apache HttpClient

 

mport org.apache.http.*;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.ResponseHandler;
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.BasicHeader;
import org.apache.http.protocol.HttpContext;
import org.apache.http.util.EntityUtils;

import java.io.IOException;
import java.util.Scanner;

public class HCL {
    public static void main(String[] args) {
        try {
//            doPost();
//            doGet();
//            doGetWithHandle();
//            doGetWithabort();
            clientWithInterceptor();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

    public static void doPost() throws IOException {
//Creating a HttpClient object
        CloseableHttpClient httpclient = HttpClients.createDefault();
        try {
            //Creating a HttpGet object
            HttpPost httppost = new HttpPost("http://www.baidu.com/");

            //Printing the method used
            System.out.println("Request Type: " + httppost.getMethod());

            //Executing the Get request
            HttpResponse httpresponse = httpclient.execute(httppost);

            Scanner sc = new Scanner(httpresponse.getEntity().getContent());

            //Printing the status line
            System.out.println(httpresponse.getStatusLine());
            while (sc.hasNext()) {
                System.out.println(sc.nextLine());
            }

        } finally {
            httpclient.close();
        }


    }

    public static void doGet() throws IOException {
        CloseableHttpClient httpclient = HttpClients.createDefault();
        HttpGet httpGet = new HttpGet("http://www.baidu.com");
        HttpResponse httpResponse = httpclient.execute(httpGet);
        Scanner sc = new Scanner(httpResponse.getEntity().getContent());

        //Printing the status line
        System.out.println(httpResponse.getStatusLine());
        while (sc.hasNext()) {
            System.out.println(sc.nextLine());
        }
    }

    public static void doGetWithHandle() throws IOException {
        //Create an HttpClient object
        CloseableHttpClient httpclient = HttpClients.createDefault();

        //Create an HttpGet object
        HttpGet httpget = new HttpGet("http://www.baidu.com/");

        //Execute the Get request by passing the response handler object and HttpGet object
        String httpresponse = httpclient.execute(httpget, new ResponseHandler<String>() {
            @Override
            public String handleResponse(HttpResponse response) throws ClientProtocolException, IOException {
                int status = response.getStatusLine().getStatusCode();
                if (status >= 200 && status < 300) {
                    HttpEntity entity = response.getEntity();
                    if(entity == null){
                        return "";
                    }else{
                        return EntityUtils.toString(entity);
                    }
                }else{
                    return ""+status;
                }
            }
        });
        System.out.println(httpresponse);
    }

    public static void doGetWithabort() throws IOException {
        //Creating an HttpClient object
        CloseableHttpClient httpclient = HttpClients.createDefault();

        //Creating an HttpGet object
        HttpGet httpget = new HttpGet("http://www.kaops.com/");

        //Printing the method used
        System.out.println(httpget.getMethod());

        //Executing the Get request
        HttpResponse httpresponse = httpclient.execute(httpget);

        //Printing the status line
        System.out.println(httpresponse.getStatusLine());

        httpget.abort();
        System.out.println(httpresponse.getEntity().getContentLength());

        //Executing the Get request
        HttpResponse httpresponse2 = httpclient.execute(httpget);
        System.out.println(httpresponse2.getStatusLine());
    }

    public static void clientWithInterceptor() throws IOException {
        CloseableHttpClient httpclient =
                HttpClients.custom().addInterceptorFirst(new HttpRequestInterceptor() {
                    @Override
                    public void process(HttpRequest request, HttpContext httpContext) throws HttpException, IOException {
                        if (request.containsHeader("sample-header")) {
                            System.out.println("Contains header sample-header, removing it..");
                            request.removeHeaders("sample-header");
                        }
                        //Printing remaining list of headers
                        Header[] headers = request.getAllHeaders();
                        for (int i = 0; i < headers.length; i++) {
                            System.out.println(headers[i].getName());
                        }
                    }
                }).build();

        //Creating a request object
        HttpGet httpget1 = new HttpGet("https://www.kaops.com/");

        //Setting the header to it
        httpget1.setHeader(new BasicHeader("sample-header","My first header"));
        httpget1.setHeader(new BasicHeader("demo-header","My second header"));
        httpget1.setHeader(new BasicHeader("test-header","My third header"));

        //Executing the request
        HttpResponse httpresponse = httpclient.execute(httpget1);

        //Printing the status line
        System.out.println(httpresponse.getStatusLine());


    }