HTTP 示例
本节通过几个示例总结了我们对 Spring Integration 的 HTTP 支持的介绍。
多部分 HTTP 请求 —— RestTemplate (客户端) 和 Http 入口网关 (服务器)
此示例展示了使用 Spring 的 RestTemplate 发送多部分 HTTP 请求并使用 Spring Integration HTTP 入站适配器接收它有多么简单。我们创建一个 MultiValueMap 并用多部分数据填充它。RestTemplate 负责其余的工作(没有双关的意思),通过将其转换为 MultipartHttpServletRequest。这个特定的客户端发送一个包含公司名称和图像文件(公司徽标)的多部分 HTTP 请求。以下列表显示了该示例:
RestTemplate template = new RestTemplate();
String uri = "http://localhost:8080/multipart-http/inboundAdapter.htm";
Resource s2logo =
   new ClassPathResource("org/springframework/samples/multipart/spring09_logo.png");
MultiValueMap map = new LinkedMultiValueMap();
map.add("company", "SpringSource");
map.add("company-logo", s2logo);
HttpHeaders headers = new HttpHeaders();
headers.setContentType(new MediaType("multipart", "form-data"));
HttpEntity request = new HttpEntity(map, headers);
ResponseEntity<?> httpResponse = template.exchange(uri, HttpMethod.POST, request, null);
那就是客户端所需要的全部。
在服务器端,我们有以下配置:
<int-http:inbound-channel-adapter id="httpInboundAdapter"
    channel="receiveChannel"
    path="/inboundAdapter.htm"
    supported-methods="GET, POST"/>
<int:channel id="receiveChannel"/>
<int:service-activator input-channel="receiveChannel">
    <bean class="org.springframework.integration.samples.multipart.MultipartReceiver"/>
</int:service-activator>
<bean id="multipartResolver"
    class="org.springframework.web.multipart.commons.CommonsMultipartResolver"/>
httpInboundAdapter 接收请求并将其转换为有效载荷为 LinkedMultiValueMap 的 Message。然后我们在 'multipartReceiver' 服务激活器中解析它,如下例所示:
public void receive(LinkedMultiValueMap<String, Object> multipartRequest){
    System.out.println("### Successfully received multipart request ###");
    for (String elementName : multipartRequest.keySet()) {
        if (elementName.equals("company")){
            System.out.println("\t" + elementName + " - " +
                ((String[]) multipartRequest.getFirst("company"))[0]);
        }
        else if (elementName.equals("company-logo")){
            System.out.println("\t" + elementName + " - as UploadedMultipartFile: " +
                ((UploadedMultipartFile) multipartRequest
                    .getFirst("company-logo")).getOriginalFilename());
        }
    }
}
你应该看到以下输出:
### Successfully received multipart request ###
   company - SpringSource
   company-logo - as UploadedMultipartFile: spring09_logo.png