Spring遠(yuǎn)程調(diào)用HttpClient/RestTemplate的方法

更新時(shí)間：2021年03月06日 12:13:51 作者：依舊ฅ=ฅ

這篇文章主要介紹了Spring遠(yuǎn)程調(diào)用HttpClient/RestTemplate的方法,本文給大家介紹的非常詳細(xì)，對(duì)大家的學(xué)習(xí)或工作具有一定的參考借鑒價(jià)值，需要的朋友可以參考下

一、HttpClient

兩個(gè)系統(tǒng)間如何互相訪問？兩個(gè)tomcat上的項(xiàng)目如何互相訪問？

采用HttpClient實(shí)現(xiàn)跨系統(tǒng)的接口調(diào)用。

介紹：

官網(wǎng)：http://hc.apache.org/index.html

現(xiàn)在也叫：HttpComponents

HttpClient可以發(fā)送get、post、put、delete、...等請(qǐng)求

使用：

導(dǎo)入坐標(biāo)

<dependency>
  <groupId>org.apache.httpcomponents</groupId>
  <artifactId>httpclient</artifactId>
  <version>4.4</version>
</dependency>

//1、使用HttpClient發(fā)起Get請(qǐng)求
public class DoGET {
 
  public static void main(String[] args) throws Exception {
    // 創(chuàng)建Httpclient對(duì)象,相當(dāng)于打開了瀏覽器
    CloseableHttpClient httpclient = HttpClients.createDefault();
 
    // 創(chuàng)建HttpGet請(qǐng)求，相當(dāng)于在瀏覽器輸入地址
    HttpGet httpGet = new HttpGet("http://www.baidu.com/");
 
    CloseableHttpResponse response = null;
    try {
      // 執(zhí)行請(qǐng)求，相當(dāng)于敲完地址后按下回車。獲取響應(yīng)
      response = httpclient.execute(httpGet);
      // 判斷返回狀態(tài)是否為200
      if (response.getStatusLine().getStatusCode() == 200) {
        // 解析響應(yīng)，獲取數(shù)據(jù)
        String content = EntityUtils.toString(response.getEntity(), "UTF-8");
        System.out.println(content);
      }
    } finally {
      if (response != null) {
        // 關(guān)閉資源
        response.close();
      }
      // 關(guān)閉瀏覽器
      httpclient.close();
    }
 
  }
}
 
 
//2、使用HttpClient發(fā)起帶參數(shù)的Get請(qǐng)求
public class DoGETParam {
 
  public static void main(String[] args) throws Exception {
    // 創(chuàng)建Httpclient對(duì)象
    CloseableHttpClient httpclient = HttpClients.createDefault();
    // 創(chuàng)建URI對(duì)象，并且設(shè)置請(qǐng)求參數(shù)
    URI uri = new URIBuilder("http://www.baidu.com/s").setParameter("wd", "java").build();
    
    // 創(chuàng)建http GET請(qǐng)求
    HttpGet httpGet = new HttpGet(uri);
 
    // HttpGet get = new HttpGet("http://www.baidu.com/s?wd=java");
    
    CloseableHttpResponse response = null;
    try {
      // 執(zhí)行請(qǐng)求
      response = httpclient.execute(httpGet);
      // 判斷返回狀態(tài)是否為200
      if (response.getStatusLine().getStatusCode() == 200) {
        // 解析響應(yīng)數(shù)據(jù)
        String content = EntityUtils.toString(response.getEntity(), "UTF-8");
        System.out.println(content);
      }
    } finally {
      if (response != null) {
        response.close();
      }
      httpclient.close();
    }
  }
}
 
 
//3、使用HttpClient發(fā)起POST請(qǐng)求
public class DoPOST {
  public static void main(String[] args) throws Exception {
    // 創(chuàng)建Httpclient對(duì)象
    CloseableHttpClient httpclient = HttpClients.createDefault();
    // 創(chuàng)建http POST請(qǐng)求
    HttpPost httpPost = new HttpPost("http://www.oschina.net/");
    // 把自己偽裝成瀏覽器。否則開源中國會(huì)攔截訪問
    httpPost.setHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36");
 
    CloseableHttpResponse response = null;
    try {
      // 執(zhí)行請(qǐng)求
      response = httpclient.execute(httpPost);
      // 判斷返回狀態(tài)是否為200
      if (response.getStatusLine().getStatusCode() == 200) {
        // 解析響應(yīng)數(shù)據(jù)
        String content = EntityUtils.toString(response.getEntity(), "UTF-8");
        System.out.println(content);
      }
    } finally {
      if (response != null) {
        response.close();
      }
      // 關(guān)閉瀏覽器
      httpclient.close();
    }
 
  }
}
 
 
//4、使用HttpClient發(fā)起帶有參數(shù)的POST請(qǐng)求
public class DoPOSTParam {
 
  public static void main(String[] args) throws Exception {
    // 創(chuàng)建Httpclient對(duì)象
    CloseableHttpClient httpclient = HttpClients.createDefault();
    // 創(chuàng)建http POST請(qǐng)求，訪問開源中國
    HttpPost httpPost = new HttpPost("http://www.oschina.net/search");
 
    // 根據(jù)開源中國的請(qǐng)求需要，設(shè)置post請(qǐng)求參數(shù)
    List<NameValuePair> parameters = new ArrayList<NameValuePair>(0);
    parameters.add(new BasicNameValuePair("scope", "project"));
    parameters.add(new BasicNameValuePair("q", "java"));
    parameters.add(new BasicNameValuePair("fromerr", "8bDnUWwC"));
    // 構(gòu)造一個(gè)form表單式的實(shí)體
    UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(parameters);
    // 將請(qǐng)求實(shí)體設(shè)置到httpPost對(duì)象中
    httpPost.setEntity(formEntity);
 
    CloseableHttpResponse response = null;
    try {
      // 執(zhí)行請(qǐng)求
      response = httpclient.execute(httpPost);
      // 判斷返回狀態(tài)是否為200
      if (response.getStatusLine().getStatusCode() == 200) {
        // 解析響應(yīng)體
        String content = EntityUtils.toString(response.getEntity(), "UTF-8");
        System.out.println(content);
      }
    } finally {
      if (response != null) {
        response.close();
      }
      // 關(guān)閉瀏覽器
      httpclient.close();
    }
  }
}

二、RestTemplate

RestTemplate是Spring提供的用于訪問Rest服務(wù)的客戶端，RestTemplate提供了多種便捷訪問遠(yuǎn)程Http服務(wù)的方法

HTTP開發(fā)是用apache的HttpClient開發(fā)，代碼復(fù)雜，還得操心資源回收等。代碼很復(fù)雜，冗余代碼多。

導(dǎo)入坐標(biāo)

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-web</artifactId>
</dependency>

創(chuàng)建RestTemplate對(duì)象

@Configuration//加上這個(gè)注解作用，可以被Spring掃描
public class RestTemplateConfig {
  /**
   * 創(chuàng)建RestTemplate對(duì)象，將RestTemplate對(duì)象的生命周期的管理交給Spring
   * @return
   */
  @Bean
  public RestTemplate restTemplate(){
    RestTemplate restTemplate = new RestTemplate();
    //主要解決中文亂碼
    restTemplate.getMessageConverters().set(1, new StringHttpMessageConverter(StandardCharsets.UTF_8));
    return restTemplate;
  }
}

RestTempController

import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.client.RestTemplate;
 
import javax.annotation.Resource;
 
@RestController
@RequestMapping("/consumer")
public class ConsumerController {
  // 從Spring的容器中獲取restTemplate
  @Resource
  private RestTemplate restTemplate;
 
  /**
   * 通過Get請(qǐng)求，保存數(shù)據(jù)
   */
  @GetMapping("/{id}")
  public ResponseEntity<String> findById(@PathVariable Integer id){
    //發(fā)起遠(yuǎn)程請(qǐng)求:通過RestTemplate發(fā)起get請(qǐng)求
    ResponseEntity<String> entity = restTemplate.getForEntity("http://localhost:8090/goods2/1", String.class);
    System.out.println("entity.getStatusCode():"+entity.getStatusCode());
    System.out.println(entity.getBody());
    return entity;
  }
 
  /**
   * 通過Post請(qǐng)求，保存數(shù)據(jù)
   */
  @PostMapping
  public ResponseEntity<String> saveGoods(@RequestBody Goods goods){
    //通過RestTemplate發(fā)起遠(yuǎn)程請(qǐng)求
    /**
     * 第一個(gè)參數(shù)：遠(yuǎn)程地址URI
     * 第二個(gè)參數(shù)：數(shù)據(jù)
     * 第三個(gè)參數(shù)：返回值類型
     */
    ResponseEntity<String> entity = restTemplate.postForEntity("http://localhost:8090/goods2", goods, String.class);
    System.out.println("entity.getStatusCode():"+entity.getStatusCode());
    System.out.println(entity.getBody());
    return entity;
  }
 
  @PutMapping
  public ResponseEntity<String> updateGoods(@RequestBody Goods goods){
    restTemplate.put("http://localhost:8090/goods2",goods);
    return new ResponseEntity<>("修改成功", HttpStatus.OK);
  }
 
  @DeleteMapping("/{id}")
  public ResponseEntity<String> deleteById(@PathVariable Integer id){
    restTemplate.delete("http://localhost:8090/goods2/"+id);
    return new ResponseEntity<>("刪除成功", HttpStatus.OK);
  }
}

只用maven不用springboot框架時(shí)只需要導(dǎo)入依賴到pom文件

<dependency>
  <groupId>org.springframework</groupId>
  <artifactId>spring-web</artifactId>
</dependency>

直接new RestTemplate()對(duì)象使用即可

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