Java 使用 try/catch 块从文本文件中读取
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read from text file using try/catch blocks
提问by theGreggstar
so im trying to read from a file the number of words and adding them up to give and int answer? And help and or suggestions would be nice, and i can only use a try/catch while for loop and if/else/if.... Thanks!
所以我试图从文件中读取单词数并将它们加起来给出和 int 答案？帮助和/或建议会很好，我只能使用 try/catch while for 循环和 if/else/if .... 谢谢！
Here what i got so far:
这是我到目前为止所得到的：
package filereadingexercise2;
import java.io.*;
import java.util.Scanner;
/**
*
* @author theGreggstar
*/
public class FileReadingExercise2
{
/**
* @param args the command line arguments
*/
public static void main(String[] args)
{
Scanner keys = new Scanner(System.in);
String nameOfFile;
System.out.print("Please Enter The Name Of A File Or Directory, or Type Quit To Exit: ");
nameOfFile = keys.nextLine();
Scanner input = null;
try
{
input = new Scanner(new File(nameOfFile));
}
catch(FileNotFoundException s)
{
System.out.println("File does Not Exist Please Try Again: ");
}
while(input.hasNext())
{
String contents = input.next();
int length;
System.out.print(contents);
}
}
}
回答by Elliott Frisch
If I understand you correctly, you want something like this -
如果我理解正确的话，你想要这样的东西——
public static void main(String[] args) {
Scanner keys = new Scanner(System.in);
for (;;) { // Loop forever.
System.out.print("Please Enter The Name Of A File Or "
+ "Directory, or Type Quit To Exit: ");
String nameOfFile = keys.nextLine().trim(); // get the User input.
if (nameOfFile.equalsIgnoreCase("quit")) { // check for exit condition.
break;
}
File f = new File(nameOfFile); // Construct a File.
if (f.exists()) { // Does it exist?
if (f.isFile() && f.canRead()) { // is it a File and can I read it?
Scanner input = null;
try {
input = new Scanner(f); // The Scanner!
while (input.hasNextLine()) {
String contents = input.nextLine();
System.out.println(contents); // Print the lines.
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} finally {
if (input != null) {
input.close(); // Close the file scanner.
}
}
} else if (f.isDirectory()) { // No, it's a directory!
try {
System.out.println("File "
+ f.getCanonicalPath()
+ " is a directory");
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
