java - 如何将 java.io.File 转换或转换为 java.io.List？

Question

这就是我到目前为止所拥有的......

List<Point> points = new ArrayList<Point>();
Scanner input = new Scanner(System.in);
System.out.println("Enter the name of your file (fileName.dat):");
String fileName = input.nextLine();
points = (List<Point>)new File(fileName);

我想将文件转换或转换为列表。这是我从 NetBeans 收到的错误消息: 线程“main”中的异常java.lang.ClassCastException:java.io.File无法在closestpoints.ClosestPoints.main(ClosestPoints.java:185)处转换为java.util.List

Answer 1

您无法将文件转换为列表，但您可以读取文件的内容并将其解析为列表。考虑 Alvin Alexander 的示例代码 http://alvinalexander.com/blog/post/java/how-open-read-file-java-string-array-list :

/**
 *
 Open and read a file, and return the lines in the file as a list
 * of Strings.
 * (Demonstrates Java FileReader, BufferedReader, and Java5.)
 */
private List<String> readFile(String filename)
{
  List<String> records = new ArrayList<String>();
  try
  {
    BufferedReader reader = new BufferedReader(new FileReader(filename));
    String line;
    while ((line = reader.readLine()) != null)
    {
      records.add(line);
    }
    reader.close();
    return records;
  }
  catch (Exception e)
  {
    System.err.format("Exception occurred trying to read '%s'.", filename);
    e.printStackTrace();
    return null;
  }
}