从 GWT 调用远程 Servlet
我试图从 GWT 调用远程 servlet，实际上 GWT-RPC 似乎不起作用，所以我尝试使用 RequestBuilder 来完成它。
代码片段如下：
String url = "http://some-remote-host:8888/GWTJSTest/SomeServlet?name=" + textBox.getText();
RequestBuilder requestBuilder = new RequestBuilder(RequestBuilder.GET, url);
// requestBuilder.setHeader("Origin", "*");
// requestBuilder.setHeader("Access-Control-Allow-Origin", "*");
try
{
requestBuilder.sendRequest(null, new RequestCallback()
{
public void onResponseReceived(Request request, Response response)
{
if (response.getStatusCode() == 200)
{
Window.alert(response.getText());
}else
{
Window.alert(response.getText() + " : " + response.getStatusCode() + response.getStatusText());
}
}
public void onError(Request arg0, Throwable arg1)
{
Window.alert(arg1.toString());
}
});
} catch (RequestException e)
{
Window.alert("CATCH BLOCK: " + e.getMessage());
e.printStackTrace();
}
实际上，IE8 在出现警告消息后返回数据，但 Firefox 不会！这是为什么呢？
如您所见，我正在尝试设置一些请求标头，但没有办法。
I am trying to call remote servlet from GWT, actually the GWT-RPC doesn't seems to work, so I am trying to do it using the RequestBuilder.
Here's the code snippet:
String url = "http://some-remote-host:8888/GWTJSTest/SomeServlet?name=" + textBox.getText();
RequestBuilder requestBuilder = new RequestBuilder(RequestBuilder.GET, url);
// requestBuilder.setHeader("Origin", "*");
// requestBuilder.setHeader("Access-Control-Allow-Origin", "*");
try
{
requestBuilder.sendRequest(null, new RequestCallback()
{
public void onResponseReceived(Request request, Response response)
{
if (response.getStatusCode() == 200)
{
Window.alert(response.getText());
}else
{
Window.alert(response.getText() + " : " + response.getStatusCode() + response.getStatusText());
}
}
public void onError(Request arg0, Throwable arg1)
{
Window.alert(arg1.toString());
}
});
} catch (RequestException e)
{
Window.alert("CATCH BLOCK: " + e.getMessage());
e.printStackTrace();
}
Actually, IE8 returns the data but after a warning message, but Firefox doesn't! Why is this?
As you see, I am trying to set some request headers but no way.
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如果您尝试向自己的服务器和端口（与您的 GWT 页面所在的服务器和端口相同）发出请求，请将第一行替换为：
如果您尝试与不同的服务器或不同的端口通信您自己的服务器，同源策略将阻止您这样做。您需要从您自己的服务器代理它。
If you're trying to make a request to your own server and port (the same one that your GWT page is on), replace the first line with:
If you're trying to talk to a different server, or a different port on your own server, the Same Origin Policy will keep you from doing that. You'll need to proxy it from your own server.
远程 Servlet 需要设置您拥有的 CORS 标头：
或者您可以指定如果您不希望其他域与远程 servlet 交互，则只需使用您自己的域，而不是
*。The remote servlet is the one that needs to set the CORS header that you have:
Alternatively you can specify just your own domain instead of
*if you don't want other domains interacting with the remote servlet.我添加了：
.gwt.xml然后用
JsonpRequestBuilder 替换（在服务器和客户端之间转换GWT-PRCJSONP）I've added :
<add-linker name="xs" />to.gwt.xmlAnd then replaces
GWT-PRCbyJsonpRequestBuilder(transformingJSONPbetween the server and the client)