类文件

注意由于交给连接池管理HttpClient了,所以我们在doGet方法中不要自己关闭HttpClient

package cn.itcast.crawler.test;

import org.apache.hc.client5.http.classic.methods.HttpGet;
import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse;
import org.apache.hc.client5.http.impl.classic.HttpClients;
import org.apache.hc.client5.http.impl.io.PoolingHttpClientConnectionManager;
import org.apache.hc.core5.http.io.entity.EntityUtils;

import javax.swing.text.html.parser.Entity;
import java.io.IOException;

public class HttpClientPoolTest {
    public static void main(String[] args) {
        //创建连接池管理器
        PoolingHttpClientConnectionManager cm=new PoolingHttpClientConnectionManager();

        //设置最大连接数
        cm.setMaxTotal(100);

        //设置每个主机的最大连接数
        cm.setDefaultMaxPerRoute(10);

        //使用连接池管理器发起请求
        doGet(cm);
        //doPost(cm);
        //
    }

    private static void doGet(PoolingHttpClientConnectionManager cm) {
        //不是每次创建新的HttpCLient,而是从连接池中获取HttpClient对象
        CloseableHttpClient httpClient = HttpClients.custom().setConnectionManager(cm).build();

        HttpGet httpGet=new HttpGet("http://www.itcast.cn");

        CloseableHttpResponse response=null;
        try {
            response = httpClient.execute(httpGet);
            if(response.getCode()==200){
                String content = EntityUtils.toString(response.getEntity(), "utf8");
                System.out.println(content.length());
            }
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            if(response!=null){
                try {
                    response.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            //不能关闭httpclient,由连接池管理httpclient
            //httpClient.close();
        }
    }
}