springboot中RestTemplate和okhttp以及HttpClient对比的示例分析

springboot中RestTemplate和okhttp以及HttpClient对比的示例分析，很多新手对此不是很清楚，为了帮助大家解决这个难题，下面小编将为大家详细讲解，有这方面需求的人可以来学习下，希望你能有所收获。

1、HttpClient：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。

2、RestTemplate： 是 Spring 提供的用于访问Rest服务的客户端， RestTemplate 提供了多种便捷访问远程Http服务的方法,能够大大提高客户端的编写效率。

引入jar包：

              org.springframework.boot            spring-boot-starter-web        

添加初始化配置（也可以不配，有默认的）--注意RestTemplate只有初始化配置，没有什么连接池

package com.itunion.config;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.http.client.ClientHttpRequestFactory;import org.springframework.http.client.SimpleClientHttpRequestFactory;import org.springframework.web.client.RestTemplate;@Configurationpublic class ApiConfig {    @Bean    public RestTemplate restTemplate(ClientHttpRequestFactory factory) {        return new RestTemplate(factory);    }    @Bean    public ClientHttpRequestFactory simpleClientHttpRequestFactory() {        SimpleClientHttpRequestFactory factory = new SimpleClientHttpRequestFactory();//默认的是JDK提供http连接，需要的话可以//通过setRequestFactory方法替换为例如Apache HttpComponents、Netty或//OkHttp等其它HTTP library。        factory.setReadTimeout(5000);//单位为ms        factory.setConnectTimeout(5000);//单位为ms        return factory;    }}

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

　　2）post请求：

// 1-postForObject()User user1 = this.restTemplate.postForObject(uri, user, User.class);// 2-postForEntity()ResponseEntity responseEntity1 = this.restTemplate.postForEntity(uri, user, User.class);// 3-exchange()RequestEntity requestEntity = RequestEntity.post(new URI(uri)).body(user);ResponseEntity 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 entity = new HttpEntity(requestJson,headers);        String result = restTemplate.postForObject(url, entity, String.class);        System.out.println(result);

　　方式二：

@Testpublic 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 map= new LinkedMultiValueMap<>();    map.add("email", "844072586@qq.com");     HttpEntity> request = new HttpEntity<>(map, headers);    ResponseEntity response = restTemplate.postForEntity( url, request , String.class );    System.out.println(response.getBody());}

其它：还支持上传和下载功能；

3、okhttp：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。

1）使用：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。

引入jar包：

    com.squareup.okhttp3    okhttp    3.10.0

2）配置文件：

import okhttp3.ConnectionPool;import okhttp3.OkHttpClient;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import javax.net.ssl.SSLContext;import javax.net.ssl.SSLSocketFactory;import javax.net.ssl.TrustManager;import javax.net.ssl.X509TrustManager;import java.security.KeyManagementException;import java.security.NoSuchAlgorithmException;import java.security.SecureRandom;import java.security.cert.CertificateException;import java.security.cert.X509Certificate;import java.util.concurrent.TimeUnit;@Configurationpublic class OkHttpConfiguration {    @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);    }}

3）util工具：

import okhttp3.*;import org.apache.commons.lang3.exception.ExceptionUtils;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import java.io.File;import java.util.Iterator;import java.util.Map;public class OkHttpUtil{    private static final Logger logger = LoggerFactory.getLogger(OkHttpUtil.class);        private static OkHttpClient  okHttpClient;    @Autowired    public OkHttpUtil(OkHttpClient  okHttpClient) {        OkHttpUtil.okHttpClient= okHttpClient;    }         /**     * get     * @param url     请求的url     * @param queries 请求的参数，在浏览器？后面的数据，没有可以传null     * @return     */    public static  String get(String url, Map queries) {        String responseBody = "";        StringBuffer sb = new StringBuffer(url);        if (queries != null && queries.keySet().size() > 0) {            boolean firstFlag = true;            Iterator iterator = queries.entrySet().iterator();            while (iterator.hasNext()) {                Map.Entry entry = (Map.Entry) iterator.next();                if (firstFlag) {                    sb.append("?" + entry.getKey() + "=" + entry.getValue());                    firstFlag = false;                } else {                    sb.append("&" + entry.getKey() + "=" + entry.getValue());                }            }        }        Request request = new Request.Builder()                .url(sb.toString())                .build();        Response response = null;        try {             response = okHttpClient.newCall(request).execute();            int status = response.code();            if (response.isSuccessful()) {                return response.body().string();            }        } catch (Exception e) {            logger.error("okhttp3 put error >> ex = {}", ExceptionUtils.getStackTrace(e));        } finally {            if (response != null) {                response.close();            }        }        return responseBody;    }    /**     * post     *     * @param url    请求的url     * @param params post form 提交的参数     * @return     */    public static String post(String url, Map params) {        String responseBody = "";        FormBody.Builder builder = new FormBody.Builder();        //添加参数        if (params != null && params.keySet().size() > 0) {            for (String key : params.keySet()) {                builder.add(key, params.get(key));            }        }        Request request = new Request.Builder()                .url(url)                .post(builder.build())                .build();        Response response = null;        try {             response = okHttpClient.newCall(request).execute();            int status = response.code();            if (response.isSuccessful()) {                return response.body().string();            }        } catch (Exception e) {            logger.error("okhttp3 post error >> ex = {}", ExceptionUtils.getStackTrace(e));        } finally {            if (response != null) {                response.close();            }        }        return responseBody;    }    /**     * get     * @param url     请求的url     * @param queries 请求的参数，在浏览器？后面的数据，没有可以传null     * @return     */    public static String getForHeader(String url, Map queries) {        String responseBody = "";        StringBuffer sb = new StringBuffer(url);        if (queries != null && queries.keySet().size() > 0) {            boolean firstFlag = true;            Iterator iterator = queries.entrySet().iterator();            while (iterator.hasNext()) {                Map.Entry entry = (Map.Entry) iterator.next();                if (firstFlag) {                    sb.append("?" + entry.getKey() + "=" + entry.getValue());                    firstFlag = false;                } else {                    sb.append("&" + entry.getKey() + "=" + entry.getValue());                }            }        }        Request request = new Request.Builder()                .addHeader("key", "value")                .url(sb.toString())                .build();        Response response = null;        try {             response = okHttpClient.newCall(request).execute();            int status = response.code();            if (response.isSuccessful()) {                return response.body().string();            }        } catch (Exception e) {            logger.error("okhttp3 put error >> ex = {}", ExceptionUtils.getStackTrace(e));        } finally {            if (response != null) {                response.close();            }        }        return responseBody;    }    /**     * Post请求发送JSON数据....{"name":"zhangsan","pwd":"123456"}     * 参数一：请求Url     * 参数二：请求的JSON     * 参数三：请求回调     */    public static String postJsonParams(String url, String jsonParams) {        String responseBody = "";        RequestBody requestBody = RequestBody.create(MediaType.parse("application/json; charset=utf-8"), jsonParams);        Request request = new Request.Builder()                .url(url)                .post(requestBody)                .build();        Response response = null;        try {             response = okHttpClient.newCall(request).execute();            int status = response.code();            if (response.isSuccessful()) {                return response.body().string();            }        } catch (Exception e) {            logger.error("okhttp3 post error >> ex = {}", ExceptionUtils.getStackTrace(e));        } finally {            if (response != null) {                response.close();            }        }        return responseBody;    }    /**     * Post请求发送xml数据....     * 参数一：请求Url     * 参数二：请求的xmlString     * 参数三：请求回调     */    public static String postXmlParams(String url, String xml) {        String responseBody = "";        RequestBody requestBody = RequestBody.create(MediaType.parse("application/xml; charset=utf-8"), xml);        Request request = new Request.Builder()                .url(url)                .post(requestBody)                .build();        Response response = null;        try {             response = okHttpClient.newCall(request).execute();            int status = response.code();            if (response.isSuccessful()) {                return response.body().string();            }        } catch (Exception e) {            logger.error("okhttp3 post error >> ex = {}", ExceptionUtils.getStackTrace(e));        } finally {            if (response != null) {                response.close();            }        }        return responseBody;    }}

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