问题

我想读取使用PuttyGen生成的私钥和公钥，我使用openssl将它们转换为DER格式。

```java
String[] execStr = {"openssl","pkcs8", "-topk8", "-inform", "PEM", "-outform","DER", "-in", "src\\srcData\\openssh1\\privateKey.pem","-out", "src\\srcData\\openssh1\\privateKey.der" };

File execDir = new File("C:\\openssl-1.0.2d-fips-2.0.10\\bin");

Runtime.getRuntime().exec(execStr,null,execDir);

但是我得到了这个错误：

Exception in thread "main" java.io.IOException: Cannot run program "openssl" (in directory "C:\openssl-1.0.2d-fips-2.0.10\bin"): CreateProcess error=2, 系统找不到指定的文件。
	at java.lang.ProcessBuilder.start(ProcessBuilder.java:1059)
	at java.lang.Runtime.exec(Runtime.java:631)
	at PrivateKeyReader.get(PrivateKeyReader.java:21)
	at Test1.main(Test1.java:50)
Caused by: java.io.IOException: CreateProcess error=2, 系统找不到指定的文件。
	at java.lang.ProcessImpl.create(Native Method)
	at java.lang.ProcessImpl.<init>(ProcessImpl.java:455)
	at java.lang.ProcessImpl.start(ProcessImpl.java:151)
	at java.lang.ProcessBuilder.start(ProcessBuilder.java:1040)
	... 3 more

在这里，我无法找出确切的问题，如果有人知道，请告诉我。

<details>
<summary>英文:</summary>

I want to read private and public key generated using PuttyGen for that I used openssl to convert them into DER format.

String[] execStr = {"openssl","pkcs8", "-topk8", "-inform", "PEM", "-outform","DER", "-in", "src\srcData\openssh1\privateKey.pem","-out", "src\srcData\openssh1\privateKey.der" };

File execDir = new File("C:\openssl-1.0.2d-fips-2.0.10\bin");

Runtime.getRuntime().exec(execStr,null,execDir);

But I am getting this error:

Exception in thread "main" java.io.IOException: Cannot run program "openssl" (in directory "C:\openssl-1.0.2d-fips-2.0.10\bin"): CreateProcess error=2, The system cannot find the file specified
at java.lang.ProcessBuilder.start(ProcessBuilder.java:1059)
at java.lang.Runtime.exec(Runtime.java:631)
at PrivateKeyReader.get(PrivateKeyReader.java:21)
at Test1.main(Test1.java:50)
Caused by: java.io.IOException: CreateProcess error=2, The system cannot find the file specified
at java.lang.ProcessImpl.create(Native Method)
at java.lang.ProcessImpl.<init>(ProcessImpl.java:455)
at java.lang.ProcessImpl.start(ProcessImpl.java:151)
at java.lang.ProcessBuilder.start(ProcessBuilder.java:1040)
... 3 more

Here I am not able figure out the exact issue, please let me know if anyone know it.

</details>


# 答案1
**得分**: 0

我明白你已经下载了`openssl-1.0.2d-fips-2.0.10`的Windows版本。位于bin文件夹中的可执行文件被称为`openssl.exe`，而不是`openssl`。因此，你会遇到`系统找不到指定的文件`错误。因此，你的`execStr`应该是`String[] execStr = {&quot;openssl.exe&quot;, ...}`

为了防止将来出现这个问题，你可以让Windows资源管理器显示完整的`openssl.exe`文件名，而不是`openssl`，可以按照这里的说明进行操作：[这里](https://answers.microsoft.com/en-us/windows/forum/all/in-win10-how-to-show-the-file-extension-for/ed21ff20-cdb3-4263-9c7d-fc6ed125fc82)。

此外，请注意，当你将`C:\\openssl-1.0.2d-fips-2.0.10\\bin`作为`execDir`时，路径`src\\srcData\\openssh1\\privateKey.pem`会相对于`execDir`进行解释。因此，你应该将其转换为绝对路径，使用以下方法：
```java
File inputFile = new File(&quot;src\\srcData\\openssh1\\privateKey.pem&quot;);

String[] execStr = {&quot;openssl.exe &quot;, ..., &quot;-in&quot;, inputFile.getCanonicalPath(), ... };

同样的方法也适用于输出文件。

File inputFile = new File("src\\srcData\\openssh1\\privateKey.pem");

String[] execStr = {"openssl.exe ", ..., "-in", inputFile.getCanonicalPath(), ... };