GWT中RequestBuilder应用贴士

GET请求

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String url = // 动态生成
RequestBuilder builder = new RequestBuilder(RequestBuilder.GET,	URL.encode(url)); //若url中包含无效字符（像空格等），需要进行编码

builder.setCallback(new RequestCallback() {
	public void onError(Request request, Throwable exception) {
		// 异常处理
	}

	public void onResponseReceived(Request request, Response response) {
		// 根据响应状态码进行处理
		if(Response.SC_OK == response.getStatusCode){
			// 成功响应的处理
			response.getText();
			...
		}
		// 其它状态的处理，可选
	}
});

// 发送请求
builder.send();

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POST请求

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String url = // 动态生成
RequestBuilder builder = new RequestBuilder(RequestBuilder.POST,URL.encode(url));
// 用post方法提交表单数据，需要设置Content-Type
builder.setHeader("Content-Type", "application/x-www-form-urlencoded");
// 将表单的数据转为字符串，作为RequestData设置给builder
String form = "name=aaa&age=13";
// setRequestData()必须在send()之前调用才有效
builder.setRequestData(form);

builder.setCallback(new RequestCallback() {
	// 同上GET请求的实现
});
builder.send();

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等效的另一种写法：??

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String url = // 动态生成
RequestBuilder builder = new RequestBuilder(RequestBuilder.POST,URL.encode(url));
builder.setHeader("Content-Type", "application/x-www-form-urlencoded");
String form = "name=aaa&age=13";
builder.sendRequest(form,newRequestCallback() {
	// 同上GET请求的实现
});

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注意，对GET请求使用setRequestData()是无效的。

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REST请求

GWT没有在api中预设除GET和POST之外的方法，但可以通过继承RequestBuilder来扩展这样的能力。

public class RestRequestBuilder extends RequestBuilder {

	public static final String METHOD_GET = "GET";
	public static final String METHOD_PUT = "PUT";
	public static final String METHOD_POST = "POST";
	public static final String METHOD_DELETE = "DELETE";
	
	public RestRequestBuilder(String httpMethod, String url) {
		super(httpMethod, url);
	}

}