读取Java中的CSV文件

Question

I have a csv that I am trying to read into an array of objects. I keep getting the following error... java.util.InputMismatchException I think it is because its reading the file split by spaces and not by the commas. I believe I need to use the String.split() method, but I am not sure exactly how to do this. Any suggestions. Here is the code that I have thus far...

public class Prog7
{
public static void main(String[] args)
{
    Part[] parts;
    int numParts;
    int partNumber;
    String description;
    double price;
    int quantity;
    String city;

    parts = new Part[100];
    numParts = 0;

    Scanner inFile = null;

    /*
     * open file
     */
    try
    {
        inFile = new Scanner( new File( "C:/COSC 210/Assignment#7/parts.txt" ) );
    }
    catch ( FileNotFoundException e )
    {
        System.err.println( "Error: file not found" );
    }

    inFile.useDelimiter(",");
    while( inFile.hasNext() )
    {
        partNumber = inFile.nextInt();
        description = inFile.next();
        price = inFile.nextDouble();
        city = inFile.next();
        quantity = inFile.nextInt();

        Part p = new Part(partNumber, description, price, 
                  quantity, city);
        parts[numParts]= p;
        numParts++;
    }
    inFile.close();

    for (int i = 0; i < numParts; i++)
    {
        System.out.println(parts[i].getPartNumber());
    }
}
}

Answer 1

you need to read the data as String rather than int/double . After reading data as String parse it to int .

Answer 2

It would help if you paste the line of text that causes this failure. As you suspect, probably a space char precedes or succeeds the delimited comma. Just change the delimiter to

inFile.useDelimiter("\\s*,\\s*")

Answer 3

In your place I create separate bean class

public class MyNewBean {

    int numParts;
    int partNumber;
    String description;
    double price;
    int quantity;
    String city;

    //get, set
}

End then read about advantages of OpenCSV. If you use comma as delimenter what should you do with description which also can contain commas. Java bean based on the field positions in your CSV file

 CSVReader reader = new CSVReader(new FileReader("C:/COSC210/Assignment#7/parts.txt"));
ColumnPositionMappingStrategy strat = new ColumnPositionMappingStrategy(); 
strat.setType(MyNewBean.class); 
String[] columns = new String[] {"numParts", "partNumber", "description", "price",                  "quantity", "city"}; // the fields to bind do in your JavaBean 
strat.setColumnMapping(columns); 
CsvToBean csv = new CsvToBean(); 
List list = csv.parse(strat, yourReader);

Read more about OpenCSV