java.lang.NumberFormatException：对于输入字符串：“1”(java.lang.NumberFormatException: For input string: “1”)

java.lang.NumberFormatException：对于输入字符串：“1”(java.lang.NumberFormatException: For input string: “1”)

“out.txt”的内容是

1

我的JAVA代码是这样的。

int val=0; BufferedReader br = new BufferedReader(new FileReader("out.txt")); while(true) { String line = br.readLine(); if (line==null) break; val=Integer.parseInt(line); } br.close();

和调试器说，

java.lang.NumberFormatException：对于输入字符串：“1”

我需要使用“out.txt”中的1。 我如何使用1作为整数？ 感谢您的关注 ：）

"out.txt" content is

1

My JAVA code is like this.

int val=0; BufferedReader br = new BufferedReader(new FileReader("out.txt")); while(true) { String line = br.readLine(); if (line==null) break; val=Integer.parseInt(line); } br.close();

and debugger says,

java.lang.NumberFormatException: For input string: "1"

i need to use 1 from "out.txt". How can i use 1 as Integer? Thank you for your attention :)

最满意答案

你必须有尾随的空格。 使用trim()函数如下：

val = Integer.parseInt(line.trim());

这是代码片段：

int val = 0; BufferedReader br = new BufferedReader(new FileReader("out.txt")); String line = null; while(true) { line = br.readLine(); if (line == null) break; val = Integer.parseInt(line.trim()); } br.close();

此外，如果要检查String是null还是empty您可以开始使用Apache Commons StringUtils ，如下所示：

if (StringUtils.isEmpty(line)) break;

You must be having the trailing whitespaces. Use the trim() function as follows:

val = Integer.parseInt(line.trim());

Here is the code snippet:

int val = 0; BufferedReader br = new BufferedReader(new FileReader("out.txt")); String line = null; while(true) { line = br.readLine(); if (line == null) break; val = Integer.parseInt(line.trim()); } br.close();

Also, if you want to check whether String is null or empty you can start using the Apache Commons StringUtils as follows:

if (StringUtils.isEmpty(line)) break;