Http Client 5: Hello World application

Step 1: Get an instance of CloseableHttpClient.

CloseableHttpClient httpClient = HttpClients.createDefault()

Step 2: Create an instance of ClassicHttpRequest.

ClassicHttpRequest request = new HttpGet("https://self-learning-java-tutorial.blogspot.com");

Step 3: Define a response handler.

HttpClientResponseHandler<String> responseHandler = new HttpClientResponseHandler<String>() {
    @Override
    public String handleResponse(final ClassicHttpResponse response) throws IOException, ParseException {

        HttpEntity httpEntity = response.getEntity();

        try (InputStream is = httpEntity.getContent()) {
            return inputStreamToString(is, StandardCharsets.UTF_8);
        }

    }
};

 
Step 4: Execute the request.

String response = httpClient.execute(request, responseHandler);

Find the below working application.

 

HelloWorld.java

package com.sample.app;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.stream.Collectors;

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.HttpClients;
import org.apache.hc.core5.http.ClassicHttpRequest;
import org.apache.hc.core5.http.ClassicHttpResponse;
import org.apache.hc.core5.http.HttpEntity;
import org.apache.hc.core5.http.ParseException;
import org.apache.hc.core5.http.io.HttpClientResponseHandler;

public class HelloWorld {
    public static String inputStreamToString(InputStream inputStream, Charset charSet) throws IOException {

        try (BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, charSet))) {
            return reader.lines().collect(Collectors.joining("\n"));
        }

    }

    public static void main(String[] args) {

        HttpClientResponseHandler<String> responseHandler = new HttpClientResponseHandler<String>() {
            @Override
            public String handleResponse(final ClassicHttpResponse response) throws IOException, ParseException {

                HttpEntity httpEntity = response.getEntity();

                try (InputStream is = httpEntity.getContent()) {
                    return inputStreamToString(is, StandardCharsets.UTF_8);
                }

            }
        };

        try (CloseableHttpClient httpClient = HttpClients.createDefault()) {

            ClassicHttpRequest request = new HttpGet("https://self-learning-java-tutorial.blogspot.com");
            String response = httpClient.execute(request, responseHandler);
            System.out.println(response);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

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