java excel转yaml追加到yaml文件下

要将Excel数据转换为YAML格式并附加到现有的YAML文件中，您可以按照以下步骤进行操作：

1. 读取Excel文件并将其转换为Java对象。

2. 使用Jackson库将Java对象转换为YAML字符串。

3. 打开现有的YAML文件并将其读取为字符串。

4. 将新的YAML字符串附加到现有的YAML字符串。

5. 将附加后的YAML字符串写回到现有的YAML文件中。

下面是一个示例代码，可以帮助您实现这个过程：

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.List;
import java.util.Map;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.dataformat.yaml.YAMLMapper;

import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

public class ExcelToYamlAppender {

    public static void main(String[] args) {

        // Step 1: Read Excel file and convert to Java object
        List<Map<String, String>> excelData = readExcelFile("input.xlsx");

        // Step 2: Convert Java object to YAML string
        String yamlData = convertToYaml(excelData);

        // Step 3: Read existing YAML file as string
        String existingYaml = readYamlFile("existing.yaml");

        // Step 4: Append new YAML data to existing YAML data
        String appendedYaml = existingYaml + yamlData;

        // Step 5: Write appended YAML data back to YAML file
        writeYamlFile("existing.yaml", appendedYaml);

    }

    private static List<Map<String, String>> readExcelFile(String filePath) {

        List<Map<String, String>> excelData = null;

        try (Workbook workbook = new XSSFWorkbook(new File(filePath))) {

            Sheet sheet = workbook.getSheetAt(0);

            for (int i = 1; i <= sheet.getLastRowNum(); i++) {

                Row row = sheet.getRow(i);

                if (row != null) {

                    String key = row.getCell(0).getStringCellValue();
                    String value = row.getCell(1).getStringCellValue();

                    // Create Java object with key-value pairs
                    Map<String, String> data = Map.of(key, value);

                    excelData.add(data);
                }
            }

        } catch (IOException e) {
            e.printStackTrace();
        }

        return excelData;
    }

    private static String convertToYaml(List<Map<String, String>> data) {

        String yaml = null;

        try {

            ObjectMapper objectMapper = new ObjectMapper(new YAMLMapper());
            yaml = objectMapper.writeValueAsString(data);

        } catch (IOException e) {
            e.printStackTrace();
        }

        return yaml;
    }

    private static String readYamlFile(String filePath) {

        String yamlData = null;

        try {

            yamlData = new String(Files.readAllBytes(Paths.get(filePath)));

        } catch (IOException e) {
            e.printStackTrace();
        }

        return yamlData;
    }

    private static void writeYamlFile(String filePath, String yamlData) {

        try (FileWriter fileWriter = new FileWriter(new File(filePath))) {

            fileWriter.write(yamlData);

        } catch (IOException e) {
            e.printStackTrace();
        }
    }

}

请注意，此示例代码仅供参考，并且可能需要根据您的特定需求进行修改和调整。