[网络协议]2021-09-03

Java发送POST请求，并接收返回JSON数据

• 直接上代码

import com.alibaba.fastjson.JSONObject;
import org.apache.http.HttpEntity;
import org.apache.http.ParseException;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicHeader;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.EntityUtils;


import java.io.IOException;
import java.util.HashMap;

public class JsonPost {
    /**
     * 发送post请求
     * @param url  路径
     * @param jsonObject  参数(json类型)
     * @param encoding 编码格式
     * @return
     * @throws ParseException
     * @throws IOException
     */
    public static String send(String url, JSONObject jsonObject, String encoding) throws ParseException, IOException {
        String body = "";

        //创建httpclient对象
        CloseableHttpClient client = HttpClients.createDefault();
        //创建post方式请求对象
        HttpPost httpPost = new HttpPost(url);

        //装填参数
        StringEntity s = new StringEntity(jsonObject.toString(), "utf-8");
        s.setContentEncoding(new BasicHeader(HTTP.CONTENT_TYPE,
                "application/json"));
        //设置参数到请求对象中
        httpPost.setEntity(s);
//        System.out.println("请求地址："+url);
//        System.out.println("请求参数："+nvps.toString());

        //设置header信息
        //指定报文头【Content-type】、【User-Agent】
//        httpPost.setHeader("Content-type", "application/x-www-form-urlencoded");
        httpPost.setHeader("Content-type", "application/json");
        httpPost.setHeader("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)");

        //执行请求操作，并拿到结果（同步阻塞）
        CloseableHttpResponse response = client.execute(httpPost);
        //获取结果实体
        HttpEntity entity = response.getEntity();
        if (entity != null) {
            //按指定编码转换结果实体为String类型
            body = EntityUtils.toString(entity, encoding);
        }
        EntityUtils.consume(entity);
        //释放链接
        response.close();
        return body;
    }

    public static void main(String[] args) throws IOException {
//        将post请求参数写到map中（map中可以存map）
        HashMap<String, String> params = new HashMap<>();
        params.put("date", "20200630");
        params.put("typeId", "dsafa");
        HashMap<String, Object> map = new HashMap<>();
        map.put("key", "42423=q8");
        map.put("id", "42342352");
        map.put("pageNum", "0");
        map.put("pageSize", "1000");
        map.put("params", params);
//        将map转为json对象
        JSONObject json = new JSONObject(map);
        String  url = "http://dc-o.web.leiniao.com/operation/open/request";
        System.out.println(send(url, json, "UTF-8"));
    }
}