找不到符号 -- 符号：方法 lastIndexOf(java.lang.String) 位置：类 java.util.Scanner
我的代码尝试提取文件名以通过读取包含该文件名的另一个文件来加载文件：
public static void main(String[] args) throws IOException
{
Scanner scan;
String transFilename;
String filename;
scan = new Scanner(System.in);
System.out.print("Enter the name of your transaction file please (include .txt extension): ");
transFilename = scan.nextLine();
scan = new Scanner(new FileReader(transFilename));
filename = readLine.next(2,readLine.lastIndexOf(""));
Scanner input = new Scanner( new FileReader(filename));
}
生成的错误：
blah.java:72: cannot find symbol
symbol : method lastIndexOf(java.lang.String)
location: class java.util.Scanner
filename = readLine.next(2,readLine.lastIndexOf(""));
^
1 error
当我尝试使用应内置于 java 中的“.length”方法时，会生成相同的错误...
My code tries to extract a filename to load a file from reading another file that contains the filename:
public static void main(String[] args) throws IOException
{
Scanner scan;
String transFilename;
String filename;
scan = new Scanner(System.in);
System.out.print("Enter the name of your transaction file please (include .txt extension): ");
transFilename = scan.nextLine();
scan = new Scanner(new FileReader(transFilename));
filename = readLine.next(2,readLine.lastIndexOf(""));
Scanner input = new Scanner( new FileReader(filename));
}
the Error generated:
blah.java:72: cannot find symbol
symbol : method lastIndexOf(java.lang.String)
location: class java.util.Scanner
filename = readLine.next(2,readLine.lastIndexOf(""));
^
1 error
The same error is generated when i tried to use ".length" method that should be built into java...
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评论（2）
看来
readLine的类型为Scanner并且您正在尝试调用lastIndexOf()但该方法不属于扫描仪类It seems
readLineis of typeScannerand you are trying to invokelastIndexOf()but thi method doesn't belong toScannerclass您的 readLine 是 java.util.Scanner...我猜您认为它是 java.lang.String。
Your
readLineis java.util.Scanner... I guess you're thinking that it's a java.lang.String.