如何从系统外部的Java代码读取Excel文件？

Question

我正在使用Java（Eclipse）读取Excel文件的内容并将其存储在行对象列表中。 要读取文件，我已在代码中指定了文件路径。 在这种情况下，它类似于D：/Refreshed_data_daily/all_hue_posts_in_excel.xlsx。 如果代码存在于其他位置（即，在其他系统中），该路径不必相同。 我该如何处理这种情况？

公共类FacebookDataList {

private static final String FILE_NAME="D:/Refreshed_data_daily/all_hue_posts_in_excel.xlsx";
private static final String SHEET_NAME="nextv54plus_actions";
XSSFWorkbook workbook;

public static void main(String[] args){

    FacebookDataList obj= new FacebookDataList();
    List<FacebookFields> displayList= new ArrayList<FacebookFields>();
    displayList=obj.getTheDataIntoList();
    System.out.println("The Size of the list is:"+ displayList.size());
}

public List<FacebookFields> getTheDataIntoList() {
    List<FacebookFields> fbList= new ArrayList<FacebookFields>();
    try
    {
        FileInputStream fin= new FileInputStream(FILE_NAME);
        workbook= new XSSFWorkbook(fin);
        int sheetIndex=0;
        for (Sheet sheet : workbook) {
            readSheet(sheet,sheetIndex ++, fbList);}

    }catch(FileNotFoundException e){
        e.printStackTrace();
    }
    catch(IOException e){
        e.printStackTrace();
    }
    return fbList;
}

private void readSheet(Sheet sheet, int sheetIndex , List<FacebookFields> fbList) {

    if(SHEET_NAME.equals(sheet.getSheetName())){
        workbook.removeSheetAt(sheetIndex);
        return;
    }
    for (Row row : sheet){
        if (row.getRowNum() > 0)
            fbList.add(readRow(row));}

}

private FacebookFields readRow(Row row) {

    FacebookFields record= new FacebookFields();
    for (Cell cell : row) {
        switch (cell.getColumnIndex()) {
        case 0: record.setName(cell.getStringCellValue()); 
        break; 
        case 1: record.setId(cell.getStringCellValue()); 
        break; 
        case 2: record.setDate(cell.getStringCellValue());
        break; 
        case 3: record.setMessage(cell.getStringCellValue());
        break; 
        case 4: record.setType(cell.getStringCellValue());
        break; 
        case 5: record.setPage(cell.getStringCellValue());
        break; 
        case 6: record.setLikeCount(String.valueOf(cell.getNumericCellValue()));
        break; 
        case 7: record.setCommentCount(String.valueOf(cell.getNumericCellValue())); 
        break; 
        case 8: record.setShareCount(String.valueOf(cell.getNumericCellValue())); 
        break; 
        }
    }

    return record;
}

public boolean checkIfListContainsData() {

    List<FacebookFields> checkList= getTheDataIntoList();   
    return !checkList.isEmpty() ;
}

}

Answer 1

您可以让用户从头开始输入位置。 或者，将其伸到应有的位置，如果文件不存在，则将错误返回给用户。

Answer 2

将其添加到配置文件。 我为配置文件对象编写了以下类。 配置应位于运行路径中名为config.properties的文件内。

https://github.com/achinthagunasekara/JavaConfigFileReader

这样的事情对于存储应用程序配置非常有效。

配置文件

ConfigItem1=ItemValue1
.
.
.
ConfigItemN=ItemValueN

Java类

package Config;

import java.io.FileInputStream;
import java.io.IOException;
import java.util.Properties;

/**
 *
 * @author Achintha Gunasekara
 * @date 07.09.2015
 */

public class ConfigFileReader {

    //Configuration file used by the config reader
    //config file must be located inside the application path
    private final String file = "config.properties";
    private Properties properties;
    private static ConfigFileReader instance;

    public static ConfigFileReader getConfigFileReaderInstance() throws IOException {

        //there can only be once instance of the config reader
        if(instance == null) {

            instance = new ConfigFileReader();
        }

        return instance;
    }

    private ConfigFileReader() throws IOException {

        loadConfig(file);
    }

    //read and load the config file
    private void loadConfig(String configFile) throws IOException {

        properties = new Properties();
        properties.load(new FileInputStream(configFile));
    }

    //reloads the configuration during runtime
    public void reloadConfig() throws IOException {

        loadConfig(file);
    }

    //reloads the configuration during runtime from a provided configuration file
    public void reloadConfig(String configFile) throws IOException {

        loadConfig(configFile);
    }

    //get the propery value for strng s
    public String getPropertyFor(String configItem) throws Exception {

        String value = properties.getProperty(configItem);

        if(value == null) {

            throw new Exception(configItem + " not found!");
        }

        return value;
    }
    //returns int property
    public Integer getIntPropertyFor(String configItem) throws Exception {

        return Integer.parseInt(getPropertyFor(configItem));
    }

    //returns double property
    public Double getDoublePropertyFor(String configItem) throws Exception {

        return Double.parseDouble(getPropertyFor(configItem));
    }

    //returns bool property
    public Boolean getBooleanPropertyFor(String s) throws Exception {

        return Boolean.parseBoolean(getPropertyFor(s));
    }
}

Answer 3

此处定义的字符串数组参数

public static void main(String[] args)

包含在执行类时传递的命令行参数，或者可以在Eclipse运行配置中传递。

将功能更改为

public List<FacebookFields> getTheDataIntoList(String filePath)

并在初始化文件输入流时使用filePath