Java POI读取excel

一、背景

有一个excel文件(.xlsx)，内容是这样的。

现在需要将它解析成{"小兰":20,"小黄":10}这样的json格式写入到一个txt文本文件中。

二、步骤

1.创建springboot项目，引入依赖。

        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi</artifactId>
            <version>5.0.0</version>
        </dependency>

        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-ooxml</artifactId>
            <version>5.0.0</version>
        </dependency>

        <dependency>
            <groupId>commons-io</groupId>
            <artifactId>commons-io</artifactId>
            <version>2.8.0</version>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.75</version>
        </dependency>

2.代码

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.nio.charset.Charset;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.io.IOUtils;
import org.apache.poi.ss.usermodel.CellType;
import org.apache.poi.xssf.usermodel.XSSFCell;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

import com.alibaba.fastjson.JSON;

public class Test {
    public static void main(String[] args) throws Exception {
        Map<String, Long> map = new HashMap<>();
        XSSFWorkbook workbook = new XSSFWorkbook(new FileInputStream("1.xlsx"));
        XSSFSheet sheet = workbook.getSheetAt(0);
        for (int i = 0; i < sheet.getLastRowNum() + 1; i++) {
            XSSFRow row = sheet.getRow(i);
            if (row != null) {
                Object o1 = getValue(row.getCell(0));
                Object o2 = getValue(row.getCell(1));
                if (o1 != null) {
                    String s1 = o1.toString().trim();
                    Long num1 = Long.parseLong(o2.toString().trim());
                    map.put(s1, num1);
                }
            }
        }
        IOUtils.write(JSON.toJSONString(map), new FileOutputStream("1.txt"), Charset
                .defaultCharset());
    }

    public static Object getValue(XSSFCell cell) {
        if (cell == null) {
            return null;
        }
        if (cell.getCellType() == CellType.STRING) {
            return cell.getStringCellValue();
        }
        if (cell.getCellType() == CellType.NUMERIC) {
            return (long)cell.getNumericCellValue();
        }
        return null;
    }
}