HttpClient 发送Post,Get请求例子（包含设置请求头信息和获取返回头信息）

以下是 HttpClient 发送 Post 请求和设置请求头信息的示例：

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;

import java.util.ArrayList;
import java.util.List;

public class HttpClientExample {
    public static void main(String[] args) {
        HttpClient httpClient = HttpClientBuilder.create().build();

        try {
            HttpPost request = new HttpPost("http://www.example.com/api");
            request.setHeader("Content-Type", "application/x-www-form-urlencoded");

            List<NameValuePair> parameters = new ArrayList<>();
            parameters.add(new BasicNameValuePair("key1", "value1"));
            parameters.add(new BasicNameValuePair("key2", "value2"));
            request.setEntity(new UrlEncodedFormEntity(parameters));

            HttpResponse response = httpClient.execute(request);
            HttpEntity entity = response.getEntity();
            String responseText = EntityUtils.toString(entity);
            System.out.println(responseText);

            // 获取返回头信息
            String contentType = response.getFirstHeader("Content-Type").getValue();
            System.out.println(contentType);
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}

以下是 HttpClient 发送 Get 请求和获取返回头信息的示例：

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

public class HttpClientExample {
    public static void main(String[] args) {
        HttpClient httpClient = HttpClientBuilder.create().build();

        try {
            HttpGet request = new HttpGet("http://www.example.com/api");
            request.setHeader("Accept", "application/json");

            HttpResponse response = httpClient.execute(request);
            HttpEntity entity = response.getEntity();
            String responseText = EntityUtils.toString(entity);
            System.out.println(responseText);

            // 获取返回头信息
            String contentType = response.getFirstHeader("Content-Type").getValue();
            System.out.println(contentType);
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}