如果我想从文本文件中读取文件并将其存储在数组中，则每一行都将转到正确的数组 这是文本文件
111111,34,24.5，第一行
222222,53,22.0，第二行
333333，，32.0，第三行
44444,22,12.6，
如果通过异常显示“标题丢失”或类似内容，则该行为空。 如果数组length == 4然后按顺序显示行，但是长度小于4并且缺少行，则会产生代码，但抛出异常，但是当我要放置最后一个array [3]时会出现错误。看一下是否可以看到会有所帮助的错误
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class Itry {
public static void main(String[] args) {
// TODO Auto-generated method stub
String [] splitArray = new String[4];
String line = "";
String array1, description;
int number;
double price;
// Total sales
double total = 0;
Scanner keyboard = new Scanner (System.in);
// Allow the user to enter the name of text file that the data is stored in
System.out.println("This program will try to read data from a text file ");
System.out.print("Enter the file name: ");
String filename = keyboard.nextLine();
Scanner fileReader = null;
try {
File Fileobject = new File (filename);
fileReader = new Scanner (Fileobject);
System.out.println("\nTransactions");
System.out.println("================");
while(fileReader.hasNext())
{
// Contains stock code,Quantity,Price,Description
line = fileReader.nextLine();// Read a line of data from text file
splitArray = line.split(",");
// check to make sure there are 4 parts in splitArray
if(splitArray.length == 4)
{
// remove spaces
splitArray[0] = splitArray[0].trim();
splitArray[1] = splitArray[1].trim();
splitArray[2] = splitArray[2].trim();
splitArray[3] = splitArray[3].trim();
// Extract each item into an appropriate
// variable
try {
array1 = splitArray[0];
number = Integer.parseInt(splitArray[1]);
price = Double.parseDouble(splitArray[2]);
description = splitArray[3];
// Output item
System.out.println("Sold "+String.format("%-5d", number) +
String.format("%-12s", description )+ " at "+"£"+
String.format("%-5.2f", price));
// Compute total
total += number * price;
} // end of try
catch(NumberFormatException e)
{
System.out.println("Error: Cannot convert to number");
}
} //end of if
else if (splitArray[0].length()<1) {
try { splitArray[0] = splitArray[0].trim();
System.out.println(" Title is missing "+" "+splitArray[1] +""+splitArray[2]+"");
}
catch(NumberFormatException e)
{
System.out.println("Error: Cannot convert to number");
}
}
else if (splitArray[1].length()<=1) {
try { splitArray[1] = splitArray[1].trim();
System.out.println(splitArray[0]+" "+" here is missing " +""+splitArray[2] );
}
catch(NumberFormatException e)
{
System.out.println("Error: Cannot convert to number");
}}
else if (splitArray[2].length()<=1) {
try { splitArray[2] = splitArray[2].trim();
System.out.println(splitArray[0]+" "+splitArray[1] +""+" here is missing "+splitArray[3]);
}
catch(NumberFormatException e)
{
System.out.println("Error: Cannot convert to number");
}}
else if (splitArray[3].length()<=1) {
try { splitArray[3] = splitArray[3].trim();
System.out.println(splitArray[0]+" "+splitArray[1] +""+splitArray[2]+"title is missing");
}
catch(NumberFormatException e)
{
System.out.println("Error: Cannot convert to number");
}}
}//end of while
System.out.printf("\nTotal sales: £"+String.format("%-6.2f", total));
}// end of try block
catch (FileNotFoundException e)
{
System.out.println("Error - File does not exist");
}
}
}
答案 0 :(得分：1)
您可以执行以下操作：
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
// TODO Auto-generated method stub
String[] splitArray = new String[4];
String line = "";
String array1, description;
int number;
double price;
// Total sales
double total = 0;
Scanner keyboard = new Scanner(System.in);
// Allow the user to enter the name of text file that the data is stored in
System.out.println("This program will try to read data from a text file ");
System.out.print("Enter the file name: ");
String filename = keyboard.nextLine();
Scanner fileReader = null;
try {
File Fileobject = new File(filename);
fileReader = new Scanner(Fileobject);
System.out.println("\nTransactions");
System.out.println("================");
int count = 1;
while (fileReader.hasNext()) {
// Contains stock code,Quantity,Price,Description
line = fileReader.nextLine();// Read a line of data from text file
try {
if (line != null && line.length() > 0) {
splitArray = line.split(",");
// check to make sure there are 4 parts in splitArray
if (splitArray.length == 4) {
// remove spaces
splitArray[0] = splitArray[0].trim();
splitArray[1] = splitArray[1].trim();
splitArray[2] = splitArray[2].trim();
splitArray[3] = splitArray[3].trim();
// Extract each item into an appropriate variable
try {
array1 = splitArray[0];
number = Integer.parseInt(splitArray[1]);
price = Double.parseDouble(splitArray[2]);
description = splitArray[3];
// Output item
System.out.println(
"Sold " + String.format("%-5d", number) + String.format("%-12s", description)
+ " at " + "£" + String.format("%-5.2f", price));
// Compute total
total += number * price;
} catch (NumberFormatException e) {
System.out.println("Error in line#" + count + ": insufficient/invalid data");
}
} else {
throw new IllegalArgumentException(
"Error in line#" + count + ": insufficient/invalid data");
}
} else {
throw new IllegalArgumentException("Line#" + count + " is empty");
}
} catch (IllegalArgumentException e) {
System.out.println(e.getMessage());
}
count++;
} // end of while
System.out.printf("\nTotal sales: £" + String.format("%-6.2f", total));
} catch (FileNotFoundException e) {
System.out.println("Error - File does not exist");
}
}
}
示例运行：
This program will try to read data from a text file
Enter the file name: data2.txt
Transactions
================
Sold 34 Apple at £24.50
Line#2 is empty
Sold 53 Mango at £22.00
Line#4 is empty
Error in line#5: insufficient/invalid data
Line#6 is empty
Error in line#7: insufficient/invalid data
Total sales: £1999.00
data2.txt的内容：
111111,34,24.5,Apple
222222,53,22.0,Mango
333333,,32.0,Orange
44444,22,12.6,