连接池

java">package cn.lala.crawler.httpclient.test;

import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
import org.apache.http.util.EntityUtils;

import java.io.IOException;


@SuppressWarnings("all")
public class HttpClientPoolManagerTest {
    public static void main(String[] args) throws IOException {
        //创建连接池管理器
        PoolingHttpClientConnectionManager connectionManager = new PoolingHttpClientConnectionManager();

        //设置最大连接数
        connectionManager.setMaxTotal(200);
        //设置每个主机的最大连接数，指定访问每一个网站的连接数，不会影响其他网站的访问
        connectionManager.setDefaultMaxPerRoute(20);
        //使用连接池管理器获取连接并发起请求
        get(connectionManager);
        get(connectionManager);//
    }

    private static void get(PoolingHttpClientConnectionManager connectionManager) throws IOException {
        //使用连接池管理器获取连接
        CloseableHttpClient httpClient = HttpClients.custom().setConnectionManager(connectionManager).build();
        //打印连接，如果两次打印的内存的地址值不一样，证明是不同的连接
        //org.apache.http.impl.client.InternalHttpClient@5af3afd9
        //org.apache.http.impl.client.InternalHttpClient@33f676f6
        System.out.println(httpClient);//
        HttpGet httpGet = new HttpGet("https://www.baidu.com");
        CloseableHttpResponse response = httpClient.execute(httpGet);
        if(response.getStatusLine().getStatusCode()==200){
            String html = EntityUtils.toString(response.getEntity(), "UTF-8");
            System.out.println("请求成功，数据的长度是:"+html.length());
        }
    }
}

设置请求参数

java">package cn.lala.crawler.httpclient.test;

import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

import java.io.IOException;

@SuppressWarnings("all")
public class HttpClientRequestConfigTest {
    public static void main(String[] args) {
        CloseableHttpClient httpClient = HttpClients.createDefault();
        //不带参数的get请求
        HttpGet httpGet = new HttpGet("https://www.baidu.com/"); //创建连接请求参数
        //构建请求配置信息
        RequestConfig config = RequestConfig.custom().setConnectTimeout(1000)//创建连接的最长时间
                .setConnectionRequestTimeout(500)//从连接池获取连接的最长时间
                .setSocketTimeout(10 * 1000)//设置传输数据的最长时间
                .build();
        //把请求参数设置到httpGet中
        httpGet.setConfig(config);
        CloseableHttpResponse response = null;
        try {
            response = httpClient.execute(httpGet);

            if (response.getStatusLine().getStatusCode() == 200) {
                String html = EntityUtils.toString(response.getEntity(), "UTF-8");
                System.out.println("请求成功，数据的长度是:" + html.length());

            }
        } catch (IOException e) {
            throw new RuntimeException(e);
        } finally {

            if (response != null) {
                try { //关闭response
                    response.close();
                    //关闭httpClient
                    httpClient.close();
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }

        }

    }
}