Exploring the technical principles of the general framework of the HTTP client in the Java library
Explore the technical principles of the general framework of the HTTP client in the Java library
HTTP is one of the most widely used agreements in modern Internet communication.In Java development, in order to communicate with Web services, we need to use the HTTP client.The Java class library provides many HTTP client frameworks, including some universal frameworks, such as Apache HTTPClient and Java's native HTTPURLCONNECTION.This article will explore the technical principles of these HTTP client universal frameworks and provide the corresponding Java code examples.
1. Apache HttpClient:
Apache HTTPClient is a functional and widely used Java library for handling HTTP requests and responses.It provides high -level functions, such as connection management, status management, certification mechanism, etc.The following is an example code that uses Apache httpclient to send GET requests:
import org.apache.http.HttpResponse;
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;
public class HttpClientExample {
public static void main(String[] args) {
try {
CloseableHttpClient httpClient = HttpClients.createDefault();
HttpGet httpGet = new HttpGet("http://example.com");
HttpResponse response = httpClient.execute(httpGet);
String responseBody = EntityUtils.toString(response.getEntity());
System.out.println(responseBody);
httpClient.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
The above code creates an instance of the default `CloseablehttpClient`, and sends a get request to` http: // example.com`.To obtain the response body through the `response.getitity ()`, and use the `EntityUtils.tostring ()` to convert it to a string output.
2. HttpURLConnection:
Java natively provides `java.net.httpurlConnection` to process HTTP requests and responses.It is simpler than Apache HTTPClient, but it can also meet most HTTP communication needs.The following is an example code that uses HTTPURLCONNECTION to send GET requests:
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
public class HttpURLConnectionExample {
public static void main(String[] args) {
try {
URL url = new URL("http://example.com");
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
String line;
StringBuilder response = new StringBuilder();
while ((line = reader.readLine()) != null) {
response.append(line);
}
reader.close();
connection.disconnect();
System.out.println(response.toString());
} catch (Exception e) {
e.printStackTrace();
}
}
}
The above code sends a GET request to `http: // example.com`.Use `Connection.getInputStream ()` to obtain a response flow, and read and stitch it into string output one by one.
Summarize:
This article explores the technical principles of the use of the general framework of the HTTP client in the Java library.We introduced the two commonly used frameworks, Apache Httpclient and HTTPURLCONNECTION, and provided corresponding code examples.Whether it is a functional Apache Httpclient or a simple and easy -to -use HTTPURLCONNECTION, it can meet most HTTP communication needs.Developers should choose suitable frameworks according to specific needs to achieve communication with Web services.
