java type_error ai_generated true

java.lang.NumberFormatException: For input string: "..."

ID: java/numberformatexception-for-input-string

Also available as: JSON · Markdown · 中文
90%Fix Rate
90%Confidence
1Evidence
2023-03-10First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
Java 8 active — — —
Java 11 active — — —
Java 17 active — — —
Java 21 active — — —

Root Cause

Attempting to parse a string that does not contain a parsable number, often due to whitespace, null, or unexpected characters.

generic

中文

尝试解析一个不包含可解析数字的字符串，通常由于空白字符、null 或意外字符。

Official Documentation

https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/lang/NumberFormatException.html

Workarounds

  1. 90% success Use try-catch with NumberFormatException and provide a default value: 'int value; try { value = Integer.parseInt(input.trim()); } catch (NumberFormatException e) { value = 0; }' 
    Use try-catch with NumberFormatException and provide a default value: 'int value; try { value = Integer.parseInt(input.trim()); } catch (NumberFormatException e) { value = 0; }'
  2. 85% success Validate input with a regex before parsing: 'if (input != null && input.matches("\\d+")) { int value = Integer.parseInt(input); } else { /* handle error */ }' 
    Validate input with a regex before parsing: 'if (input != null && input.matches("\\d+")) { int value = Integer.parseInt(input); } else { /* handle error */ }'

中文步骤

  1. Use try-catch with NumberFormatException and provide a default value: 'int value; try { value = Integer.parseInt(input.trim()); } catch (NumberFormatException e) { value = 0; }'
  2. Validate input with a regex before parsing: 'if (input != null && input.matches("\\d+")) { int value = Integer.parseInt(input); } else { /* handle error */ }'

Dead Ends

Common approaches that don't work:

  1. 95% fail

    Using Integer.valueOf() without try-catch on user input will crash the application if input is invalid.

  2. 80% fail

    Assuming locale-specific number formats (e.g., commas in European locales) are supported by default can cause parsing failures.