使用HttpClient发送Get/Post请求 你get了吗？

HttpClient 是Apache Jakarta Common 下的子项目，可以用来提供高效的、最新的、功能丰富的支持 HTTP 协议的客户端编程工具包，并且它支持 HTTP 协议最新的版本和建议。

1.引入jar包

http://hc.apache.org/downloads.cgi

2.需要一个HttpClientUtils工具类

package cn.happy.util;

import org.apache.http.HttpEntity;
import org.apache.http.HttpHost;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.HttpUriRequest;
import org.apache.http.client.methods.RequestBuilder;
import org.apache.http.conn.routing.HttpRoute;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;

import java.io.IOException;
import java.util.*;

public class HttpClientUtils {

    private static PoolingHttpClientConnectionManager connectionManager = null;
    private static HttpClientBuilder httpBuilder = null;
    private static RequestConfig requestConfig = null;

    private static int MAXCONNECTION = 10;

    private static int DEFAULTMAXCONNECTION = 5;

    private static String IP = "cnivi.com.cn";
    private static int PORT = 80;

    static {
        //设置http的状态参数
        requestConfig = RequestConfig.custom()
                .setSocketTimeout(5000)
                .setConnectTimeout(5000)
                .setConnectionRequestTimeout(5000)
                .build();

        HttpHost target = new HttpHost(IP, PORT);
        connectionManager = new PoolingHttpClientConnectionManager();
        connectionManager.setMaxTotal(MAXCONNECTION);//客户端总并行链接最大数
        connectionManager.setDefaultMaxPerRoute(DEFAULTMAXCONNECTION);//每个主机的最大并行链接数
        connectionManager.setMaxPerRoute(new HttpRoute(target), 20);
        httpBuilder = HttpClients.custom();
        httpBuilder.setConnectionManager(connectionManager);
    }

    public static CloseableHttpClient getConnection() {
        CloseableHttpClient httpClient = httpBuilder.build();
        return httpClient;
    }

    public static HttpUriRequest getRequestMethod(Map<String, String> map, String url, String method) {
        List<NameValuePair> params = new ArrayList<NameValuePair>();
        Set<Map.Entry<String, String>> entrySet = map.entrySet();
        for (Map.Entry<String, String> e : entrySet) {
            String name = e.getKey();
            String value = e.getValue();
            NameValuePair pair = new BasicNameValuePair(name, value);
            params.add(pair);
        }
        HttpUriRequest reqMethod = null;
        if ("post".equals(method)) {
            reqMethod = RequestBuilder.post().setUri(url)
                    .addParameters(params.toArray(new BasicNameValuePair[params.size()]))
                    .setConfig(requestConfig).build();
        } else if ("get".equals(method)) {
            reqMethod = RequestBuilder.get().setUri(url)
                    .addParameters(params.toArray(new BasicNameValuePair[params.size()]))
                    .setConfig(requestConfig).build();
        }
        return reqMethod;
    }

    public static void main(String args[]) throws IOException {
        Map<String, String> map = new HashMap<String, String>();
        map.put("account", "");
        map.put("password", "");

        HttpClient client = getConnection();
        HttpUriRequest post = getRequestMethod(map, "http://cnivi.com.cn/login", "post");
        HttpResponse response = client.execute(post);

        if (response.getStatusLine().getStatusCode() == 200) {
            HttpEntity entity = response.getEntity();
            String message = EntityUtils.toString(entity, "utf-8");
            System.out.println(message);
        } else {
            System.out.println("请求失败");
        }
    }
}

3.发送Get请求

@Test
    public void tGet() throws IOException {
        //创建CloseableHttpClient对象，并为HttpClients赋默认值
        CloseableHttpClient httpClient= HttpClients.createDefault();
        //创建get请求http://www.baidu.com/          http://localhost:8080/isSelectUserto
        HttpGet httpGet=new HttpGet("https://home.cnblogs.com/u/java-263/");
        System.out.println("httpget的请求路径:"+httpGet.getURI());
        //得到响应结果
     CloseableHttpResponse httpResponse=httpClient.execute(httpGet);
     //为HttpEntity创建实体
     HttpEntity httpEntity=httpResponse.getEntity();
     System.out.println("============================");
     //打印响应状态
     System.out.println( httpResponse.getStatusLine());
     if (httpEntity!=null){
         //打印响应内容长度
         System.out.println("entity length:"+httpEntity.getContentLength());
         //打印响应内容
         System.out.println("entity:"+EntityUtils.toString(httpEntity,"UTF-8"));
     }

     httpResponse.close();

     httpClient.close();

 }

4.发送Post请求

@Test
    public void tPost() throws IOException {

     CloseableHttpClient httpClient=HttpClients.createDefault();

     /*=============================POST请求多出的部分内容=================================================*/
     HttpPost httpPost=new HttpPost("http://localhost:8080/isSelectUserto");
    //创建参数队列
     List<NameValuePair> list=new ArrayList<NameValuePair>();
     list.add(new BasicNameValuePair("type","house"));
     UrlEncodedFormEntity encodedFormEntity;
     encodedFormEntity=new UrlEncodedFormEntity(list,"UTF-8");
    /*====================================POST请求多出的部分内容==========================================*/

     httpPost.setEntity(encodedFormEntity);
     System.out.println("URL:"+httpPost.getURI());
 /*    System.out.println("entity length:"+ httpPost.getEntity().getContentLength());*/
    CloseableHttpResponse httpResponse=httpClient.execute(httpPost);
    HttpEntity httpEntity=httpResponse.getEntity();
    if (httpEntity!=null){
        System.out.println("entity length:"+httpEntity.getContentLength());
        System.out.println("Response content: " + EntityUtils.toString(httpEntity, "UTF-8"));
    }

    httpResponse.close();
    httpClient.close();
 }

更多了解参考：https://blog.csdn.net/zhuwukai/article/details/78644484