java使用RestTemplate封装post请求方式

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;

									@Configuration

									public 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);

									   //post

									String 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<>();