【BUG记录】Apifox 参数传入 + 号变成空格的 BUG

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1. 问题描述

之前写了一个接口，用 Apifox 请求，参数传入一个 +86 的电话，结果到服务器 + 就变成空格了。

Java 接收请求的接口：

2. 原因

2.1 编码

进行 URL 请求的时候我们需要用 URLEncoder 对参数进行编码，下面是编码的规则。

/*** Utility class for HTML form encoding. This class contains static methods* for converting a String to the <CODE>application/x-www-form-urlencoded</CODE> MIME* format. For more information about HTML form encoding, consult the HTML* <A HREF="http://www.w3.org/TR/html4/">specification</A>.** <p>* When encoding a String, the following rules apply:** <ul>* <li>The alphanumeric characters &quot;{@code a}&quot; through*     &quot;{@code z}&quot;, &quot;{@code A}&quot; through*     &quot;{@code Z}&quot; and &quot;{@code 0}&quot;*     through &quot;{@code 9}&quot; remain the same.* <li>The special characters &quot;{@code .}&quot;,*     &quot;{@code -}&quot;, &quot;{@code *}&quot;, and*     &quot;{@code _}&quot; remain the same.* <li>The space character &quot; &nbsp; &quot; is*     converted into a plus sign &quot;{@code +}&quot;.* <li>All other characters are unsafe and are first converted into*     one or more bytes using some encoding scheme. Then each byte is*     represented by the 3-character string*     &quot;<i>{@code %xy}</i>&quot;, where <i>xy</i> is the*     two-digit hexadecimal representation of the byte.*     The recommended encoding scheme to use is UTF-8. However,*     for compatibility reasons, if an encoding is not specified,*     then the default encoding of the platform is used.* </ul>** <p>* For example using UTF-8 as the encoding scheme the string &quot;The* string &#252;@foo-bar&quot; would get converted to* &quot;The+string+%C3%BC%40foo-bar&quot; because in UTF-8 the character* &#252; is encoded as two bytes C3 (hex) and BC (hex), and the* character @ is encoded as one byte 40 (hex).** @author  Herb Jellinek* @since   JDK1.0*/
public class URLEncoder {...
}

直接上 GPT，解释如下：

• 保留字符：

  • 字母（a-z, A-Z）和数字（0-9）保持不变。
  • 特殊字符 .（点）、-（减号）、*（星号）和 _（下划线）保持不变。

• 空格：

  • 空格字符（ ）被转换为加号（+）。

• 其他字符：

  • 所有其他字符被认为是“不安全的”，需要先使用某种编码方案（如UTF-8）转换为一个或多个字节，然后每个字节表示为%xy，其中xy是该字节的十六进制表示。

举个例子：假设使用UTF-8编码，字符串 “The string ü@foo-bar” 将被转换为 “The+string+%C3%BC%40foo-bar”，因为：
字符 ü 在UTF-8中编码为两个字节 C3 和 BC。
字符 @ 编码为一个字节 40。

2.2 解码

编码之后就能发送请求到服务器了，而我们直接在 Postman 上面请求的 URL 如下：

可以理解成编码之后的 URL，所以接收请求的时候同样会进行 URL 解码。那么 URL 是如何解码的呢？我们可以同样到 URLDecoder 里面去找答案：

/*** Utility class for HTML form decoding. This class contains static methods* for decoding a String from the <CODE>application/x-www-form-urlencoded</CODE>* MIME format.* <p>* The conversion process is the reverse of that used by the URLEncoder class. It is assumed* that all characters in the encoded string are one of the following:* &quot;{@code a}&quot; through &quot;{@code z}&quot;,* &quot;{@code A}&quot; through &quot;{@code Z}&quot;,* &quot;{@code 0}&quot; through &quot;{@code 9}&quot;, and* &quot;{@code -}&quot;, &quot;{@code _}&quot;,* &quot;{@code .}&quot;, and &quot;{@code *}&quot;. The* character &quot;{@code %}&quot; is allowed but is interpreted* as the start of a special escaped sequence.* <p>* The following rules are applied in the conversion:** <ul>* <li>The alphanumeric characters &quot;{@code a}&quot; through*     &quot;{@code z}&quot;, &quot;{@code A}&quot; through*     &quot;{@code Z}&quot; and &quot;{@code 0}&quot;*     through &quot;{@code 9}&quot; remain the same.* <li>The special characters &quot;{@code .}&quot;,*     &quot;{@code -}&quot;, &quot;{@code *}&quot;, and*     &quot;{@code _}&quot; remain the same.* <li>The plus sign &quot;{@code +}&quot; is converted into a*     space character &quot; &nbsp; &quot; .* <li>A sequence of the form "<i>{@code %xy}</i>" will be*     treated as representing a byte where <i>xy</i> is the two-digit*     hexadecimal representation of the 8 bits. Then, all substrings*     that contain one or more of these byte sequences consecutively*     will be replaced by the character(s) whose encoding would result*     in those consecutive bytes.*     The encoding scheme used to decode these characters may be specified,*     or if unspecified, the default encoding of the platform will be used.* </ul>* <p>* There are two possible ways in which this decoder could deal with* illegal strings.  It could either leave illegal characters alone or* it could throw an {@link java.lang.IllegalArgumentException}.* Which approach the decoder takes is left to the* implementation.** @author  Mark Chamness* @author  Michael McCloskey* @since   1.2*/public class URLDecoder {...
}

还是一样，直接用 GPT 解释：

• **字母和数字：**字母a到z、A到Z和数字0到9保持不变。
• **特殊字符：**点号.、连字符-、星号*和下划线_保持不变。
• **加号：**加号+被转换为空格字符。
• **百分号编码：**形式为"%xy"的序列被视为表示一个字节，其中xy是该字节的两位十六进制表示。连续的这些字节序列将被替换为那些字节所表示的字符。字符的编码方案可以指定，如果没有指定，则使用平台的默认编码。

比如请求参数：http://localhost:8080/demo/getName?name=.-*_aA0+%2B

服务端这边的接收：.-*_aA0 +，可以看到 + 号解码成空格，同时 %2B 解码成 + 号了。因为 + 的 Ascii 十六进制就是 2B。

3. 解决方法

既然 + 号是被解码成空格了，那我们可以不把 + 号放在 URL 中，可以放在 Body 中，也就是使用 Post 请求，把参数放到请求体中传入就不会解码了。

@RequestMapping("/demo")
@RestController
public class DemoController {@GetMapping("getName")public void reqDemo(@RequestBody DataDemo dataDemo){System.out.println(dataDemo.getName());}
}@Getter
@Setter
public class DataDemo {private String name;
}

输出结果如下：

此外，还有一种方法，就是上面说的：传入 %2B 就行了。

如有错误，欢迎指出！！！