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类文件

package cn.itcast.crawler.test;

import org.apache.hc.client5.http.classic.HttpClient;
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.core5.http.HttpEntity;
import org.apache.hc.core5.http.io.entity.EntityUtils;

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

public class CrawlerFirst {
    public static void main(String[] args) throws Exception {
        //1.打开浏览器,创建HttpClient对象
        CloseableHttpClient httpClient = HttpClients.createDefault();

        //2.访问网址,发起get请求创建HttpGet对象
        HttpGet httpGet = new HttpGet("http://www.itcast.cn");

        //3.按回车,发起请求,返回响应,使用HttpClient对象发起请求
        CloseableHttpResponse response = httpClient.execute(httpGet);

        //4.解析响应,获取数据
        //判断状态码是否是200
        if(response.getCode()==200){
            HttpEntity httpEntity = response.getEntity();
            String content = EntityUtils.toString(httpEntity, "utf-8");
            System.out.println(content);
        }

    }
}

log4j配置文件 log4j.properties

log4j.rootLogger=DEBUG,A1
log4j.logger.cn.itcast = DEBUG
log4j.appender.A1=org.apache.log4j.ConsoleAppender
log4j.appender.A1.layout=org.apache.log4j.PatternLayout
log4j.appender.A1.layout.ConversionPattern=%-d{yyyy-MM-dd HH:mm:ss, SSS} ?%t? ?%c?-?%p? %m%n

pom配置文件

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>cn.itcast</groupId>
    <artifactId>itcast-crawler-first</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>

    <!-- https://mvnrepository.com/artifact/org.apache.httpcomponents.client5/httpclient5 -->
    <dependency>
        <groupId>org.apache.httpcomponents.client5</groupId>
        <artifactId>httpclient5</artifactId>
        <version>5.2.1</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-log4j12 -->
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-log4j12</artifactId>
        <version>1.7.25</version>
<!--        <scope>test</scope>-->
    </dependency>

    </dependencies>
</project>