java - 为什么我收到 HTTP 400 错误请求

Question

我正在使用 HTTP 客户端(从 http://www.mkyong.com/java/apache-httpclient-examples/ 复制的代码)发送发布请求。我一直在尝试将它与 http://postcodes.io 一起使用查找大量邮政编码但失败了。根据http://postcodes.io我应该发送一个帖子请求到http://api.postcodes.io/postcodes采用以下 JSON 格式:{"postcodes": ["OX49 5NU", "M32 0JG", "NE30 1DP"]} 但我总是收到 HTTP 响应代码 400。我在下面包含了我的代码。请告诉我我做错了什么？谢谢

private void sendPost() throws Exception {

    String url = "http://api.postcodes.io/postcodes";
    HttpClient client = HttpClientBuilder.create().build();
    HttpPost post = new HttpPost(url);

    List<NameValuePair> urlParameters = new ArrayList<NameValuePair>();
    urlParameters.add(new BasicNameValuePair("postcodes", "[\"OX49 5NU\", \"M32 0JG\", \"NE30 1DP\"]"));
    post.setEntity(new UrlEncodedFormEntity(urlParameters));
    HttpResponse response = client.execute(post);

    System.out.println("Response Code : " 
                + response.getStatusLine().getStatusCode());
    System.out.println("Reason : " 
            + response.getStatusLine().getReasonPhrase());
    BufferedReader br = new BufferedReader(
            new InputStreamReader(response.getEntity().getContent()));
    StringBuffer result = new StringBuffer();
    String line = "";
    while ((line = br.readLine()) != null) {
        result.append(line);
    }
    br.close();
    System.out.println(result.toString());
}

Answer 1

这有效，HTTP.UTF_8 已弃用:

String url = "http://api.postcodes.io/postcodes";
HttpClient client = HttpClientBuilder.create().build();
HttpPost post = new HttpPost(url);

StringEntity params =new StringEntity("{\"postcodes\" : [\"OX49 5NU\", \"M32 0JG\", \"NE30 1DP\"]}");
post.addHeader("Content-Type", "application/json");
post.setEntity(params);