為什么我的方法只能讀取一行文本？

Question

我有一種方法可以讀取文本文件的一部分，該文件有4個部分：日期，名稱，描述和金額，例如

4/5/2018, gel, hair product, 20.00
4/4/2018, wax, hair product, 20.00

等等...

我的問題是我的方法只會讀取第一行，然后輸出我的catch方法，說找不到該文件。

public static void showRecordedExpense(String filename)throws IOException {
    String date = "";
    String name = "";
    String description = "";
    double amount = 0.00;
     try{
         Scanner read = new Scanner(new File(filename));
         while (read.hasNextLine()){
             String oneLine = read.nextLine();
             String[] parts = oneLine.split(",");
             try {
                 date = parts[0];
                 name = parts[1];
                 description = parts[2];
                 amount = Double.parseDouble(parts[3]);
                 System.out.printf("%15s%15s%15s%20s%n", "---------------", "---------------",
                         "---------------", "---------------------");
                 System.out.printf("%15s%15s%15s%31s%n","Date", "Name", "Description","Amount");
                 System.out.printf("%15s%14s%33s%15s%n",date,name,description,amount);
                 System.out.printf("%15s%15s%15s%20s%n", "---------------", "---------------",
                         "---------------", "---------------------");
             }catch (Exception e){
                 System.out.println("no");
             } finally {
                 read.close();
             }
         }
     }catch (Exception e){
         System.out.println("The file could not be found");
     }

}

編輯：取出最后的工作。

Answer 1

在這里閱讀有關finally工作原理的詳細信息。 由於您finally與try/catch配對，因此您目前正在while循環的第一次迭代結束時關閉Scanner。 自關閉文件以來， while的下一次迭代無法再從文件中讀取，這就是為什么它僅讀取第一行的原因。 考慮在while循環完成后取出finally並僅關閉掃描儀。

     try{
         Scanner read = new Scanner(new File(filename));
         while (read.hasNextLine()){
             String oneLine = read.nextLine();
             String[] parts = oneLine.split(",");
             try {
                 date = parts[0];
                 name = parts[1];
                 description = parts[2];
                 amount = Double.parseDouble(parts[3]);
                 System.out.printf("%15s%15s%15s%20s%n", "---------------", "---------------",
                         "---------------", "---------------------");
                 System.out.printf("%15s%15s%15s%31s%n","Date", "Name", "Description","Amount");
                 System.out.printf("%15s%14s%33s%15s%n",date,name,description,amount);
                 System.out.printf("%15s%15s%15s%20s%n", "---------------", "---------------",
                         "---------------", "---------------------");
             }catch (Exception e){
                 System.out.println("no");
             }
         }

         read.close();
     }catch (Exception e){
         System.out.println("The file could not be found");
     }