HttpClient、okhttp和RestTemplate的区别

不念不忘少年蓝@ 2022-12-16 09:21 178阅读 0赞

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## 一、HttpClient ##

**1、pom依赖**

<dependency>
        <groupId>commons-httpclient</groupId>
        <artifactId>commons-httpclient</artifactId>
        <version>3.1</version>
    </dependency>

**2、HttpClient代码实现**

public class HttpClientUtil { 
        /** * httpClient的get请求方式 * 使用GetMethod来访问一个URL对应的网页实现步骤： * 1.生成一个HttpClient对象并设置相应的参数； * 2.生成一个GetMethod对象并设置响应的参数； * 3.用HttpClient生成的对象来执行GetMethod生成的Get方法； * 4.处理响应状态码； * 5.若响应正常，处理HTTP响应内容； * 6.释放连接。 * @param url * @param charset * @return */
        public static String doGet(String url, String charset) { 
            //1.生成HttpClient对象并设置参数
            HttpClient httpClient = new HttpClient();
            //设置Http连接超时为5秒
            httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(5000);
            //2.生成GetMethod对象并设置参数
            GetMethod getMethod = new GetMethod(url);
            //设置get请求超时为5秒
            getMethod.getParams().setParameter(HttpMethodParams.SO_TIMEOUT, 5000);
            //设置请求重试处理，用的是默认的重试处理：请求三次
            getMethod.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, new DefaultHttpMethodRetryHandler());
            String response = "";
            //3.执行HTTP GET 请求
            try { 
                int statusCode = httpClient.executeMethod(getMethod);
                //4.判断访问的状态码
                if (statusCode != HttpStatus.SC_OK) { 
                    System.err.println("请求出错：" + getMethod.getStatusLine());
                }
                //5.处理HTTP响应内容
                //HTTP响应头部信息，这里简单打印
                Header[] headers = getMethod.getResponseHeaders();
                for(Header h : headers) { 
                    System.out.println(h.getName() + "---------------" + h.getValue());
                }
                //读取HTTP响应内容，这里简单打印网页内容
                //读取为字节数组
                byte[] responseBody = getMethod.getResponseBody();
                response = new String(responseBody, charset);
                System.out.println("-----------response:" + response);
                //读取为InputStream，在网页内容数据量大时候推荐使用
                //InputStream response = getMethod.getResponseBodyAsStream();
            } catch (HttpException e) { 
                //发生致命的异常，可能是协议不对或者返回的内容有问题
                System.out.println("请检查输入的URL!");
                e.printStackTrace();
            } catch (IOException e) { 
                //发生网络异常
                System.out.println("发生网络异常!");
            } finally { 
                //6.释放连接
                getMethod.releaseConnection();
            }
            return response;
        }
    
        /** * post请求 * @param url * @param json * @return */
        public static String doPost(String url, JSONObject json){ 
            HttpClient httpClient = new HttpClient();
            PostMethod postMethod = new PostMethod(url);
    
            postMethod.addRequestHeader("accept", "*/*");
            postMethod.addRequestHeader("connection", "Keep-Alive");
            //设置json格式传送
            postMethod.addRequestHeader("Content-Type", "application/json;charset=GBK");
            //必须设置下面这个Header
            postMethod.addRequestHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.81 Safari/537.36");
            //添加请求参数
            postMethod.addParameter("commentId", json.getString("commentId"));
    
            String res = "";
            try { 
                int code = httpClient.executeMethod(postMethod);
                if (code == 200){ 
                    res = postMethod.getResponseBodyAsString();
                    System.out.println(res);
                }
            } catch (IOException e) { 
                e.printStackTrace();
            }
            return res;
        }
    
        public static void main(String[] args) { 
            System.out.println(doGet("http://tcc.taobao.com/cc/json/mobile_tel_segment.htm?tel=13026194071", "GBK"));
            System.out.println("-----------分割线------------");
            System.out.println("-----------分割线------------");
            System.out.println("-----------分割线------------");
    
            JSONObject jsonObject = new JSONObject();
            jsonObject.put("commentId", "13026194071");
            System.out.println(doPost("http://tcc.taobao.com/cc/json/mobile_tel_segment.htm?tel=13026194071", jsonObject));
        }
    }

**3、建议**

代码复杂，还得操心资源回收等。代码很复杂，冗余代码多，不建议直接使用。

## 二、okhttp ##

**1、简介**

`OkHttp`是一个高效的`HTTP`客户端，允许所有同一个主机地址的请求共享同一个`socket`连接；连接池减少请求延时；透明的`GZIP`压缩减少响应数据的大小；缓存响应内容，避免一些完全重复的请求

当网络出现问题的时候`OkHttp`依然坚守自己的职责，它会自动恢复一般的连接问题，如果你的服务有多个`IP`地址，当第一个`IP`请求失败时，`OkHttp`会交替尝试你配置的其他`IP`，`OkHttp`使用现代`TLS`技术(`SNI, ALPN`)初始化新的连接，当握手失败时会回退到`TLS 1.0`。

**2、pom依赖**

<dependency>
        <groupId>com.squareup.okhttp3</groupId>
        <artifactId>okhttp</artifactId>
        <version>3.10.0</version>
    </dependency>

它的请求/响应 `API` 使用构造器模式`builders`来设计，它支持`阻塞式的同步`请求和`带回调的异步`请求。

**3、配置文件**

@Configuration
    public class OkHttpConfig { 
        @Bean
        public OkHttpClient okHttpClient() { 
            return new OkHttpClient.Builder()
                    //.sslSocketFactory(sslSocketFactory(), x509TrustManager())
                    .retryOnConnectionFailure(false)
                    .connectionPool(pool())
                    .connectTimeout(30, TimeUnit.SECONDS)
                    .readTimeout(30, TimeUnit.SECONDS)
                    .writeTimeout(30,TimeUnit.SECONDS)
                    .build();
        }
    
        @Bean
        public X509TrustManager x509TrustManager() { 
            return new X509TrustManager() { 
                @Override
                public void checkClientTrusted(X509Certificate[] x509Certificates, String s) throws CertificateException { 
                }
                @Override
                public void checkServerTrusted(X509Certificate[] x509Certificates, String s) throws CertificateException { 
                }
                @Override
                public X509Certificate[] getAcceptedIssuers() { 
                    return new X509Certificate[0];
                }
            };
        }
    
        @Bean
        public SSLSocketFactory sslSocketFactory() { 
            try { 
                //信任任何链接
                SSLContext sslContext = SSLContext.getInstance("TLS");
                sslContext.init(null, new TrustManager[]{ x509TrustManager()}, new SecureRandom());
                return sslContext.getSocketFactory();
            } catch (NoSuchAlgorithmException e) { 
                e.printStackTrace();
            } catch (KeyManagementException e) { 
                e.printStackTrace();
            }
            return null;
        }
    
        /** * Create a new connection pool with tuning parameters appropriate for a single-user application. * The tuning parameters in this pool are subject to change in future OkHttp releases. Currently */
        @Bean
        public ConnectionPool pool() { 
            return new ConnectionPool(200, 5, TimeUnit.MINUTES);
        }
    }

**4、客户端工具**

@Slf4j
    public class OkHttpClient { 
        private static final MediaType JSON = MediaType.parse("application/json; charset=utf-8");
    
        private volatile static okhttp3.OkHttpClient client;
    
        private static final int MAX_IDLE_CONNECTION = Integer
                .parseInt(ConfigManager.get("httpclient.max_idle_connection"));
    
        private static final long KEEP_ALIVE_DURATION = Long
                .parseLong(ConfigManager.get("httpclient.keep_alive_duration"));
    
        private static final long CONNECT_TIMEOUT = Long.parseLong(ConfigManager.get("httpclient.connectTimeout"));
    
        private static final long READ_TIMEOUT = Long.parseLong(ConfigManager.get("httpclient. "));
    
        /** * 单例模式(双重检查模式) 获取类实例 * * @return client */
        private static okhttp3.OkHttpClient getInstance() { 
            if (client == null) { 
                synchronized (okhttp3.OkHttpClient.class) { 
                    if (client == null) { 
                        client = new okhttp3.OkHttpClient.Builder()
                                .connectTimeout(CONNECT_TIMEOUT, TimeUnit.SECONDS)
                                .readTimeout(READ_TIMEOUT, TimeUnit.SECONDS)
                                .connectionPool(new ConnectionPool(MAX_IDLE_CONNECTION, KEEP_ALIVE_DURATION,
                                        TimeUnit.MINUTES))
                                .build();
                    }
                }
            }
            return client;
        }
    
        public static String syncPost(String url, String json) throws IOException { 
            RequestBody body = RequestBody.create(JSON, json);
            Request request = new Request.Builder()
                    .url(url)
                    .post(body)
                    .build();
            try { 
                Response response = OkHttpClient.getInstance().newCall(request).execute();
                if (response.isSuccessful()) { 
                    String result = response.body().string();
                    log.info("syncPost response = {}, responseBody= {}", response, result);
                    return result;
                }
                String result = response.body().string();
                log.info("syncPost response = {}, responseBody= {}", response, result);
                throw new IOException("三方接口返回http状态码为" + response.code());
            } catch (Exception e) { 
                log.error("syncPost() url:{} have a ecxeption {}", url, e);
                throw new RuntimeException("syncPost() have a ecxeption {}" + e.getMessage());
            }
        }
    
        public static String syncGet(String url, Map<String, Object> headParamsMap) throws IOException { 
            Request request;
            final Request.Builder builder = new Request.Builder().url(url);
            try { 
                if (!CollectionUtils.isEmpty(headParamsMap)) { 
                    final Iterator<Map.Entry<String, Object>> iterator = headParamsMap.entrySet()
                            .iterator();
                    while (iterator.hasNext()) { 
                        final Map.Entry<String, Object> entry = iterator.next();
                        builder.addHeader(entry.getKey(), (String) entry.getValue());
                    }
                }
                request = builder.build();
                Response response = OkHttpClient.getInstance().newCall(request).execute();
                String result = response.body().string();
                log.info("syncGet response = {},responseBody= {}", response, result);
                if (!response.isSuccessful()) { 
                    throw new IOException("三方接口返回http状态码为" + response.code());
                }
                return result;
            } catch (Exception e) { 
                log.error("remote interface url:{} have a ecxeption {}", url, e);
                throw new RuntimeException("三方接口返回异常");
            }
        }
    
    }

## 三、RestTemplate ##

1、pom依赖

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

**2、get请求（不带参的即把参数取消即可）**

// 1-getForObject()
    User user1 = this.restTemplate.getForObject(uri, User.class);
    
    // 2-getForEntity()
    ResponseEntity<User> responseEntity1 = this.restTemplate.getForEntity(uri, User.class);
    HttpStatus statusCode = responseEntity1.getStatusCode();
    HttpHeaders header = responseEntity1.getHeaders();
    User user2 = responseEntity1.getBody();
      
    // 3-exchange()
    RequestEntity requestEntity = RequestEntity.get(new URI(uri)).build();
    ResponseEntity<User> responseEntity2 = this.restTemplate.exchange(requestEntity, User.class);
    User user3 = responseEntity2.getBody();

**方式一：**

Notice notice = restTemplate.getForObject("http://fantj.top/notice/list/{1}/{2}"
                    , Notice.class,1,5);

**方式二：**

Map<String,String> map = new HashMap();
    map.put("start","1");
    map.put("page","5");
    Notice notice = restTemplate.getForObject("http://fantj.top/notice/list/"
            , Notice.class,map);

**3、post请求**

// 1-postForObject()
    User user1 = this.restTemplate.postForObject(uri, user, User.class);
    
    // 2-postForEntity()
    ResponseEntity<User> responseEntity1 = this.restTemplate.postForEntity(uri, user, User.class);
    
    // 3-exchange()
    RequestEntity<User> requestEntity = RequestEntity.post(new URI(uri)).body(user);
    ResponseEntity<User> responseEntity2 = this.restTemplate.exchange(requestEntity, User.class);

**方式一：**

String url = "http://demo/api/book/";
    HttpHeaders headers = new HttpHeaders();
    MediaType type = MediaType.parseMediaType("application/json; charset=UTF-8");
    headers.setContentType(type);
    String requestJson = "{...}";
    HttpEntity<String> entity = new HttpEntity<String>(requestJson,headers);
    String result = restTemplate.postForObject(url, entity, String.class);
    System.out.println(result);

**方式二：**

@Test
    public void rtPostObject(){ 
        RestTemplate restTemplate = new RestTemplate();
        String url = "http://47.xxx.xxx.96/register/checkEmail";
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);
        MultiValueMap<String, String> map= new LinkedMultiValueMap<>();
        map.add("email", "844072586@qq.com");
     
        HttpEntity<MultiValueMap<String, String>> request = new HttpEntity<>(map, headers);
        ResponseEntity<String> response = restTemplate.postForEntity( url, request , String.class );
        System.out.println(response.getBody());
    }