使用 GWT 连接到 SQL Server
我目前正在从事一个班级项目，我们正在使用 sqlplus 上的数据库和 GWT 作为用户界面来实现 Twitter 的基本实现。
我的后端数据库访问部分很简单。我有一些类包含相应的访问/修改数据库的方法，您只需传入 Connection 对象作为每个类的构造函数。基本上，每个方法都会启动一条语句，执行一个查询，并在必要时解析 ResultSet。
然而，我的合作伙伴正在研究前端 GWT 部分，她无法弄清楚如何在她的代码中连接到 SQL 服务器。例如，在主页上，我们有几个文本字段和一个确认按钮。我对 GWT 一无所知，所以这可能是完全错误的，但是您可以在确认按钮的 onclick 侦听器内创建我为后端实现的类的新实例，并调用适当的函数来修改数据库吗？我的搭档说了一些关于创建新的异步接口和类的事情，但我真的不明白为什么她需要这样做，因为我的印象是她可以在适当的位置调用我的函数来修改/访问数据库。
预先感谢您的反馈！
初级 DB 学生
I'm currently working on a class project, and we're doing a basic implementation of Twitter using database on sqlplus and GWT for user interface.
My backend database access portion is simple. I have a few classes that contain methods to access/modify the database accordingly, and you only need to pass in the Connection object as constructor for each of the classes. Basically, each of the methods starts a Statement, executes a query, and parse the ResultSet if necessary.
However, my partner, who's working on the frontend GWT part, cannot figure out how to connect to the SQL servers in her code. For example, on the main page, we have several text fields and a confirmation button. I don't know anything about GWT, so this might be completely wrong, but can you just create new instances of the classes I implemented for backend inside the confirmation button's onclick listener and call the appropriate function to modify the database? My partner said something about creating new async interfaces and classes, but I don't really understand why she needs to do that, since I was under the impression that she can just call my functions at appropriate spots to modify/access database.
Thanks in advance for the feedbacks!
Beginning DB student
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GWT 是一个将代码编译为 JavaScript 的框架，它在客户端（浏览器）上运行。由于浏览器没有连接到数据库服务器的通用接口（通常这不是一个好主意），因此 GWT 无法支持这一点。
您应该研究的是在 GWT 客户端和后端 Web 服务器之间构建通信通道，并使该服务器与数据库服务器通信：
一个好的开始是：
http://code.google.com/webtoolkit/doc/latest/tutorial /RPC.html
GWT is a framework that compiles code to javascript, which runs on the client side (the browser). As a browser has no common interface to connect to a database server (and usually that would be a bad idea anyway), GWT can't support that.
What you should look into, is building a communication channel between the GWT client and a back-end web server, and have that server communicating with the database server:
A good start would be:
http://code.google.com/webtoolkit/doc/latest/tutorial/RPC.html
RequestFactory 是 GWT-RPC 的替代方案，可能更适合您因为它旨在用于面向数据的服务。
RequestFactory is an alternative to GWT-RPC that could be more suitable for you since it's intended for data-oriented services.