feat: 优化代码

app/src/main/java/io/legado/app/web/controller/BookshelfController.kt

@@ -23,7 +23,7 @@ class BookshelfController {
     fun getChapterList(parameters: Map<String, List<String>>): ReturnData {
         val bookUrl = parameters["url"]?.get(0)
         val returnData = ReturnData()
-        if (bookUrl == null) {
+        if (bookUrl.isNullOrEmpty()) {
             return returnData.setErrorMsg("参数url不能为空，请指定书籍地址")
         }
         val chapterList = App.db.bookChapterDao().getChapterList(bookUrl)
@@ -34,7 +34,7 @@ class BookshelfController {
         val bookUrl = parameters["url"]?.get(0)
         val index = parameters["index"]?.get(0)?.toInt()
         val returnData = ReturnData()
-        if (bookUrl == null) {
+        if (bookUrl.isNullOrEmpty()) {
             return returnData.setErrorMsg("参数url不能为空，请指定书籍地址")
         }
         if (index == null) {

app/src/main/java/io/legado/app/web/controller/SourceController.kt

@@ -58,12 +58,12 @@ class SourceController {
     }
 
     fun getSource(parameters: Map<String, List<String>>): ReturnData {
-        val strings = parameters["url"]
+        val url = parameters["url"]?.get(0)
         val returnData = ReturnData()
-        if (strings == null) {
+        if (url.isNullOrEmpty()) {
             return returnData.setErrorMsg("参数url不能为空，请指定书源地址")
         }
-        val bookSource = App.db.bookSourceDao().getBookSource(strings[0])
+        val bookSource = App.db.bookSourceDao().getBookSource(url)
             ?: return returnData.setErrorMsg("未找到书源，请检查书源地址")
         return returnData.setData(bookSource)
     }