优化 toArray 预设大小的数组替换为零长度数组

modules/core/src/main/java/com/jeesite/common/utils/excel/fieldtype/PostListType.java

@@ -41,7 +41,7 @@ public class PostListType implements FieldType {
 				}
 			}
 		}
-		return list.size() > 0 ? list.toArray(new String[list.size()]) : null;
+		return !list.isEmpty() ? list.toArray(new String[0]) : null;
 	}
 
 	/**

modules/core/src/main/java/com/jeesite/common/utils/excel/fieldtype/RoleListType.java

@@ -41,7 +41,7 @@ public class RoleListType implements FieldType {
 				}
 			}
 		}
-		return list.size() > 0 ? list.toArray(new String[list.size()]) : null;
+		return !list.isEmpty() ? list.toArray(new String[0]) : null;
 	}
 
 	/**

modules/core/src/main/java/com/jeesite/modules/sys/utils/EmpUtils.java

@@ -263,7 +263,7 @@ public class EmpUtils {
 				}
 			}
 		});
-		return list.toArray(new String[list.size()]);
+		return list.toArray(new String[0]);
 	}
 	
 	/**