Java 无法实例化类型扫描程序
我是Java新手。我想通过扫描仪读取输入。 我收到错误,因为无法“实例化类型扫描程序”Java 无法实例化类型扫描程序,java,java.util.scanner,Java,Java.util.scanner,我是Java新手。我想通过扫描仪读取输入。 我收到错误,因为无法“实例化类型扫描程序” import java.util.*; import java.io.File; public class Factors { //string declaration static String filename; public static void main(String args[]){ //scanner initialization, needs to be
import java.util.*;
import java.io.File;
public class Factors {
//string declaration
static String filename;
public static void main(String args[]){
//scanner initialization, needs to be done in every program that reads from user
Scanner input = new Scanner(System.in);
int caseIndex=0;
//prompts user for filename
System.out.println("Please enter the name of the file you would like to read from.");
filename = input.nextString();
//checks if filename exists
if(input.exists())
System.out.println(inp.getName() + "exists!");
else
System.out.println("File name does not exist!");
}
}
我不明白我缺少什么。
请帮忙。提前感谢。
Scanner
没有方法nextString()
和exists()
方法。我想你的要求是检查文件是否存在。这样做:
import java.util.*;
import java.io.File;
public class Factors
{
static String filename;
public static void main(String[] args)
{
//scanner initialization, needs to be done in every program that reads from user
Scanner input = new Scanner(System.in);
int caseIndex=0;
//prompts user for filename
System.out.println("Please enter the name of the file you would like to read from.");
filename = input.nextLine();
File file=new File(filename);
//checks if filename exists
if(file.exists())
System.out.println(file.getName() + "exists!");
else
System.out.println("File name does not exist!");
}
}
请添加相关代码。否则,我们只能猜测出哪里出了问题。有多个
扫描仪类型。您确定正在使用java.util.Scanner
?java区分大小写。确保有新的扫描仪(…)而不是新的扫描仪(…)导入java.util.Scanner;公共类StringVariables{Scanner user_input=new Scanner(System.in);}添加了代码,但未获得输出