HttpURLConnection conn = (HttpURLConnection) url.openConnection()

httpUrlConn.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)");

conn.setRequestProperty("User-Agent", "Mozilla/4.76");

不要在java中使用URLConnection，不接受使用 urlConnection 的普通 java 。
訪問(wèn)互聯(lián)網(wǎng).要訪問(wèn)瀏覽器，它需要執(zhí)行搜索，沒(méi)有例外會(huì)導(dǎo)致 
HTTP response code : 403 for URL
但是我本身是使用的HttpURLConnection，并且，如果你使用HttpURLConnection，
應(yīng)該按照我后面的添加setRequestProperty

        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpcore</artifactId>
            <version>4.4.10</version>
        </dependency>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.5.5</version>
        </dependency>

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
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.util.EntityUtils;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;
public class PostClientUtil {
    public static String sendPost(String url,String param){
        OutputStreamWriter out =null;
        BufferedReader reader = null;
        String response = "";

        //創(chuàng)建連接
        try {
            URL httpUrl = null; //HTTP URL類 用這個(gè)類來(lái)創(chuàng)建連接
            //創(chuàng)建URL
            httpUrl = new URL(url);
            //建立連接
            HttpURLConnection conn = (HttpURLConnection) httpUrl.openConnection();
            conn.setRequestMethod("POST");
            conn.setRequestProperty("Content-Type", "application/json");
//            conn.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)");
            conn.setRequestProperty("connection", "keep-alive");
            conn.setRequestProperty("User-Agent", "Mozilla/4.76");
            conn.setUseCaches(false);//設(shè)置不要緩存
            conn.setInstanceFollowRedirects(true);
            conn.setDoOutput(true);
            conn.setDoInput(true);
            conn.connect();
            //POST請(qǐng)求
            out = new OutputStreamWriter(
                    conn.getOutputStream());
            out.write(param);
            out.flush();
            //讀取響應(yīng)
            reader = new BufferedReader(new InputStreamReader(
                    conn.getInputStream()));
            String lines;
            while ((lines = reader.readLine()) != null) {
                lines = new String(lines.getBytes(), "utf-8");
                response+=lines;
            }
            reader.close();
            // 斷開(kāi)連接
            conn.disconnect();

        } catch (Exception e) {
            System.out.println("發(fā)送 POST 請(qǐng)求出現(xiàn)異常！"+e);
            e.printStackTrace();
        }
        //使用finally塊來(lái)關(guān)閉輸出流、輸入流
        finally{
            try{
                if(out!=null){
                    out.close();
                }
                if(reader!=null){
                    reader.close();
                }
            }
            catch(IOException ex){
                ex.printStackTrace();
            }
        }

        return response;
    }
}