RestTemplate封装post请求

时间:2022-05-22 小码哥(^_^) 人气:0

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：

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)

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

// 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）

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

 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<>();

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。

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