尝试将字符串解析为整数时的NumberFormatException

Question

Exception in thread "main" java.lang.NumberFormatException: For input string: " 400"
        at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
        at java.lang.Integer.parseInt(Integer.java:470)
        at java.lang.Integer.parseInt(Integer.java:514)
        at Library.loadBooks(Library.java:191)
        at UseLibrary.main(UseLibrary.java:102)

有什么问题？

Answer 1

你有一个空格" 400",导致一个NumberFormatException.

String.trim()在尝试解析之前使用.

阅读文档以获取更多信息String.trim().