java调用http接口post请求提交json参数

可以使用Java提供的HttpURLConnection或者Apache HttpClient库来实现POST请求提交JSON参数。

使用HttpURLConnection实现POST请求提交JSON参数的示例代码如下：

import java.net.HttpURLConnection;
import java.net.URL;
import java.io.OutputStream;

public class HttpPostJson {
    public static void main(String[] args) throws Exception {
        String url = "http://example.com/api";
        String json = "{\"username\":\"test\",\"password\":\"123456\"}";

        URL obj = new URL(url);
        HttpURLConnection con = (HttpURLConnection) obj.openConnection();

        // 添加请求头
        con.setRequestMethod("POST");
        con.setRequestProperty("Content-Type", "application/json");

        // 发送POST请求
        con.setDoOutput(true);
        OutputStream os = con.getOutputStream();
        os.write(json.getBytes("UTF-8"));
        os.flush();
        os.close();

        // 获取返回结果
        int responseCode = con.getResponseCode();
        System.out.println("Response Code : " + responseCode);

        BufferedReader in = new BufferedReader(
                new InputStreamReader(con.getInputStream()));
        String inputLine;
        StringBuffer response = new StringBuffer();

        while ((inputLine = in.readLine()) != null) {
            response.append(inputLine);
        }
        in.close();

        // 打印返回结果
        System.out.println(response.toString());
    }
}

使用Apache HttpClient库实现POST请求提交JSON参数的示例代码如下：

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;
import org.apache.http.HttpResponse;
import java.io.BufferedReader;
import java.io.InputStreamReader;

public class HttpPostJson {
    public static void main(String[] args) throws Exception {
        String url = "http://example.com/api";
        String json = "{\"username\":\"test\",\"password\":\"123456\"}";

        HttpClient httpClient = HttpClientBuilder.create().build();
        HttpPost request = new HttpPost(url);

        // 设置请求头
        request.setHeader("Content-Type", "application/json");

        // 设置请求参数
        StringEntity params = new StringEntity(json);
        request.setEntity(params);

        // 发送POST请求
        HttpResponse response = httpClient.execute(request);

        // 获取返回结果
        BufferedReader rd = new BufferedReader(
                new InputStreamReader(response.getEntity().getContent()));

        StringBuffer result = new StringBuffer();
        String line = "";
        while ((line = rd.readLine()) != null) {
            result.append(line);
        }

        // 打印返回结果
        System.out.println(result.toString());
    }
}

以上示例代码仅供参考，实际使用时需要根据自己的需求进行修改。