Question

以下是我每行读取文本文件行的代码。

    ArrayList<Student> studentCollection = new ArrayList<Student>();
    BufferedReader in = null;
    try {
        in = new BufferedReader(new FileReader("StudentAnswers2.txt"));
        String read = null;
        while ((read = in.readLine()) != null) 
        {
            read = in.readLine();
            String[] splited = read.split(",");
            int[] answersTrans = new int[20]; 
            for(int i = 0; i < 20; i++)
            {
                answersTrans[i] = Integer.parseInt(splited[i+3]); 
            }           
            studentCollection.add(new Student(splited[0], splited[1], splited[2], answersTrans));                  
        }

上下文：我试图将每个逗号分隔值设置为学生列表对象的字段（每个学生一行）。前3个值需要作为String参数输入，后面的20个值作为一个int []数组进入。

这里是txt文件的内容：

C97288501，拜恩，约翰，0,3,3,0,2,4,0,1,4,5,0,3,3,1,2,4,2,0,4,5 D11255403，史密斯，艾琳，1,3,2,0,4,3,1,4,5,0,3,3,1,3,4,5,0,5,4,0 C06623662，多伊尔，玛丽，1,4,3,3,2,2,1,1,4,5,3,3,3,5,2,4,2,5,4,5 C02887223，Radecki，杰森，2,4,3,0,2,2,4,1,0,2,3,3,5,0,4,4,0,4,0,5 D11123581，汉利，诺拉，1,0,2,2,3,0,0,1,5,4,3,3,0,3,2,4,0,5,4,4

Answer 1

删除额外的in.readLine()，因为您已经在while循环的条件下读取了该行。额外in.readLine()会导致您跳过每隔一行，并可能导致以下read.split(",")抛出NullPointerException，因为您不会检查它是否返回null。

    while ((read = in.readLine()) != null) 
    {
        read = in.readLine(); // this extra readLine is wrong
                              // and should be removed

从文本文件读入时，为什么从read.split（“，”）方法获取NullPointerException？

1 个答案: