使用RestTemplate封装post请求
之前笔者写过一篇比较实用的文章 java使用httpclient封装post请求和get的请求，其实java中实现http请求还可以用 RestTemplate 完成，下面给出示例代码：
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import com.alibaba.fastjson.JSONObject;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.http.*;import org.springframework.http.converter.StringHttpMessageConverter;import org.springframework.web.client.RestTemplate;import javax.annotation.PostConstruct;import java.nio.charset.Charset;public class HttpHelper { private static Logger logger = LoggerFactory.getLogger(HttpHelper.class); private RestTemplate restTemplate; private HttpHeaders httpHeaders; @PostConstruct public void init() { restTemplate = new RestTemplate(); restTemplate.getMessageConverters().add(0, new StringHttpMessageConverter(Charset.forName("UTF-8"))); httpHeaders = new HttpHeaders(); httpHeaders.setContentType(org.springframework.http.MediaType.APPLICATION_JSON); } /** * post - json * @param params * @return */ public String post(JSONObject params, String url) { logger.info("请求参数：{}", params.toJSONString()); ResponseEntity<String> response; try { response = restTemplate.exchange( url, HttpMethod.POST, new HttpEntity<>(params, httpHeaders), String.class); } catch (Exception e) { logger.error("请求异常", e); return "请求异常"; } logger.info("响应结果：{}", JSONObject.toJSONString(response)); if (response.getStatusCode().equals(HttpStatus.OK)) { logger.info("请求成功，返回结果：{}", response.getBody()); return response.getBody(); } logger.error("请求失败，Http状态码：{}，返回结果：{}", response.getStatusCode(), response.getBody()); return response.getBody(); }} |
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。
RestTemplate使用封装
之前接口调用习惯性使用HttpClient，代码复杂，冗余代码多，关心资源回收用起来不是很爽。
RestTemplate默认依赖jdk的HTTP连接工具。也可以 通过setRequestFactory属性切换到不同的HTTP源，比如Apache HttpComponents、Netty、OkHttp。
1、SpringBoot使用RestTemplate(使用apache的httpclient)
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import org.springframework.boot.web.client.RestTemplateBuilder;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.http.client.ClientHttpRequestFactory;import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;import org.springframework.http.converter.ByteArrayHttpMessageConverter;import org.springframework.http.converter.FormHttpMessageConverter;import org.springframework.http.converter.HttpMessageConverter;import org.springframework.http.converter.ResourceHttpMessageConverter;import org.springframework.http.converter.StringHttpMessageConverter;import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;import org.springframework.http.converter.support.AllEncompassingFormHttpMessageConverter;import org.springframework.web.client.RestTemplate;import java.nio.charset.Charset;import java.text.SimpleDateFormat;import java.util.ArrayList;import java.util.List;import java.util.concurrent.TimeUnit;@Configurationpublic class RestTemplateConfig { @Bean public RestTemplate getRestTemplate() { //手动指定转换器(HttpMessageConverter) List<HttpMessageConverter<?>> messageConverters = new ArrayList<HttpMessageConverter<?>>(); messageConverters.add(new ByteArrayHttpMessageConverter()); messageConverters.add(new StringHttpMessageConverter(Charset.forName("UTF-8")));//string强制使用UTF-8 messageConverters.add(new ResourceHttpMessageConverter()); messageConverters.add(new AllEncompassingFormHttpMessageConverter()); messageConverters.add(new FormHttpMessageConverter()); MappingJackson2HttpMessageConverter jacksonConverter = new MappingJackson2HttpMessageConverter(); jacksonConverter.getObjectMapper().setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")); messageConverters.add(jacksonConverter); RestTemplate restTemplate = new RestTemplateBuilder().additionalMessageConverters(messageConverters).build(); restTemplate.setRequestFactory(getClientHttpRequestFactory()); return restTemplate; } @Bean public ClientHttpRequestFactory getClientHttpRequestFactory() { // 保持长连接配置，需要在头添加Keep-Alive final ConnectionKeepAliveStrategy myStrategy = new ConnectionKeepAliveStrategy() { @Override public long getKeepAliveDuration(org.apache.http.HttpResponse response, HttpContext context) { // 设置一个链接的最大存活时间 return 5 * 1000L; } }; PoolingHttpClientConnectionManager pollingConnectionManager = new PoolingHttpClientConnectionManager(30, TimeUnit.SECONDS); pollingConnectionManager.setMaxTotal(2000);//最大连接数 pollingConnectionManager.setDefaultMaxPerRoute(200);//同路由的最大连接数 CloseableHttpClient closeableHttpClient = HttpClientBuilder.create().setConnectionManager(pollingConnectionManager).setKeepAliveStrategy(myStrategy).build(); HttpComponentsClientHttpRequestFactory factory = new HttpComponentsClientHttpRequestFactory(closeableHttpClient); factory.setConnectTimeout(3000); factory.setReadTimeout(5000); return factory; }} |
2、使用jdk原生的
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// 添加消息转换器 List messageConverters = new ArrayList(); messageConverters.add(new StringHttpMessageConverter()); messageConverters.add(new MappingJackson2HttpMessageConverter()); //如果useJ2SEHttp申明为true,则使用JDK自带的HttpURLConnection SimpleClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory(); requestFactory.setReadTimeout(3000); requestFactory.setConnectTimeout(3000); restTemplate = new RestTemplate(requestFactory); restTemplate.setMessageConverters(messageConverters); //这里是添加了拦截器 List<ClientHttpRequestInterceptor> interceptorList = new ArrayList<ClientHttpRequestInterceptor>(); interceptorList.add(new RequestInteceptor()); restTemplate.setInterceptors(interceptorList); |
2、拦截器实现ClientHttpRequestInterceptor
（设置头信息的时候回使用到）
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public class RequestInteceptor implements ClientHttpRequestInterceptor { @Override public ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution) throws IOException { request.getHeaders().setAll(AppMetadataUtil.getAPP_METADATA()); String traceId = UUID.randomUUID().toString().replaceAll("-", ""); request.getHeaders().set("TraceId", traceId.toString()); return execution.execute(request, body); }} |
4、常用的方法
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String url = queryInfo?userId={userId}&pageIndex={pageIndex}&pageSize={pageSize}";HashMap<String,Object> parameterMap = new HashMap<String,Object>();parameterMap.put("userId", userId);parameterMap.put("pageIndex", pageIndex);parameterMap.put("pageSize", pageSize); String str = restTemplate.getForObject(url, String.class, parameterMap); String result = restTemp.getForObject(requestUrl.toString(), String.class); //postString url = "http://www.xxx.com/queryInfo"String str = restTemplate.postForObject(url, parameterMap, String.class); //exchange 设置请求头 HttpHeaders headers = new HttpHeaders();headers.setContentType(MediaType.parseMediaType("application/json;charset=UTF-8"));headers.add("Accept", "application/json;charset=UTF-8");HttpEntity<String> httpEntity = new HttpEntity<String>("", headers);RestTemplate restTemplate = RestTemplateUtils.getInstance().getRestTemplate();ResponseEntity<String> exchange = restTemplate.exchange(retailOrderUrl, HttpMethod.GET, httpEntity, String.class);String forObject = exchange.getBody(); MultiValueMap<String, Object> requestEntity = new LinkedMultiValueMap<>(); |
以上为个人经验，希望能给大家一个参考，也希望大家多多支持服务器之家。
原文链接：https://blog.csdn.net/qq9808/article/details/105647182
