java - 创建一个java REST客户端来调用spring boot REST API

Question

我有一个 springboot 项目，只需要 POST JSON 字符串，我使用 gson 将其转换为 HashMap。我使用 Postman 作为 POST 进行了测试，并将正文添加为 props ，并使用 json 字符串，如 {'fistname': 'John', 'lastname' : 'Doe'},翻译为 props = {'fistname': 'John', 'lastname' : 'Doe'}。它按预期工作

@RequestMapping(value = "/rest", method = RequestMethod.POST)
    protected String parse(@RequestParam("props") String props) {
    Gson gson = new Gson();
    Map<String, String> params = new HashMap<String, String>();
    params = gson.fromJson(props, Map.class);

    // Rest of the process
}

另一方面，我有一个JavaEE项目，需要调用这个API

protected void callREST() {

      try {
            String json = someClass.getDate() //retrieved from database which is stored as json structure
            Map<String, String> props = gson.fromJson(json, Map.class);

            URL url = new URL("http://localhost:9090/myApp/rest");
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setDoOutput(true);
            conn.setRequestMethod("POST");
            conn.setRequestProperty("Content-Type", "application/json");

            DataOutputStream wr = new DataOutputStream( conn.getOutputStream());

            System.out.println(props.toString());
            wr.writeBytes(json.toString());
            wr.flush();
            wr.close();
            if(conn.getResponseCode() != HttpURLConnection.HTTP_CREATED) {
                throw new RuntimeException("Failed :: HTTP error code : " + conn.getResponseCode());
            }

            BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream()));
            String output;
            System.out.println("Output from Server ... \n");
            while((output = br.readLine()) != null) {
                System.out.println(output);
            }

            conn.disconnect();

       } catch(Exception e) {
          //print stack trace
       }
 }

我收到失败::HTTP 错误代码:400。我怀疑 Spring Boot 没有接收到 props 变量中的数据，因为它是 POST 请求。 我应该在客户端代码中添加什么来传递 Prop 和数据以使此调用成功？

Note: JavaEE is running on tomcat :8080, Springboot is running on different tomcat :9090

Answer 1

@RequestParam 表示服务器等待请求 URL 中的参数 http://localhost:9090/myApp/rest?param=..... 但在您的客户端中您正在请求正文中编写 JSON。

尝试在端点中使用@RequestBody注释

protected String parse(@RequestBody String props) {...}