golang json.NewDecoder(reader).Decode invalid character '<' looking for beginning of value

这个错误通常发生在 JSON 数据格式不正确的情况下。例如，JSON 数据可能以非法字符（例如 '<'）开头，这会导致 `json.NewDecoder(reader).Decode()` 方法无法解码 JSON 数据。

为了解决这个问题，您需要检查 JSON 数据是否格式正确。您可以使用在线 JSON 验证器（例如 https://jsonlint.com/）来检查 JSON 数据是否有效。如果JSON数据无效，则需要将其修复为有效的 JSON 格式。

如果在修复 JSON 数据格式后仍然遇到此错误，请确保您的输入数据是来自预期来源，并且没有被意外修改或损坏。

相关问题

golang invalid character 'ï' looking for beginning of value

This error message usually occurs when you have a non-ASCII character in your code, such as the character ï. Go uses UTF-8 encoding, so if you accidentally include a character that is not part of the UTF-8 character set, it will result in this error.

To fix this error, you should check your code for any non-ASCII characters and remove them. You can use a text editor that supports UTF-8 encoding, such as Notepad++, to identify and remove any non-ASCII characters. Alternatively, you can try saving the file in UTF-8 encoding and see if that resolves the issue.

If you are still having trouble, you may want to check the encoding of any files that your code is importing, as these could also contain non-ASCII characters that are causing the error.

golang io.WriterAt 报错 invalid argument

当使用 `io.WriterAt` 接口时，如果传入的 `offset` 参数小于 0 或者大于文件大小，会返回 `invalid argument` 错误。这是因为 `WriterAt` 接口需要确保写入的位置不会超出文件的范围。

你可以检查一下写入的位置是否正确，或者尝试使用其他的写入方式。同时，也可以参考下面的代码示例：

package main

import (
	"fmt"
	"os"
)

func main() {
	file, err := os.Create("test.txt")
	if err != nil {
		fmt.Println(err)
		return
	}
	defer file.Close()

	data := []byte("Hello, world!")
	offset := int64(10)

	n, err := file.WriteAt(data, offset)
	if err != nil {
		fmt.Println(err)
		return
	}

	fmt.Printf("Wrote %d bytes at offset %d\n", n, offset)
}

在以上示例中，我们创建了一个文件 `test.txt`，然后写入了一些数据，并指定了一个偏移量。如果写入成功，我们会打印出写入的字节数和偏移量。