修复country拼接出现多余的空格问题，修改jdk version

pom.xml

@@ -56,8 +56,8 @@
                 <artifactId>maven-compiler-plugin</artifactId>
                 <version>3.8.0</version>
                 <configuration>
-                    <source>1.8</source>
-                    <target>1.8</target>
+                    <source>11</source>
+                    <target>11</target>
                     <!-- The semantics of this option are reversed, see MCOMPILER-209. -->
                     <useIncrementalCompilation>false</useIncrementalCompilation>
                     <compilerArgs>

src/main/java/com/zdjizhi/function/DosDetectionFunction.java

@@ -312,7 +312,7 @@ public class DosDetectionFunction extends ProcessFunction<DosSketchLog, DosEvent
                         countrySet.add(country);
                     }
                 }
-                countryList = StringUtils.join(countrySet, ", ");
+                countryList = StringUtils.join(countrySet, ",");
                 return countryList;
             } catch (Exception e) {
                 logger.error("{} source IP lists 获取国家失败", sourceIpList, e);