update java.getCookie

java.getCookie("http://baidu.com") return user=test;pwd=123
java.getCookie("http://baidu.com", "user") reurn test

app/src/main/assets/updateLog.md

@@ -6,7 +6,7 @@
 **2020/10/23**
 * 修复选择错误的bug
 * 修复长图最后一张不能滚动的bug
-* js添加java.getCookie(sourceUrl)来获取登录后的cookie by [AndyBernie](https://github.com/AndyBernie)
+* js添加java.getCookie(sourceUrl:String, key:String ?=null)来获取登录后的cookie by [AndyBernie](https://github.com/AndyBernie)
 * 修复简繁转换没有处理标题
 
 **2020/10/21**

app/src/main/java/io/legado/app/help/JsExtensions.kt

@@ -123,8 +123,14 @@ interface JsExtensions {
      /**
       *js实现读取cookie
       */
-     fun getCookie(tag: String): String {
+     fun getCookie(tag: String, key: String? = null): String {
-        return CookieStore.getCookie(tag)
+        val cookie = CookieStore.getCookie(tag)
+        val cookieMap = CookieStore.cookieToMap(cookie)
+        return if (key != null) {
+            cookieMap.get(key) ?: ""
+        } else {
+            cookie
+        }
      }
 
     /**

app/src/main/java/io/legado/app/help/http/CookieStore.kt

@@ -43,7 +43,7 @@ object CookieStore : CookiePersistor {
         App.db.cookieDao().delete(NetworkUtils.getSubDomain(url))
     }
 
-    private fun cookieToMap(cookie: String): MutableMap<String, String> {
+    fun cookieToMap(cookie: String): MutableMap<String, String> {
         val cookieMap = mutableMapOf<String, String>()
         if (cookie.isBlank()) {
             return cookieMap