1.使用 keytool 导出jks文件的 crt 文件

先查询别名 

keytool -list -keystore oauth2.jks -storepass [你的密钥库密码]

导出crt 文件

keytool -exportcert -alias  oauth2 -keystore oauth2.jks -file 777.crt 

2.查看公钥

打开PowerShell

# 设置.crt文件的路径  
$certPath = "E:\jcdProject\gitee\jiweiduban\pengyue-supervise\supervise-oauth2\src\main\resources\666.crt"  
  
# 加载证书  
$cert = New-Object System.Security.Cryptography.X509Certificates.X509Certificate2($certPath)  
  
# 获取公钥  
$publicKey = $cert.GetPublicKey()  
  
# 将公钥转换为Base64编码的字符串  
$base64PublicKey = [System.Convert]::ToBase64String($publicKey)  
  
# 输出Base64编码的公钥  
Write-Host $base64PublicKey