java csv文件中用逗号分隔的字符串

Question

这似乎是一个很容易解决的问题，但我一直坚持下去。任何人都可以帮助我并解释我在哪里做错了吗？ 我读了一个 csv 文件：

Time,Activ,Switch,A,B,C,D,E
5:58,on,,,,,,
6:00,on 123,,,ab cd,,,
6:02,on - off,1->2,6,ab cd,1,,
6:04,on,,,cd ab,1,,
6:06,off,,,,,,
7:22,on / off,,,,,,
7:30,on / of,3->4,15,,,,
7:34,home on,,,ab cd,,,

我想只用逗号分隔一行中的数据并保存到看起来像的数组中（第一行省略）：

1---> ["5:58","on", "", "", "", "", "", ""]
2---> ["6:00", "on 123", "", "", "ab cd", "", "", ""]
3---> ["6:02", "on - off", "1->2", "6", "ab cd", "1", "", ""]
6---> ["7:22", "on / off", "3->4", "15", "", "", "", ""]

等等......但我收到的数组也被空格和其他字符分割字符串

1---> ["5:58","on", "", "", "", "", "", ""]
2---> ["6:00", "on", "123", "", "", "ab", "cd", "", "", ""]
3---> ["6:02", "on", "-", "off", "1->2", "6", "ab", "cd", "1", "", ""]
6---> ["7:22", "on", "/", "off", "3->4", "15", "", "", "", ""]

这是我的代码：

public class Test {
    public static void main(String []args) {

    String fileName = "TestData.csv";
    File file = new File(fileName);

    try{
        Scanner inputStream = new Scanner(file);
        String firstLine = inputStream.next();
            while(inputStream.hasNext()){
                String dataRow = inputStream.next();

                String[] valuesInDataRow = dataRow.split(",",-1);

                for(int i=0;i<valuesInDataRow.length;i++){
                    System.out.println("---> " + valuesInDataRow[i]);
                }

            }
            inputStream.close();
        }
        catch(FileNotFoundException e) {
            e.printStackTrace();
        }

    }
}

我会非常感谢任何解释:)

Answer 1

您应该使用inputStream.nextLine() 而不是inputStream.next()

试试类似的东西

 public static void main(String[] args) {
        String fileName = "TestData.csv";
        File file = new File(fileName);

        try{
            Scanner inputStream = new Scanner(file);
            String firstLine = inputStream.nextLine();
            while(inputStream.hasNext()){
                String dataRow = inputStream.nextLine();

                String[] valuesInDataRow = dataRow.split(",",-1);

                for(int i=0;i<valuesInDataRow.length;i++){
                    System.out.println("---> " + valuesInDataRow[i]);
                }

            }
            inputStream.close();
        }
        catch(FileNotFoundException e) {
            e.printStackTrace();
        }
    }

Answer 2

在这里，我使用 Scanner.nextLine() 和 regx \\s*,\\s* 删除不需要的空白。

public class Test {
    public static void main(String []args) {

        String fileName = "TestData.csv";
        File file = new File(fileName);

        try{
            Scanner inputStream = new Scanner(file);
            String firstLine = inputStream.nextLine();
            while(inputStream.hasNext()){
                String dataRow = inputStream.nextLine();

                String[] valuesInDataRow = dataRow.split("\\s*,\\s*", -1);

                for(int i=0;i<valuesInDataRow.length;i++){
                    System.out.println("---> " + valuesInDataRow[i]);
                }

            }
            inputStream.close();
        }
        catch(FileNotFoundException e) {
            e.printStackTrace();
        }

    }
}

Answer 3

作为附加提示，我认为，使用 Java 1.7 功能“try-for-resource”将是一个很好的建议

https://www.journaldev.com/592/java-try-with-resources

代替：

try{
   Scanner inputStream = new Scanner(file);
   ...
   inputStream.close();
}
catch(FileNotFoundException e) {
  ...
}

总是更好用：

try(Scanner inputStream = new Scanner(file)) {
...
}
catch (IOException e) {
...
}

特别是如果文件很大。但是适用于 Java 1.7。