Apache HttpClient-Http发布请求

Apache HttpClient是由Apache Software Foundation开发的、采用Java语言的HTTP客户端工具包。它可用于模拟发送HTTP请求并接收HTTP响应，支持HTTP/1.1和HTTP/2协议，可以轻松地创建、发送、接收和处理HTTP请求和响应。

本文将介绍使用Apache HttpClient发布HTTP请求的方法，包括创建HttpClient对象、创建HttpGet或HttpPost对象、设置参数、执行请求等步骤。

Maven引用

在使用Apache HttpClient之前，先确保Maven中已经引入相应的依赖。在pom.xml文件中添加以下依赖：

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.13</version>
</dependency>

发送HTTP GET请求

HTTP GET请求通常用于获取资源，可以通过Apache HttpClient来发送HTTP GET请求。以下是示例代码：

import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

public class HttpGetExample {
    public static void main(String[] args) throws Exception {
        HttpClient httpclient = HttpClients.createDefault();
        HttpGet httpGet = new HttpGet("https://www.example.com");
        httpGet.addHeader("User-Agent", "Mozilla/5.0");
        String responseBody = httpclient.execute(httpGet, response -> EntityUtils.toString(response.getEntity()));
        System.out.println(responseBody);
    }
}

我们首先创建一个HttpClient对象并设置User-Agent头文件，然后创建HttpGet对象并设置URL，最后执行请求并获取响应体。

发送HTTP POST请求

HTTP POST请求通常用于向服务器提交数据，可以通过Apache HttpClient来发送HTTP POST请求。以下是示例代码：

import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

public class HttpPostExample {
    public static void main(String[] args) throws Exception {
        HttpClient httpclient = HttpClients.createDefault();
        HttpPost httpPost = new HttpPost("https://www.example.com");
        httpPost.addHeader("User-Agent", "Mozilla/5.0");
        StringEntity entity = new StringEntity("name=value");
        httpPost.setEntity(entity);
        String responseBody = httpclient.execute(httpPost, response -> EntityUtils.toString(response.getEntity()));
        System.out.println(responseBody);
    }
}

我们首先创建一个HttpClient对象并设置User-Agent头文件，然后创建HttpPost对象并设置URL和请求体，最后执行请求并获取响应体。

设置HTTP客户端参数

在使用Apache HttpClient时，我们可以通过HttpClientBuilder来设置HTTP客户端的参数。以下是示例代码：

import org.apache.http.client.HttpClient;
import org.apache.http.config.SocketConfig;
import org.apache.http.impl.client.HttpClientBuilder;

public class HttpClientConfig {
    public static void main(String[] args) {
        HttpClientBuilder builder = HttpClientBuilder.create();
        SocketConfig socketConfig = SocketConfig.custom()
                .setSoTimeout(10000)
                .build();
        builder.setDefaultSocketConfig(socketConfig);
        HttpClient httpClient = builder.build();
    }
}

我们首先创建一个HttpClientBuilder对象然后设置SocketConfig，最后通过builder.build()方法创建HttpClient对象。

发送HTTP请求并处理响应

使用Apache HttpClient发送HTTP请求后，我们可以获取响应实体并进行处理。以下是示例代码：

import org.apache.http.HttpEntity;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

import java.io.InputStream;

public class HttpEntityExample {
    public static void main(String[] args) throws Exception {
        HttpClient httpclient = HttpClients.createDefault();
        HttpGet httpGet = new HttpGet("https://www.example.com");
        httpGet.addHeader("User-Agent", "Mozilla/5.0");
        HttpEntity httpEntity = httpclient.execute(httpGet).getEntity();
        InputStream inputStream = httpEntity.getContent();
        int bytesRead = 0;
        byte[] buffer = new byte[8192];
        while ((bytesRead = inputStream.read(buffer, 0, 8192)) != -1) {
            // do something with the buffer
        }
        String responseBody = EntityUtils.toString(httpEntity);
        System.out.println(responseBody);
    }
}

我们首先创建一个HttpGet对象并执行请求，然后通过getEntity()方法获取响应实体，通过InputStream读取实体内容，最后通过EntityUtils.toString()方法获取实体字符串。

总结

Apache HttpClient是一个强大的HTTP客户端工具包，可以帮助我们轻松地创建、发送、接收和处理HTTP请求和响应。本文介绍了使用Apache HttpClient发送HTTP GET和POST请求的方法，并提供了设置HTTP客户端参数和处理响应的示例代码。希望这篇文章对您有所帮助。