使用空间读取csv数据并使用java将其提取到数组中

Question

1. 我正在使用java程序读取csv文件（成功完成）

2. 我想提取二维数组中的所有数据（部分成功）

我面临的问题是，当某些单词有空格（例如“洛杉矶”、“新德里”）时，它会显示错误 -

我的employee.CSV 文件就像-

姓名、年龄、城市、国家、工资

约翰，25，洛杉矶，美国，30000

大卫，28，巴黎，法国，45000

李安妮，23，东京，日本，20000

Hemal,24,新德里,印度,40000

如果没有空格，例如。 LosAngeles ， NewDelhi ，然后它对我来说工作正常，但我需要只有空间的数据。（我想在 selenium 中使用填充数组）

我写的代码如下-

package java2package;
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class Datadriven {
public static void main(String[] args) {
String[][] myArray = new String[4][5];

    String[] tempArray=new String[5];
    int Rowc=0;
    String fileName="employee.csv";
    File file=new File(fileName);
try 
{

    Scanner content=new Scanner(file);
    content.next();
    while(content.hasNext())
    {
        String data=content.next();
        tempArray=data.split(",");

        for(int i=0;i<5;i++)
        {   
            myArray[Rowc][i]=tempArray[i];

        }

        Rowc++;
    }
    content.close();
    for(int i=0;i<4;i++){
    for(int j=0;j<5;j++){
    System.out.print(myArray[i][j]+" ");
    }
    System.out.print("\n");
    }

} catch (FileNotFoundException e)
{
    System.out.println(e);
}


    }

}

我正在使用 Eclipse，我得到的错误是 - 线程“main”中的异常 java.lang.ArrayIndexOutOfBoundsException: 3 at java2package.Datadriven.main(Datadriven.java:31)

Answer 1

通过使用next()，您只会阅读到下一个空白字符。由于您正在对数组长度进行硬编码，因此您会得到一个 ArrayIndexOutOfBoundsException，因为您最终得到的元素比您预期的要少。

使用hasNextLine() 和nextLine() 应该会产生您想要的结果。但无论如何，检查边界可能是个好主意，因为您使用的是外部数据。

Answer 2

您可以尝试使用 IO 缓冲区来读取数据，而不是扫描仪。下面的示例使用 MappedByteBuffer 遍历 csv 文件并将数据检索到数组中。

public class SO {
public static void main(String[] args) {
    String[][] myArray = new String[4][5]; //Your array
    Path file = Paths.get(System.getProperty("user.home")).resolve("Desktop").resolve("tester.csv"); //Path to file
    try {
        RandomAccessFile raf = new RandomAccessFile(file.toString(), "rw"); //Get file
        MappedByteBuffer mbuff = raf.getChannel().map(MapMode.READ_WRITE, 0L, Files.size(file)); //Create mapped buffer to file for bytes transfer

        mbuff.position(28); //  //Name,Age,City,Country,Salary = 28 bytes, so we will position buffer after start headings
        for(int i = 0; i < 4; i++){//For each array
            for(int j = 0; j < 5; j++){//For each element
                myArray[i][j] = getSegment(mbuff); //Get the next 'segment' which should be desired value
                System.out.print("\"" + myArray[i][j] + "\"" + " ");//Print array as proof of what it contains
            }
            System.out.println();
        }

    raf.close();
    } catch (IOException io) {
        io.printStackTrace();
    }
}

public static String getSegment(MappedByteBuffer mb){
    StringBuilder sb = new StringBuilder();//StringBuilder to hold segment
    while(mb.hasRemaining()){
        char c = (char)mb.get();//Each individual char
        if((c == '\n' || c == '\r') && sb.length() == 0){//Ignore newline unless their is value is Stringbuilder
            continue;
        } else if((c == '\n' || c == '\r')){//Newline and something is in the Stringbuilder
                break;//Break loop to return the 'segment'
        } else if(c != ','){ //Not a comma
            sb.append(c); //Append
        } else if(mb.position() == mb.capacity()){ //End of file
            break; //Break loop
        } else {
            break; //Break
        }
    }
    return sb.toString();//Return segment
}
}

祝你好运！

Answer 3

更好的是，使用 csv 库，例如 opencsv，示例如下：

CSV csv = CSV
    .separator(',')  // delimiter of fields
    .quote('"')      // quote character
    .create();       // new instance is immutable
csv.read("employee.CSV", new CSVReadProc() {
    public void procRow(int rowIndex, String... values) {
        System.out.println(rowIndex + ": " + Arrays.asList(values));
    }
});

如果您还有其他问题，请随时发表评论...

Answer 4

这是最简单的没有缺陷的模板，它还需要注意您的 CSV 是否将第一行作为标题。好的是它，如果你交换标题就不会失败。

最终这将返回一个Model 的数组。如果您愿意，您可以转换成二维字符串数组。 :)

看看这是否有帮助：

public class ReadCSV {

public static final String NAME = "Name";
public static final String AGE = "Age";
public static final String CITY = "City";
public static final String COUNTRY = "Country";
public static final String SALARY = "Salary";
public static String[] headers;

public static Model[] readData(String fileName) {
    BufferedReader reader = null;
    String line = null;
    List<Model> models = new ArrayList<Model>();
    String[] split = null;
    int index = 0;
    try {
        reader = new BufferedReader(new FileReader(fileName));
        while ((line = reader.readLine()) != null) {
            split = line.split(",");
            if (split != null && split.length > 0) {
                if (index > 0)
                    models.add(getModel(split));
                else {
                    headers = new String[split.length];
                    System.arraycopy(split, 0, headers, 0, split.length);
                }
            }
            index++;
        }

    }
    catch (FileNotFoundException e) {
    }
    catch (Exception e) {
    }
    finally {
        try {
            reader.close();
        }
        catch (Exception e) {
        }
    }

    return models.toArray(new Model[0]);

}

private static Model getModel(String[] split) {
    Model model = new Model();

    for (int i = 0; i < headers.length; i++) {
        try {
            if (headers[i] != null && headers[i].equalsIgnoreCase(NAME)) {
                model.setName(split[i]);

            }
            else if (headers[i] != null && headers[i].equalsIgnoreCase(COUNTRY)) {
                model.setCountry(split[i]);

            }
            else if (headers[i] != null && headers[i].equalsIgnoreCase(CITY)) {
                model.setCity(split[i]);

            }
            else if (headers[i] != null && headers[i].equalsIgnoreCase(AGE)) {
                model.setAge(convertInt(split[i]));

            }
            else if (headers[i] != null && headers[i].equalsIgnoreCase(SALARY)) {
                model.setSalary(convertDouble(split[i]));

            }
            else {

            }
        }

        catch (Exception e) {
        }
    }

    return model;
}

private static double convertDouble(String s) {
    double value = 0.0;
    try {
        value = Double.parseDouble(s);
    }
    catch (Exception e) {
    }
    return value;
}

private static int convertInt(String s) {
    int value = 0;
    try {
        value = Integer.parseInt(s);
    }
    catch (Exception e) {
    }
    return value;
}

}

class Model {
private String name;
private int age;
private String city;
private String country;
private double salary;

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public int getAge() {
    return age;
}

public void setAge(int age) {
    this.age = age;
}

public String getCity() {
    return city;
}

public void setCity(String city) {
    this.city = city;
}

public String getCountry() {
    return country;
}

public void setCountry(String country) {
    this.country = country;
}

public double getSalary() {
    return salary;
}

public void setSalary(double salary) {
    this.salary = salary;
}
}