Java 8与apache httpClient 4

CloseableHttpClient client = HttpClientBuilder.create().build();
HttpPost httpPost = new HttpPost("www.site.com");


String json = "details={\"name\":\"myname\",\"age\":\"20\"} ";

        try {
            StringEntity entity = new StringEntity(json);
            httpPost.setEntity(entity);

            // set your POST request headers to accept json contents
            httpPost.setHeader("Accept", "application/json");
            httpPost.setHeader("Content-type", "application/json");

            try {
                // your closeablehttp response
                CloseableHttpResponse response = client.execute(httpPost);

                // print your status code from the response
                System.out.println(response.getStatusLine().getStatusCode());

                // take the response body as a json formatted string 
                String responseJSON = EntityUtils.toString(response.getEntity());

                // convert/parse the json formatted string to a json object
                JSONObject jobj = new JSONObject(responseJSON);

                //print your response body that formatted into json
                System.out.println(jobj);

            } catch (IOException e) {
                e.printStackTrace();
            } catch (JSONException e) {

                e.printStackTrace();
            }

        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }

我发现这个问题寻找如何从java客户端发送post请求到谷歌端点的解决方案。以上答案，很可能是正确的，但在谷歌端点的情况下不工作。

谷歌端点的解决方案。

Request body must contains only JSON string, not name=value pair. Content type header must be set to "application/json". post("http://localhost:8888/_ah/api/langapi/v1/createLanguage", "{\"language\":\"russian\", \"description\":\"dsfsdfsdfsdfsd\"}"); public static void post(String url, String json ) throws Exception{ String charset = "UTF-8"; URLConnection connection = new URL(url).openConnection(); connection.setDoOutput(true); // Triggers POST. connection.setRequestProperty("Accept-Charset", charset); connection.setRequestProperty("Content-Type", "application/json;charset=" + charset); try (OutputStream output = connection.getOutputStream()) { output.write(json.getBytes(charset)); } InputStream response = connection.getInputStream(); } It sure can be done using HttpClient as well.

试试下面的代码:

HttpClient httpClient = new DefaultHttpClient();

try {
    HttpPost request = new HttpPost("http://yoururl");
    StringEntity params =new StringEntity("details={\"name\":\"myname\",\"age\":\"20\"} ");
    request.addHeader("content-type", "application/json");
    request.addHeader("Accept","application/json");
    request.setEntity(params);
    HttpResponse response = httpClient.execute(request);

    // handle response here...
}catch (Exception ex) {
    // handle exception here
} finally {
    httpClient.getConnectionManager().shutdown();
}

您可以使用Gson库将java类转换为JSON对象。

为想要发送的变量创建一个pojo类 如上所述

{"name":"myname","age":"20"}

就变成了

class pojo1
{
   String name;
   String age;
   //generate setter and getters
}

一旦在pojo1类中设置了变量，就可以使用下面的代码发送它

String       postUrl       = "www.site.com";// put in your url
Gson         gson          = new Gson();
HttpClient   httpClient    = HttpClientBuilder.create().build();
HttpPost     post          = new HttpPost(postUrl);
StringEntity postingString = new StringEntity(gson.toJson(pojo1));//gson.tojson() converts your pojo to json
post.setEntity(postingString);
post.setHeader("Content-type", "application/json");
HttpResponse  response = httpClient.execute(post);

这些是进口

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.HttpClientBuilder;

和GSON

import com.google.gson.Gson;

@momo对Apache HttpClient的回答，4.3.1版本或更高版本。我使用JSON- java构建我的JSON对象:

JSONObject json = new JSONObject();
json.put("someKey", "someValue");    

CloseableHttpClient httpClient = HttpClientBuilder.create().build();

try {
    HttpPost request = new HttpPost("http://yoururl");
    StringEntity params = new StringEntity(json.toString());
    request.addHeader("content-type", "application/json");
    request.setEntity(params);
    httpClient.execute(request);
// handle response here...
} catch (Exception ex) {
    // handle exception here
} finally {
    httpClient.close();
}

对于Java 11，你可以使用新的HTTP客户端:

HttpClient client = HttpClient.newHttpClient();
HttpRequest request = HttpRequest.newBuilder()
    .uri(URI.create("http://localhost/api"))
    .header("Content-Type", "application/json")
    .POST(ofInputStream(() -> getClass().getResourceAsStream(
        "/some-data.json")))
    .build();

client.sendAsync(request, BodyHandlers.ofString())
    .thenApply(HttpResponse::body)
    .thenAccept(System.out::println)
    .join();

你可以使用InputStream, String, File中的发布者。将JSON转换为字符串或IS可以用Jackson完成。