Java 中的 NumberFormatException 是什麼?
例子
讓我們看一個簡單的例子來理解這一點。
import java.util.Date;
public class NumberFormatExceptionTestDriver {
public static void main(String[] args) {
try {
// a valid Integer number in the input String
String inputString = "2550";
System.out.println("Integer.pareseInt(" + inputString + ") = " + Integer.parseInt(inputString));
} catch (NumberFormatException e) {
// java.lang.NumberFormatException will be thrown if the
// input string can not be converted to a valid integer
System.out.println("\nNumberFormatException thrown! " + e.getMessage());
}
try {
// a floating number in the input String
// use Float.parseFloat(inputString) to avoid this exception
String inputString = "255.0";
System.out.println("Integer.pareseInt(" + inputString + ") = " + Integer.parseInt(inputString));
} catch (NumberFormatException e) {
System.out.println("\nNumberFormatException thrown! " + e.getMessage());
}
try {
Date day = new Date();
// date containing alpha-numeric data in the input string
String inputString = day.toString();
System.out.println("Integer.pareseInt(" + inputString + ") = " + Integer.parseInt(inputString));
} catch (NumberFormatException e) {
System.out.println("\nNumberFormatException thrown! " + e.getMessage());
}
try {
// numbers with spaces in the input string
String inputString = "1 2 3";
System.out.println("Integer.pareseInt(" + inputString + ") = " + Integer.parseInt(inputString));
} catch (NumberFormatException e) {
System.out.println("\nNumberFormatException thrown! " + e.getMessage());
}
try {
// all letters in the input string
String inputString = "Lubaina Khan";
System.out.println("Integer.pareseInt(" + inputString + ") = " + Integer.parseInt(inputString));
} catch (NumberFormatException e) {
System.out.println("\nNumberFormatException thrown! " + e.getMessage());
}
}
}
輸出
Integer.pareseInt(2550) = 2550 拋出 NumberFormatException!對於輸入字符串:拋出“255.0”NumberFormatException!對於輸入字符串:“Wed Aug 11 08:18:21 PKT 2021”拋出 NumberFormatException!對於輸入字符串:“1 2 3”拋出 NumberFormatException!對於輸入字符串:“Lubaina Khan”
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