style details for heading in new sheet
style = workbook.createCellStyle();
style.setFillForegroundColor(HSSFColor.GREEN.index);
style.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
font = workbook.createFont();
font.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);
font.setColor(HSSFColor.WHITE.index);
style.setFont(font);
excelData.put("0", new Object[] { "RollNo", "Name", "Dept",
"Subj1", "Subj2", "Subj3", "Subj4", "Subj5", "Total",
"Avg", "Pass/Fail" });
addIntoCell(excelData, excelSheet, "0", style);
}
}
// adding author name in excel sheet
POIXMLProperties xmlProps = workbook.getProperties();
POIXMLProperties.CoreProperties coreProps = xmlProps
.getCoreProperties();
coreProps.setCreator("Saminathan");
// This data needs to be written (Object[])
// Data calculation
int dataForTotal = dataForSubj1 + dataForSubj2 + dataForSubj3
+ dataForSubj4 + dataForSubj5;
double dataForAvg = dataForTotal / 5;
String dataForResult = "Fail";
if (dataForAvg > 55) {
dataForResult = "Pass";
}
excelData.put(dataForRollNo,
new Object[] { dataForRollNo, dataForName, dataForDept,
dataForSubj1, dataForSubj2, dataForSubj3, dataForSubj4,
dataForSubj5, dataForTotal,
Double.toString(dataForAvg), dataForResult });
addIntoCell(excelData, excelSheet, dataForRollNo, style);
try {
// Write the workbook in file system
out = new FileOutputStream(file);
workbook.write(out);
workbook.close();
out.close();
} catch (Exception e) {
e.printStackTrace();
}
}
// Inserting values into cell
public void addIntoCell(Map<String, Object[]> data, XSSFSheet sheet,
String excelID, CellStyle style) {
Set<String> keyset = data.keySet();
Cell cell = null;
Row row = null;
Object[] objArr = null;
int rownum = 0;
if (Integer.parseInt(excelID) >= 1) {
rownum = Integer.parseInt(excelID);
}
for (String key : keyset) {
row = sheet.createRow(rownum);
objArr = data.get(key);
int cellnum = 0;
for (Object obj : objArr) {
cell = row.createCell(cellnum++);
if (obj instanceof String) {
cell.setCellValue((String) obj);
} else if (obj instanceof Integer) {
cell.setCellValue((Integer) obj);
}
// applying style only for heading
if (Integer.parseInt(excelID) < 1) {
cell.setCellStyle(style);
}
}
}
}
}
输出将类似于
祝你好运...!!! :)
关于java - 使用 Apache POI 读取/写入同一 Excel 文件，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/18863166/