解析 csv 文件處理空值 java

Question

我是 java 和練習解析 csv 文件的新手。 我已經弄清楚了如何解析和使用構造函數來創建實例。 但是，我的 csv 文件中有空字符串，控制台只是向我拋出IllegalArgumentException: No enum constant 。

我提到過：

1. 枚舉值 IllegalArgumentException：沒有枚舉常量 class
2. 解析 java 中的 CSV 文件，並用空值延遲

不幸的是，它不起作用。 當涉及到Person with empty Profession時，程序會中斷。 我是否需要填寫一些像“NONE”這樣的字符串來匹配枚舉，或者有什么方法可以解決這個問題？ 非常感謝任何幫助或提示。

以我的Profession為例：

public enum Profession {
    DOCTOR, CEO, CRIMINAL, HOMELESS, UNEMPLOYED, MUSICIAN, BOXER , UNKNOWN, NONE;
}

這是我的 csv 文件的樣子：

  [0],    [1], [2],    [3]  ,    [4]    ,   [5]   ,  [6] ,   [7]  ,  [8] , [9]
class, gender, age, bodyType, profession, pregnant, isYou ,species, isPet, role
scenario:green,   ,         ,           ,         ,        ,      ,      ,
person, female, 24, average ,           , FALSE   ,        ,      ,      , passenger
animal, male  ,  4,         ,           , FALSE   ,        , dog  , TRUE , pedestrian
  .
  .

下面是解析代碼：

try (BufferedReader csvReader = new BufferedReader(new FileReader(csvFile));) {
String headerLine = csvReader.readLine(); //get rid of header

while ((line = csvReader.readLine()) != null) { 
    csvContents.add(line);// add the line to the ArrayList      
}

for (String csvLine : csvContents) {

    // split by comma and remove redundant spaces
    String[] data = csvLine.split(",",-1); 
    System.out.println(data[1]);// IndexOutOfBound

    Character character = null;
    String clazz = data[0].toLowerCase();// cannot use word "class" as a variable


    if (clazz.startsWith("scenario"&& data.length == 1)) { 
        scenario = new Scenario();
        scenario.setLegalCrossing(clazz.endsWith("green"));
        continue;
    } else if ("person".equals(clazz)&& data.length == 10) {
        Profession professionEnum = Profession.valueOf(data[4].toUpperCase().trim());  
        Gender genderEnum = Gender.valueOf(data[1].toUpperCase().trim());
        BodyType bodyTypeEnum =BodyType.valueOf(data[3].toUpperCase().trim());

        person = new Person(Integer.parseInt(data[2]), professionEnum ,genderEnum , bodyTypeEnum , Boolean.parseBoolean(data[5]));
        person.setAsYou(Boolean.parseBoolean(data[6]));

    } else if ("animal".equals(clazz)) {
        Gender genderEnum = Gender.valueOf(data[1].toUpperCase().trim());
        BodyType bodyTypeEnum =BodyType.valueOf(data[3].toUpperCase().trim());

        animal = new Animal(Integer.parseInt(data[2]) , genderEnum , bodyTypeEnum, data[7]);
        animal.setIsPet(Boolean.parseBoolean(data[8]));
    }
} catch (someException e) {
  e.printStackTrace();
}

解析后的行看起來像：

scenario:green,,,,,,,,,
person,female,24,average,doctor,false,false,,,passenger
person,male,40,overweight,unknown,false,false,,,passenger
person,female,2,average,,false,false,,,passenger
person,male,82,average,,false,false,,,pedestrian
person,female,32,average,ceo,true,false,,,pedestrian
person,male,7,athletic,,false,false,,,pedestrian
animal,male,4,,,false,false,dog,true,pedestrian
scenario:red,,,,,,,,,

Answer 1

執行以下操作：

final int NO_OF_FIELDS = 10;
for (String csvLine : csvContents) {

    // split by comma and remove redundant spaces
    String[] data = csvLine.split(",", -1);
    if (data.length == NO_OF_FIELDS) {// <---Add this check to avoid ArrayIndexOutOfBoundsException
        System.out.println(data[1]);

        Character character = null;
        String clazz = data[0].trim().toLowerCase();// <---Trim to get rid of leading and trailing space

        if (clazz.startsWith("scenario" && data.length == 1)) {
            // ...
        } else if ("person".equals(clazz) && data.length == 10) {
            // Handle the exception as shown below
            Profession professionEnum;
            try {
                professionEnum = Profession.valueOf(data[4].trim().toUpperCase());// <---First trim then apply
                                                                                    // toUpperCase()
            } catch (IllegalArgumentException e) {
                professionEnum = Profession.UNKNOWN;
            }

            // ...

        } else if ("animal".equals(clazz)) {
            // ...
        }
    }
}