Programming - Teach you step by step how to read student information from Excel files

In today's information age, computer technology has penetrated into various fields, and programming has become one of the key technologies to promote information construction. Among many fields, student information management system is undoubtedly one of the important applications. This article will start from the development of student information management system and discuss how to complete the development efficiently and ensure quality.

Suppose there is a student information management system that needs to read students' names, ages, grades and other data from Excel files, and store these data in the system for further processing and management.

Specifically, by calling this function in the data import/export system and passing in the Excel file as a parameter, you can get results containing student information. This result can then be further processed, such as storing student data into a database or performing other business logic operations.

Different customized data processing demand scenarios may have subtle differences in details, and it would be too cumbersome to write it from scratch. At this time:

1 ) Think about the general needs and ask FuncGPT

For example, input requirements:

Read EXCEL data, input parameter: File file, output parameter: List<Map<String, Object>>

Get the complete code.

// Class name: ExcelDataReader

// Function name: readExcelData

// Function: Read Excel data and return results of type List<Map<String, Object>>

// POM dependency package:

// <dependency>

// <groupId>org.apache.poi</groupId>

// <artifactId>poi</artifactId>

// <version>4.1.2</version>

// </dependency>

// <dependency>

// <groupId>org.apache.poi</groupId>

// <artifactId>poi-ooxml</artifactId>

// <version>4.1.2</version>

// </dependency>

import org.apache.poi.ss.usermodel.*;

import java.io.File;

import java.io.FileInputStream;

import java.io.IOException;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

public class ExcelDataReader {

/**

* Read Excel data and return results of type List<Map<String, Object>>

* @param file Excel file

* @return List<Map<String, Object>> result of Excel data

* @throws IOException throws IOException when an error occurs while reading the Excel file

public static List<Map<String, Object>> readExcelData(File file) throws IOException {

List<Map<String, Object>> dataList = new ArrayList<>(); // Create a List to store Excel data

FileInputStream fis = new FileInputStream(file); // Create a file input stream

Workbook workbook = WorkbookFactory.create(fis); // Create Workbook object

Sheet sheet = workbook.getSheetAt(0); // Get the first Sheet

int rowCount = sheet.getLastRowNum(); // Get the number of rows

Row headerRow = sheet.getRow(0); // Get the header row

int columnCount = headerRow.getLastCellNum(); // Get the number of columns

for (int i = 1; i <= rowCount; i++) { // Traverse each row (skip the header row)

Row row = sheet.getRow(i);

Map<String, Object> rowData = new HashMap<>();

for (int j = 0; j < columnCount; j++) { // Traverse each column

Cell cell = row.getCell(j);

String columnName = headerRow.getCell(j).getStringCellValue(); // Get the column name

Object cellValue;

switch (cell.getCellType()) { // Get cell value based on cell type

case STRING:

cellValue = cell.getStringCellValue();

break;

case NUMERIC:

cellValue = cell.getNumericCellValue();

break;

case BOOLEAN:

cellValue = cell.getBooleanCellValue();

break;

case FORMULA:

cellValue = cell.getCellFormula();

break;

default:

cellValue = null;

}

rowData.put(columnName, cellValue); // Save column name and cell value into rowData

}

dataList.add(rowData); // Save rowData into dataList

}

workbook.close(); // Close the Workbook object

fis.close(); // Close the file input stream

return dataList; // Return the results of Excel data

}

// function example

// Example of reading Excel data

// Input parameters: file, Excel file

// Output parameters: dataList, List<Map<String, Object>> result of Excel data

// Call example:

// File file = new File("data.xlsx");

// List<Map<String, Object>> dataList = ExcelDataReader.readExcelData(file);

// System.out.println(dataList);

// Output results: For example, the Excel data is:

// | Name | Age | Grade |

// |-------|-----|-------|

// | Alice | 18 | A |

// | Bob | 20 | B |

// The output result is: [{Name=Alice, Age=18, Grade=A}, {Name=Bob, Age=20, Grade=B}]

// Indicates that the Excel data is encapsulated in the format of List<Map<String, Object>>

2 ) Modify according to the code of FuncGPT

Since the overall format content of EXCEL will affect reading the real data of valid rows or columns, it is necessary to perform relevant valid verification on rows and columns. Based on the original code, make some modifications:

① First determine the column, because the actual length of the column will affect the reading of the row;

② Read the header of the first row. If a blank column is encountered, the valid column is determined to be the subscript of the previous column.

③After obtaining the valid columns, traverse each row of data. If there is an entire row of data, jump out of the loop and end the data acquisition.

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Programming - Teach you step by step how to read student information from Excel files

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