fix: require explicit JWT secret configuration (#301)

Author: hexqi

base/src/main/java/com/tinyengine/it/login/utils/JwtUtil.java

@@ -17,20 +17,21 @@
 import io.jsonwebtoken.Claims;
 import io.jsonwebtoken.ExpiredJwtException;
 import io.jsonwebtoken.Jwts;
-import io.jsonwebtoken.MalformedJwtException;
-import io.jsonwebtoken.security.Keys;
-import lombok.extern.slf4j.Slf4j;
-import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.stereotype.Component;
-
-import javax.crypto.SecretKey;
-import java.util.ArrayList;
-import java.util.Date;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.Optional;
-import java.util.stream.Collectors;
+import io.jsonwebtoken.MalformedJwtException;
+import io.jsonwebtoken.security.Keys;
+import jakarta.annotation.PostConstruct;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+
+import javax.crypto.SecretKey;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.Date;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
 
 /**
  * Jwt util
@@ -39,22 +40,38 @@
 @Slf4j
 public class JwtUtil {
 
-    @Autowired
-    private TokenBlacklistService tokenBlacklistService;
-
-    private static final long EXPIRATION_TIME = 21600000L; // 6小时 = 6 * 60 * 60 * 1000 = 21600000 毫秒
-    private static final String DEFAULT_SECRET = "tiny-engine-backend-secret-key-at-jwt-login";
-
-    // 避免启动时环境变量未加载的问题
-    private static String getSecretString() {
-        return Optional.ofNullable(System.getenv("SECRET_STRING"))
-            .orElse(DEFAULT_SECRET);
-    }
-
-    public static SecretKey getSecretKey() {
-
-        return Keys.hmacShaKeyFor(getSecretString().getBytes());
-    }
+    @Autowired
+    private TokenBlacklistService tokenBlacklistService;
+
+    private static final long EXPIRATION_TIME = 21600000L; // 6小时 = 6 * 60 * 60 * 1000 = 21600000 毫秒
+    private static final String SECRET_ENV_NAME = "SECRET_STRING";
+
+    @PostConstruct
+    public void validateSecretConfiguration() {
+        try {
+            getSecretKey();
+        } catch (Exception e) {
+            throw new IllegalStateException(
+                "JWT secret is not configured correctly. Set environment variable "
+                    + SECRET_ENV_NAME + " to a strong value before starting the service.",
+                e
+            );
+        }
+    }
+
+    private static String getSecretString() {
+        String secret = System.getenv(SECRET_ENV_NAME);
+        if (secret == null || secret.isBlank()) {
+            throw new IllegalStateException(
+                "Missing required environment variable " + SECRET_ENV_NAME + " for JWT signing."
+            );
+        }
+        return secret;
+    }
+
+    public static SecretKey getSecretKey() {
+        return Keys.hmacShaKeyFor(getSecretString().getBytes(StandardCharsets.UTF_8));
+    }
 
     /**
      * 生成包含完整用户信息的 JWT Token（支持 Tenant 对象和 Map 两种格式）