优化isJsonRequest

src/main/java/com/jfinal/core/Controller.java

@@ -94,8 +94,11 @@ public abstract class Controller {
 	 * 判断当前请求是否为 json 格式，contentType 包含 "application/json" 被认定为 json 请求
 	 */
 	public boolean isJsonRequest() {
+		if (request instanceof com.jfinal.core.paragetter.JsonRequest) {
+			return true;
+		}
 		String ct = request.getContentType();
-		return ct != null && ct.indexOf("application/json") != -1;
+		return ct != null && ct.indexOf("json") != -1;
 	}
 	
 	/**