HttpClient使用简单例子

依赖：

<dependency>
  <groupId>org.apache.httpcomponents</groupId>
 <artifactId>httpcore</artifactId>
 <!--<version>4.4.10</version>-->
</dependency>

<dependency>
 <groupId>org.apache.httpcomponents</groupId>
 <artifactId>httpclient</artifactId>
 <!--<version>4.5.6</version>-->
</dependency>

package org.example.util;

import org.apache.http.HttpEntity;
import org.apache.http.ParseException;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.util.EntityUtils;
import org.springframework.stereotype.Component;

import java.io.IOException;

@Component
public class HttpClientUtil {

 public String get(String req){
 CloseableHttpClient httpClient = HttpClientBuilder.create().build();
 // 创建Get请求
 HttpGet httpGet = new HttpGet("http://localhost:8088/getString");
 httpGet.addHeader("req",req);
 // 响应模型
 CloseableHttpResponse response = null;
 try {
 // 由客户端执行(发送)Get请求
 response = httpClient.execute(httpGet);
 // 从响应模型中获取响应实体
 HttpEntity responseEntity = response.getEntity();
 System.out.println("响应状态为:" + response.getStatusLine());
 if (responseEntity != null) {
 System.out.println("响应内容长度为:" + responseEntity.getContentLength());
 String returnstr = EntityUtils.toString(responseEntity);
 System.out.println("响应内容为:" + returnstr);
 return returnstr;
 }
 } catch (ClientProtocolException e) {
 e.printStackTrace();
 } catch (ParseException e) {
 e.printStackTrace();
 } catch (IOException e) {
 e.printStackTrace();
 } finally {
 try {
 // 释放资源
 if (httpClient != null) {
 httpClient.close();
 }
 if (response != null) {
 response.close();
 }
 } catch (IOException e) {
 e.printStackTrace();
 }
 }
 return null;
 }
}