本文参考博客地址为：https://blog.csdn.net/justry_deng/article/details/81042379  

建议先看上面那位老哥的博客再看此文。（上面那篇写的非常详细，我也是根据他的博客完成的，然后又加以优化）

闲话少说直接上代码：

引入相关依赖：（本文会用到这三条）

<!--httpclient引入--><dependency><groupId>org.apache.httpcomponents</groupId><artifactId>httpclient</artifactId><version>4.5.9</version></dependency><!--fastjson--><dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>1.2.47</version></dependency><!-- 支持 @ConfigurationProperties 注解 --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-configuration-processor</artifactId><optional>true</optional></dependency>

创建HttpClientUtil工具类，代码如下：

package com.test.demo;import com.alibaba.fastjson.JSON;
import com.test.demo.model.User;
import org.apache.http.HttpEntity;
import org.apache.http.NameValuePair;
import org.apache.http.ParseException;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.utils.URIBuilder;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.util.EntityUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.List;/*** ClassName:    HttpClientTest* Package:    com.test.demo* Description: httpClient方法封装* Datetime:    2020/1/13   10:45* Author:   zhoukaishun*/
@Component
public class HttpClientUtil {@Autowiredprivate HttpClientConfigure httpClientConfigure;/*** @description GET封装* @author zhoukaishun* @date 2020/1/13 13:12*/public  void doGetHttp(List<NameValuePair> params,Boolean haveParams) {// 获得Http客户端CloseableHttpClient httpClient = HttpClientBuilder.create().build();// 参数URI uri = null;try {// 设置uri信息,并将参数集合放入uri;if(haveParams){//有参调用uri = new URIBuilder().setScheme(httpClientConfigure.getScheme()).setHost(httpClientConfigure.getHost()).setPort(httpClientConfigure.getPort()).setPath(httpClientConfigure.getMapPath().get("interface2")).setParameters(params).build();}else{//无参调用uri = new URIBuilder().setScheme(httpClientConfigure.getScheme()).setHost(httpClientConfigure.getHost()).setPort(httpClientConfigure.getPort()).setPath(httpClientConfigure.getMapPath().get("interface1")).build();}} catch (URISyntaxException e1) {e1.printStackTrace();}// 创建Get请求HttpGet httpGet = new HttpGet(uri);// 响应模型CloseableHttpResponse response = null;try {// 配置信息RequestConfig requestConfig = RequestConfig.custom()// 设置连接超时时间(单位毫秒).setConnectTimeout(5000)// 设置请求超时时间(单位毫秒).setConnectionRequestTimeout(5000)// socket读写超时时间(单位毫秒).setSocketTimeout(5000)// 设置是否允许重定向(默认为true).setRedirectsEnabled(true).build();// 将上面的配置信息 运用到这个Get请求里httpGet.setConfig(requestConfig);// 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());System.out.println("响应内容为:" + EntityUtils.toString(responseEntity));}} 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();}}}/*** @description POST封装* @author zhoukaishun* @date 2020/1/13 14:01*/public  void doPostHttp(User user,Boolean haveParam) {// 获得Http客户端CloseableHttpClient httpClient = HttpClientBuilder.create().build();URI uri = null;try {// 设置uri信息,并将参数集合放入uri;uri = new URIBuilder().setScheme(httpClientConfigure.getScheme()).setHost(httpClientConfigure.getHost()).setPort(httpClientConfigure.getPort()).setPath(haveParam?httpClientConfigure.getMapPath().get("interface4"):httpClientConfigure.getMapPath().get("interface3")).build();} catch (URISyntaxException e1) {e1.printStackTrace();}// 创建Post请求HttpPost httpPost = new HttpPost(uri);if(haveParam){//入参// 利用阿里的fastjson，将Object转换为json字符串;// (需要导入com.alibaba.fastjson.JSON包)String jsonString = JSON.toJSONString(user);StringEntity entity = new StringEntity(jsonString, "UTF-8");// post请求是将参数放在请求体里面传过去的;这里将entity放入post请求体中httpPost.setEntity(entity);httpPost.setHeader("Content-Type", "application/json;charset=utf8");}// 响应模型CloseableHttpResponse response = null;try {// 由客户端执行(发送)Post请求response = httpClient.execute(httpPost);// 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());System.out.println("响应内容为:" + EntityUtils.toString(responseEntity));}} 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();}}}}

其中大部分代码基本不变，只有对url的拼接做了一些处理，可以看到我们注入了一个HttpClientConfigure实例，因为我们需要访问的路径情况有很多种，但是我们不可能每次都去改util下的url拼接代码，所以引入一个HttpClientConfigure，这是我自定义的一个类，用于存储我们拼接url可能遇到的情况。代码如下：

package com.test.demo;import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;import java.util.HashMap;
import java.util.Map;/*** ClassName:    HttpClientConfigure* Package:    com.test.demo* Description: 接收配置信息* Datetime:    2020/1/13   14:41* Author:   zhoukaishun*/
@Component
@ConfigurationProperties(prefix="httpclientconfigure")
@Data
public class HttpClientConfigure {private Map<String, String> mapPath = new HashMap<>();private String scheme;private String host;private Integer port;}

其中的@ConfigurationProperties注解 前面提到过，在pom中，其中属性值配置在yml文件中，如下（具体内容根据自己的需求来定）：

到这里就可以开始测试了，可以在本地启动两个服务（一个服务也行），根据自己controller里面的访问路径配置httpclientconfigure,然后直接调用自己controller里方法即可。

以我的demo为例，调用者controller代码如下：

@GetMapping@RequestMapping("/doGetHaveNoParam")public void doGetHaveNoParam(){httpClientUtil.doGetHttp(null,false);}@GetMapping@RequestMapping("/doGetHaveParam")public void doGetHaveParam(){System.out.println("调用有参Get请求，当前时间："+System.currentTimeMillis());List<NameValuePair> params = new ArrayList<>();params.add(new BasicNameValuePair("name", "&"));params.add(new BasicNameValuePair("age", "22"));httpClientUtil.doGetHttp(params,true);}@PostMapping@RequestMapping("/doPostHaveNoParam")public void doPostHaveNoParam(){httpClientUtil.doPostHttp(null,false);}@PostMapping@RequestMapping("/doPostHaveParam")public void doPostHaveParam(){httpClientUtil.doPostHttp(new User("name",11),true);}

被调用者controller代码如下：

    @RequestMapping("/doGetHaveNoParam")public String doGetHaveNoParam(){return "doGetHaveNoParam successful";}@RequestMapping("/doGetHaveParam")public List<User> doGetHaveParam(String name,Integer age){return getUserByAge(name,age);}@PostMapping@RequestMapping("/doPostHaveNoParam")public String doPostHaveNoParam(){return "doPostHaveNoParam successful";}@PostMapping@RequestMapping("/doPostHaveParam")public String doHttpPostParam(@RequestBody User user){return "do Post params:name="+user.getName()+",age="+user.getAge();

使用postman测试如下：

请求路径分别为：

http://localhost:8081/user/doGetHaveNoParam

http://localhost:8081/user/doGetHaveParam

http://localhost:8081/user/doPostHaveNoParam

http://localhost:8081/user/doPostHaveParam

响应结果如下：

至此结束，如若对你有帮助点个赞呗。