CSV在java中读取 [英] CSV reading in java

问题描述

我在从CSV档案读取时遇到问题

Im having trouble reading from a CSV file

final String DELIMITER = ",";
    Scanner fileScan = null;
    Scanner dataSetScan = null;
    String dataSet = null;
    String sql = "";
    File users = new File("user.txt");
    String nickname = "";
    String lastname = "";
    String firstname = "";
    String cartype = "";
    String personimage = "";
    String carimage = "";
    int user_id = 0;

    try {
        fileScan = new Scanner(users);
    } catch (Exception e) {
        System.out.println(e);
    }

while(fileScan.hasNext()){
        dataSet = fileScan.nextLine();
        dataSetScan = new Scanner(dataSet);
        dataSetScan.useDelimiter(DELIMITER);

        nickname = dataSetScan.next();
        lastname = dataSetScan.next();
        firstname = dataSetScan.next();
        cartype = dataSetScan.next();
        personimage = dataSetScan.next();
        carimage = dataSetScan.next();

        sql += "INSERT INTO users VALUES (";
        sql += user_id++ + ", ";
        sql += "'" + nickname + "', ";
        sql += "'" + lastname + "', ";
        sql += "'" + firstname + "', ";
        sql += "'" + cartype + "', ";
        sql += "'" + personimage + "', ";
        sql += "'" + carimage + "' ";
        sql += ");\n";

    }

上述代码不适用于示例文件

The above code wont work on the example file

alice,Wonder-Land,Alice,red Vauxhall Corsa,alice.jpg,alice_car.jpg
bob,Kett,Robert,,,
charlie,Carlos,Don,,,

在行尾有一个逗号。 （hvaing这里的逗号不是一个选项）

However, it works just fine when there is a comma at the end of the line. (hvaing a comma here is not an option)

我能做什么使这项工作？

What can i do to make this work? It must be to do with my delimeter i think

谢谢

推荐答案

p>您是否从以下行获得NoSuchElementException？

Are you getting a NoSuchElementException from the following line?

carimage = dataSetScan.next();

如果是这样，你只需要使用hasNext检查，

If so you just need to wrap that with a hasNext check and perform a null check when you build your string.

if(dataSetScanner.hasNext()){
    carimage = dataSetScan.next();
}
else{
    carimage =  null;
}

...

sql += carimage  == null ? "NULL" : "'" + carimage + "' ";

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