updateEmployees(PersonnelManager pm) 方法读取一个文本文件，并根据文件中每行的第一个字符（有 3 种可能性）执行不同的代码。PersonnelManager 和 Employee 类在问题中没有任何作用，这就是为什么我没有将它们包括在这里。这是一个示例输入文件：
n Mezalira, 卢卡斯 h 40000
r 5
d 金赛
n Pryce, Lane s 50
r 4
这是方法：（文件和扫描器对象在方法之外声明）
public static boolean updateEmployees(PersonnelManager pm) {
try
{
file = new File(updates);
in = new Scanner(file);
}
catch (FileNotFoundException e)
{
System.out.println("Could not load update file.");
return false;
}
int currentLine = 1; //Keep track of current line being read for error reporting purpose
while (in.hasNext()) {
String line = in.nextLine();
//Check the type of update the line executes
//Update: Add new Employee
if (line.charAt(0) == 'n') {
String[] words = line.split("\\s"); //Split line into words. Index [0]: update type. [1]: last name. [2]: first name. [3]: employee type. [4]: wage.
words[1] = words[1].substring(0, words[1].length() - 1); //remove comma from last name
if (words.length != 5) { //If there are not 5 words or tokens in the line, input is incorrect.
System.out.println("Could not update. File contains incorrect input at line: " + currentLine);
return false;
}
if (words[3].equals("s")) //if employee is type SalariedEmployee
pm.addEmployee(new SalariedEmployee(words[2], words[1], Double.parseDouble(words[4])));
else if (words[3].equals("h")) //if employee is type HourlyEmployee
pm.addEmployee(new HourlyEmployee(words[2], words[1], Double.parseDouble(words[4])));
else {
System.out.println("Could not update. File contains incorrect input at line: " + currentLine);
return false;
}
//Display information on the console
System.out.println("New Employee added: " + words[1] + ", " + words[2]);
}
//Update: Raise rate of pay
if (line.charAt(0) == 'r') {
String[] words = line.split("\\s"); //Split line into words. Index [0]: update type. [1]: rate of wage raise
if (Double.parseDouble(words[1]) > 100.0) { //If update value is greater than 100
System.out.println("Error in line:" + currentLine + ". Wage raise rate invalid.");
return false;
}
for (int i =0; i<pm.howMany(); i++) { //Call raiseWages() method for all employees handled by the pm PersonnelManager
pm.getEmployee(i).raiseWages(Double.parseDouble(words[1]));
}
//Display information on the console
System.out.println("New Wages:");
pm.displayEmployees();
}
//Update: Dismissal of Employee
if (line.charAt(0) == 'd') {
String[] words = line.split("\\s"); //Split line into words. Index [0]: update type. [1]: last name of employee
if (words.length != 2) { //If there are not 2 words or tokens in the line, input is incorrect.
System.out.println("Could not update. File contains incorrect input at line: " + currentLine);
return false;
}
String fullName = pm.getEmployee(words[1]).getName(); //Get complete name of Employee from last name
pm.removeEmployee(words[1]);
//Display information on the console
System.out.println("Deleted Employee: " + fullName);
}
currentLine++;
}
return true;
}
由于输入文件中有 5 行，while 循环应该执行 5 次，但事实并非如此。当它到达输入文件中的第 4 行：“n Pryce, Lane s 50”时，在代码的第 25 行出现“java.lang.StringIndexOutOfBoundsException”错误。
问题出现在第 24 和 25 行：
String[] words = line.split("\\s"); //Split line into words. Index [0]: update type. [1]: last name. [2]: first name. [3]: employee type. [4]: wage.
words[1] = words[1].substring(0, words[1].length() - 1); //remove comma from last name
对于输入的第 4 行，“line”字符串没有按照应有的方式分成 5 个字符串。它只被拆分为一个，在 words[0] 中，它等于“n”。我不明白的是程序使用同一行代码来拆分前 3 行输入的字符串，为什么它在第 4 行不起作用？
当我将输入文件更改为
n Mezalira, 卢卡斯 h 40000
r 5
d 金赛
删除命令“n”的第二次出现，它可以工作。事实上，每次我多次使用使用相同命令（“n”、“r”或“d”）的输入文件时，第二次出现该命令的行只会被拆分为 1 个字符串。包含行上的第一个标记（在这种情况下为“n”、“r”或“d”）。
我希望我的解释很清楚。如果有人知道为什么会这样，请帮忙。