HttpClient快速入门

野性酷女 2024-02-20 09:00 49阅读 0赞

### HttpClient-基本使用 ###

httpGet和httpPost

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.impl.client.CloseableHttpClient;
    import org.apache.http.impl.client.HttpClients;
    
    import org.apache.http.message.BasicNameValuePair;
    import org.apache.http.util.EntityUtils;
    import org.junit.Test;
    
    import java.io.IOException;
    import java.util.ArrayList;
    
    
    public class HttpClientTest {
        
    
        @Test
        public void testGet() throws IOException {
        
            //1.需要HttpClient对象
            CloseableHttpClient httpClient = HttpClients.createDefault();
            //2.创建HttpGet请求并进行相关设置
            HttpGet httpGet = new HttpGet("https://www.baidu.com/");
            httpGet.setHeader("User-Agent","Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/118.0.0.0 Safari/537.36");
            //3.发起请求
            CloseableHttpResponse response = httpClient.execute(httpGet);
            //4.获取响应数据
            if (response.getStatusLine().getStatusCode() == 200){
         //200表示响应成功
                String html = EntityUtils.toString(response.getEntity(), "UTF-8");
                System.out.println(html);
            }
            //5.关闭资源
            httpClient.close();
            response.close();
        }
    
        @Test
        public void testPost() throws IOException {
        
            //1.需要HttpClient对象
            CloseableHttpClient httpClient = HttpClients.createDefault();
            //2.创建HttpPost请求并进行相关设置
            HttpPost httpPost = new HttpPost("https://www.itcast.cn/");
            //准备集合用来存放参数
            ArrayList<NameValuePair> params = new ArrayList<NameValuePair>();
            params.add(new BasicNameValuePair("username","donglin"));
            UrlEncodedFormEntity entity = new UrlEncodedFormEntity(params, "UTF-8");
            httpPost.setEntity(entity);
            httpPost.setHeader("User-Agent","Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/118.0.0.0 Safari/537.36");
            //3.发起请求
            CloseableHttpResponse response = httpClient.execute(httpPost);
            //4.获取响应数据
            if (response.getStatusLine().getStatusCode() == 200){
         //200表示响应成功
                String html = EntityUtils.toString(response.getEntity(), "UTF-8");
                System.out.println(html);
            }
            //5.关闭资源
            httpClient.close();
            response.close();
        }
    }

### HttpClient-连接池 ###

@Test
        public void testPool() throws IOException {
        
            //1.创建HttpClient连接管理器
            PoolingHttpClientConnectionManager cm = new PoolingHttpClientConnectionManager();
            //2.设置参数
            cm.setMaxTotal(200);  //设置最大连接数
            cm.setDefaultMaxPerRoute(20); //设置每个主机的最大并发
            //调用两次进行试验
            doGet(cm);
            doGet(cm);
        }
    
        private void doGet(PoolingHttpClientConnectionManager cm) throws IOException {
        
            //3.从连接池获取HttpClient对象
            CloseableHttpClient httpClient = HttpClients.custom().setConnectionManager(cm).build();
            //4.创建HttpGet对象
            HttpGet httpGet = new HttpGet("https://www.itcast.cn/");
            //5.发送请求
            CloseableHttpResponse response = httpClient.execute(httpGet);
            //6.获取数据
            if (response.getStatusLine().getStatusCode() == 200){
         //200表示响应成功
                String html = EntityUtils.toString(response.getEntity(), "UTF-8");
                System.out.println(html);
            }
            //7.关闭资源
            response.close();
            //httpClient.close();  //这里不用关闭，因为是连接池
    
        }

### HttpClient-超时设置 & 添加代理 ###

@Test
        public void testConfig() throws IOException {
        
            //0.创建请求配置对象
            RequestConfig requestConfig = RequestConfig.custom()
                    .setSocketTimeout(10000) //设置连接超时时间
                    .setConnectTimeout(10000) //设置创建连接超时时间
                    .setConnectionRequestTimeout(10000) //设置请求超时时间
                    .setProxy(new HttpHost("111.177.63.86",8888))
                    .build();
            //1.创建HttpClient对象
            //CloseableHttpClient httpClient = HttpClients.createDefault();
            CloseableHttpClient httpClient = HttpClients.custom().setDefaultRequestConfig(requestConfig).build();
            //2.创建HttpGet请求并进行相关设置
            HttpGet httpGet = new HttpGet("https://www.itcast.cn/");
            //3.发起请求
            CloseableHttpResponse response = httpClient.execute(httpGet);
            //4.获取响应数据
            if (response.getStatusLine().getStatusCode() == 200){
         //200表示响应成功
                String html = EntityUtils.toString(response.getEntity(), "UTF-8");
                System.out.println(html);
            }
            //5.关闭资源
            httpClient.close();
            response.close();
        }

### HttpClient-封装 ###

import org.apache.http.HttpHost;
    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.impl.conn.PoolingHttpClientConnectionManager;
    import org.apache.http.util.EntityUtils;
    import sun.net.www.http.HttpClient;
    
    import java.io.IOException;
    import java.util.ArrayList;
    import java.util.List;
    import java.util.Random;
    
    public abstract class HttpUtils {
        
    
        private static PoolingHttpClientConnectionManager cm; //声明httpClient管理器对象(连接处)
        private static List<String> userAgentList = null;
        private static RequestConfig config = null;
    
        //静态代码块会在类被夹在的时候执行
        static {
        
            cm = new PoolingHttpClientConnectionManager();
            cm.setMaxTotal(200);
            cm.setDefaultMaxPerRoute(20);
            config = RequestConfig.custom()
                    .setSocketTimeout(10000) //设置连接超时时间
                    .setConnectTimeout(10000) //设置创建连接超时时间
                    .setConnectionRequestTimeout(10000) //设置请求超时时间
                    .setProxy(new HttpHost("111.177.63.86",8888))
                    .build();
            userAgentList = new ArrayList<String>();
            userAgentList.add("Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2227.0 Safari/537.36");
            userAgentList.add("Mozilla/5.0 (Windows NT 6.3; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.90 Safari/537.36");
            userAgentList.add("Mozilla/5.01 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.132 Safari/537.36");
            userAgentList.add("Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E; Shuame)");
            userAgentList.add("Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E; QQBrowser/7.3.8126.400)");
            userAgentList.add("Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E; .NET CLR 1.1.4322)");
            userAgentList.add("Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; Win64; x64; Trident/4.0; .NET CLR 2.0.50727; SLCC2; .NET CLR 3.5.30729; .NET CLR 3.0.30729; .NET4.0C; .NET4.0E; InfoPath.3)");
            userAgentList.add("Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; Win64; x64; Trident/4.0; .NET CLR 2.0.50727; SLCC2; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E)");
            userAgentList.add("Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0");
        }
    
        public static String getHtml(String url){
        
            //1.从连接池中获取httpClient对象
            CloseableHttpClient httpClient = HttpClients.custom().setConnectionManager(cm).build();
            //2.创建HttpGet对象
            HttpGet httpGet = new HttpGet(url);
            //3.设置请求配置对象和请求头
            httpGet.setConfig(config);
            httpGet.setHeader("User-Agent",userAgentList.get(new Random().nextInt(userAgentList.size())));
            //4.发起请求
            CloseableHttpResponse response = null;
            try {
        
                response = httpClient.execute(httpGet);
                //5.获取响应内容
                if (response.getStatusLine().getStatusCode() == 200){
         //200表示响应成功
                    String html = "";
                    if (response.getEntity()!=null){
        
                        html = EntityUtils.toString(response.getEntity(), "UTF-8");
                        System.out.println(html);
                    }
                    return html;
                }
            } catch (IOException e) {
        
                throw new RuntimeException(e);
            }finally {
        
                try {
        
                    response.close();
                } catch (IOException e) {
        
                    throw new RuntimeException(e);
                }
            }
            return null;
        }
    
        public static void main(String[] args) {
        
            HttpUtils.getHtml("https://www.itcast.cn/");
        }
    
    }