我的扫描仪正在使用分隔符读取文本文件。但是，当我运行程序时，唯一打印出来的行是第一行数据，然后我会抛出一个输入不匹配异常。我相信错误在于它没有移动到下一行。我了解不匹配是如何工作的，我只是不确定如何解决它。我试过把scanner.nextLine(); 正如您在下面的代码中看到的那样。
这是我的扫描仪代码：
/**
* Method for reading the data from the electricToolData.txt file.
*/
public void readElectricToolData()
{
Frame myFrame = null; // initialises frame to null
FileDialog fileBox = new FileDialog(myFrame,
"Open", FileDialog.LOAD);
fileBox.setVisible(true);
String directoryPath = fileBox.getDirectory();
String filename = fileBox.getFile();
System.out.println(filename + " " + directoryPath); // prints out name of file and directory path
try {
File dataFile = new File(filename);
Scanner scanner = new Scanner(dataFile);
while(scanner.hasNext())
{
String lineOfText = scanner.nextLine(); // reads the next line of the file and stores as String
//if statement checks if line starts with either "//" or space.
if (lineOfText.startsWith("//") || lineOfText.isEmpty())
{
}
else // now got real data
{
Scanner scanner2 = new Scanner(lineOfText);
scanner2.useDelimiter(",");
lineOfText.trim();
System.out.println(lineOfText);
while(scanner2.hasNext())
{
//lineOfText.trim();
boolean mRechargeable = scanner.nextBoolean();
String mPower = scanner.next();
String mToolName = scanner.next();
String mItemCode = scanner.next();
int mTimesBorrowed = scanner.nextInt();
boolean mOnLoan = scanner.nextBoolean();
int mCost = scanner.nextInt();
int mWeight = scanner.nextInt();
scanner.nextLine();
ElectricTool electricTool = new ElectricTool(mToolName, mItemCode, mTimesBorrowed, mCost, mWeight, mPower);
toolsList.add(electricTool);
}
}
//System.out.println(lineOfText); // prints out string
}
scanner.close();
scanner.close(); // closes scanner
}
catch(FileNotFoundException e)
{
System.err.println("Caught IOException: " + e.getMessage());
}
}
该错误显示在布尔值mRechargeable = Scanner.nextBoolean（）;处。
这是数据文件：
// this is a comment, any lines that start with //
// (and blank lines) should be ignored
// data is rechargeable, power, toolName, itemCode, timesBorrowed, onLoan, cost, weight
true,18V,Makita BHP452RFWX,RD2001,12,false,14995,1800
true,10.8V,Flex Impact Screwdriver FIS439,RD2834,14,true,13499,1200
false,1350W,DeWalt D23650-GB Circular Saw, RD6582,54,true,14997,5400
false,1500W,Milwaukee DD2-160XE Diamond Core Drill,RD4734,50,false,38894,9000
true,10.8V,Bosch GSR10.8-Li Drill Driver,RD3021,25,true,9995,820
false,900W,Bosch GSB19-2REA Percussion Drill,RD8654,85,false,19999,4567
true,10.8V,Flex Impact Screwdriver FIS439, RD2835,14,false,13499,1200
true,18V,DeWalt DW936 Circular Saw,RD4352,18,false,19999,3300
false,2100W,Sparky FK652 Wall Chaser,RD7625,15,false,29994,8400
问题在于 String.trim() 不像您认为的那样工作：它不会改变调用它的 String，而是返回一个有效地删除了空格的新 String。这会导致该行没有被修剪，并且上面有很多空格字符的“空白行”无法通过您的第一个扫描仪.nextBoolean() 调用进行解析。
所以，更新：
String lineOfText = scanner.nextLine(); // reads the next line of the file and stores as String
成为：
// read the next line of the file, removing enclosing whitespace
String lineOfText = scanner.nextLine().trim();
理想情况下，注释应该在行之前，因为它更易于阅读和格式化，并且更明显的是它是注释。同时删除多余的 lineofText.trim(); 稍后在代码中。
此外，请记住在完成后关闭所有 Scanner 实例（所以这里每行一个，文件一个）。
下一个问题是，在内部循环中，您构建 ElectricTool 实例，您调用的是扫描仪上的方法，而不是扫描仪 2（将其重命名为更具语义的内容，例如 itemScanner）：
Scanner itemScanner = new Scanner(lineOfText);
itemScanner.useDelimiter(",");
boolean mRechargeable = itemScanner.nextBoolean();
String mPower = itemScanner.next();
String mToolName = itemScanner.next();
String mItemCode = itemScanner.next();
int mTimesBorrowed = itemScanner.nextInt();
boolean mOnLoan = itemScanner.nextBoolean();
int mCost = itemScanner.nextInt();
int mWeight = itemScanner.nextInt();
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