爬虫：HttpClient Jsoup 爬虫学习

maven工程：

 

 log4j.properties

log4j.rootLogger=DEBUG,A1
log4j.logger.org.example=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.xml

<?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>org.example</groupId>
    <artifactId>com.mwq.webmagic</artifactId>
    <version>1.0-SNAPSHOT</version>
    <dependencies>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.5.2</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-log4j12 -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.7.25</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.jsoup/jsoup -->
        <dependency>
            <groupId>org.jsoup</groupId>
            <artifactId>jsoup</artifactId>
            <version>1.10.2</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/junit/junit -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
        <!-- https://mvnrepository.com/artifact/commons-io/commons-io -->
        <dependency>
            <groupId>commons-io</groupId>
            <artifactId>commons-io</artifactId>
            <version>2.6</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.apache.commons/commons-lang3 -->
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>3.7</version>
        </dependency>


    </dependencies>



</project>

一、HttpClient模拟浏览器请求网页

package com.mwq.crawler.test;

import org.apache.http.HttpEntity;
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;

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

        //输入网址，发起GET请求创建HttpGet对象
        HttpGet httpGet = new HttpGet("http://www.itcast.cn");

        //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);

        if(response.getStatusLine().getStatusCode() == 200){
            HttpEntity httpEntity = response.getEntity();
            String content = EntityUtils.toString(httpEntity,"utf-8");

            System.out.println(content);
        }

    }
}

二、HttpGet

package com.mwq.crawler.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.util.EntityUtils;

import java.io.IOException;

public class HttpGetTest {
    public static void main(String[] args) {
        //创建httpjclient 对象
        CloseableHttpClient httpClient = HttpClients.createDefault();

        //创建HttpGet对象，设置URL访问地址
        HttpGet httpGet = new HttpGet("http://www.itcast.cn");

        //使用HttpClient发起请求
        CloseableHttpResponse response = null;
        try {
            response = httpClient.execute(httpGet);
            if (response.getStatusLine().getStatusCode() == 200) {
                String content = EntityUtils.toString(response.getEntity());
                System.out.println(content.length());
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            //关闭response
            try {
                response.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                httpClient.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }
}

三、带参数的HttpGet

package com.mwq.crawler.test;

import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.utils.URIBuilder;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

import java.io.IOException;
import java.net.URISyntaxException;

public class HttpGetParamTest {
    public static void main(String[] args) throws URISyntaxException {
        //创建httpjclient 对象
        CloseableHttpClient httpClient = HttpClients.createDefault();

        //设置请求地址是：http://yun.itheima.com/search?keys=Java
        //创建urlbuilder
        URIBuilder uriBuilder = new URIBuilder("http://yun.itheima.com/search");
        //设置参数
        uriBuilder.setParameter("keys","Java");
        //创建HttpGet对象，设置URL访问地址
        HttpGet httpGet = new HttpGet(uriBuilder.build());
        System.out.println("发起请求的信息：" + httpGet);
        //使用HttpClient发起请求
        CloseableHttpResponse response = null;
        try {
            response = httpClient.execute(httpGet);
            if (response.getStatusLine().getStatusCode() == 200) {
                String content = EntityUtils.toString(response.getEntity());
                System.out.println(content.length());
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            //关闭response
            try {
                response.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                httpClient.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }
}

四、HttpPost

package com.mwq.crawler.test;

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

import java.io.IOException;

public class HttpPostTest {
    public static void main(String[] args) {
        //创建httpjclient 对象
        CloseableHttpClient httpClient = HttpClients.createDefault();

        //创建HttpGet对象，设置URL访问地址
        HttpPost httpPost = new HttpPost("http://www.itcast.cn");

        //使用HttpClient发起请求
        CloseableHttpResponse response = null;
        try {
            response = httpClient.execute(httpPost);
            if (response.getStatusLine().getStatusCode() == 200) {
                String content = EntityUtils.toString(response.getEntity());
                System.out.println(content.length());
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            //关闭response
            try {
                response.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                httpClient.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }
}

五、带参数的HttpPost

package com.mwq.crawler.test;

import org.apache.http.NameValuePair;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.utils.URIBuilder;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.List;

public class HttpPostParamTest {
    public static void main(String[] args) throws URISyntaxException, Exception {
        //创建httpjclient 对象
        CloseableHttpClient httpClient = HttpClients.createDefault();

        //创建HttpGet对象，设置URL访问地址
        HttpPost httpPost = new HttpPost("http://yun.itheima.com/search");
        //声明LIST稽核，封装表单中的参数
        List<NameValuePair> params  = new ArrayList<NameValuePair>();
        //设置请求地址：http://yun.itheima.com/search?keys=Java
        params.add(new BasicNameValuePair("keys","Java"));
        //设置表单的Entity 对象，第一个参数就是封装号的表单数据，第二个参数就是编码
        UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(params,"utf8");
        httpPost.setEntity(formEntity);
        System.out.println("发起请求的信息：" + httpPost);
        //使用HttpClient发起请求
        CloseableHttpResponse response = null;
        try {
            response = httpClient.execute(httpPost);
            if (response.getStatusLine().getStatusCode() == 200) {
                String content = EntityUtils.toString(response.getEntity());
                System.out.println(content.length());
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            //关闭response
            try {
                response.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                httpClient.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }
}

六、HttpConfig

package com.mwq.crawler.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;

public class HttpConfigTest {
    public static void main(String[] args) {
        //创建httpjclient 对象
        CloseableHttpClient httpClient = HttpClients.createDefault();

        //创建HttpGet对象，设置URL访问地址
        HttpGet httpGet = new HttpGet("http://www.itcast.cn");
            //配置请求信息
        RequestConfig config= RequestConfig.custom().setConnectTimeout(1000) //创建连接的最长时间，单位毫秒
              .setConnectionRequestTimeout(500) //设置获取连接的最长时间，单位是毫秒
              .setSocketTimeout(10*1000) //设置数据传输的最长时间，单位是毫秒
              .build();
        //给请求设置请求信息
        httpGet.setConfig(config);
        //使用HttpClient发起请求
        CloseableHttpResponse response = null;
        try {
            response = httpClient.execute(httpGet);
            if (response.getStatusLine().getStatusCode() == 200) {
                String content = EntityUtils.toString(response.getEntity());
                System.out.println(content.length());
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            //关闭response
            try {
                response.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                httpClient.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }
}

七、HttpClientPool

package com.mwq.crawler.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;

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

        //设置连接最大连接数
        cm.setMaxTotal(100);
        //设置每个主机的最大连接数
        cm.setDefaultMaxPerRoute(10);
        //使用连接池发请求
        doGet(cm);
        doGet(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.getStatusLine().getStatusCode() == 200){
                String content  = EntityUtils.toString(response.getEntity(),"utf8");
                System.out.println(content.length());

            }
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            if(response !=null){
                try {
                    response.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                //不能关闭，由连接池管理

            }
        }
    }

}

八、Jsoup

package jsoup;
/**
 * Jsoup解详文件，一般不用其爬取，因为其对一些技术支持不如httpclient号
 * 最终都是转为dom对象进行解析
 * 解析为元素后可以获取元素中的数据
 * selector查找元素单一方式，组合方式
 */

import org.apache.commons.io.FileUtils;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Attributes;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;
import org.junit.Test;

import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Set;

public class JsoupFirstTest {

        @Test
        public void testUrl()throws Exception{
            //解析URL地址，第一个参数是访问的URL，第二个url是访问超时时间
            Document doc = Jsoup.parse(new URL("http://www.itcast.cn"), 1000);
            //使用 标签选择器，获取title标签中的内容
            String title = doc.getElementsByTag("title").first().text();
            //dayin
            System.out.println(title);
        }
        @Test
        public void testString() throws Exception{
            //使用工具类读取文件，获取字符串
            String content = FileUtils.readFileToString(new File(""),"utf8");
            //解析字符串
            Document doc = Jsoup.parse(content);
            String title = doc.getElementsByTag("title").first().text();
            System.out.println(title);
        }
        @Test
        public void testFile() throws Exception{
            //解析文件
            Document doc = Jsoup.parse(new File(""), "utf8");
            String title = doc.getElementsByTag("title").first().text();
            System.out.println(title);
        }
        @Test
        public  void testDom() throws Exception{
            //解析文件获取document 对象
            Document doc = Jsoup.parse(new File(""), "utf8");
            //根据ID查询元素
            Element element = doc.getElementById("city_di");
            //根据标签获取元素
            Element element1 = doc.getElementsByTag("span").first();
            //根据CLASS获取元素
            Elements el = doc.getElementsByClass("class_a class_b");
            //根据属性获取元素
            Elements abc = doc.getElementsByAttribute("abc");
            Element href = doc.getElementsByAttributeValue("href", "http://sh.itcase.cn").first();
            //打印元素内容
            System.out.println(element.text());
            System.out.println(element1);
            System.out.println(el);
            System.out.println(href);
        }
        @Test
        public void testData() throws Exception{
            //解析文件，获取doc对象
            Document doc = Jsoup.parse(new File(""), "utf8");
            //根据ID获取元素
            Element element=doc.getElementById("test");
            String str = "";
            //从元素中获取数据
            //从元素中获取id
            str = element.id();
            //从元素中获取classname
            str = element.className();
            Set<String> classSet = element.classNames();
            for(String s :classSet){
                System.out.println(s);
            }
            //从元素中获取属性值
           str =  element.attr("id");
            //从元素中获取所有属性
            Attributes attributes = element.attributes();
            System.out.println(attributes.toString());
            //从元素中获取文本内容
            str = element.text();
            System.out.println(str);


        }
        @Test
    public void testSelecter() throws Exception{
            //解析HTML文件，获取dom对象
            Document doc = Jsoup.parse(new File(""), "utf8");
            //通过标签查找元素
//            Elements span = doc.select("span");
//            for (Element element : span) {
//                System.out.println(element.text());
//            }
//            Element element = doc.select("#city_bj").first();
//            System.out.println(element.text());
            //通过class查找元素
            Element e = doc.select(".class_a").first();
            //通过属性查找元素
            Element element = doc.select("[abc]").first();
            //利用属性值查找元素
            Elements elements = doc.select("[class-s_name]");
            for (Element element1 : elements) {
                System.out.println(element1.text());
            }

        }
        @Test
    public void testSelector2()throws Exception{
            //解析HTML文件，获取dom对象
            Document doc = Jsoup.parse(new File(""), "utf8");
            //元素+id
            Element select = doc.select("h3#city_bj").first();
            System.out.println(select.text());
            //元素+class
            select = doc.select("li.class_a").first();
            //元素+属性名
            select = doc.select("span[abc]").first();
            //任意组合
            select = doc.select("span[abc].s_name").first();
            //ancestor child:查找某个元素下子元素，比如：city_con li
            Elements select1 = doc.select(".city_con li");
            for (Element element : select1) {
                System.out.println(element.text());
            }
            //parent > child:查找某个父元素下的直接子元素，如：
            //。city_con > ul >li 查找city_con第一级（直接子元素）的ul，在找所有ul下的第一级Li,ul和Li都是标签
            select1 = doc.select(".city_con > ul >li");
            //parent > *:查找父元素下所有直接子元素
            select1 = doc.select(".city_con > ul >*");
        }

}