1.RestTemplate添加RequestHeader如content-type可通過httpclient設置

List<Header> headers = new ArrayList<>();headers.add(new BasicHeader("User-Agent", "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.16 Safari/537.36"));headers.add(new BasicHeader("Accept-Encoding", "gzip,deflate"));headers.add(new BasicHeader("Accept-Language", "zh-CN"));headers.add(new BasicHeader("Connection", "Keep-Alive"));httpClientBuilder.setDefaultHeaders(headers);HttpClient httpClient = httpClientBuilder.build();// httpClient連接配置，底層是配置RequestConfigHttpComponentsClientHttpRequestFactory clientHttpRequestFactory = new HttpComponentsClientHttpRequestFactory(httpClient);

restTemplate.setRequestFactory(clientHttpRequestFactory);

2.使用中進行異常處理

try catch

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public String postRemoteData(ParameterRo ro) throws UnsupportedEncodingException {/*** 設置請求頭*/HttpHeaders headers = new HttpHeaders();headers.setContentType(MediaType.parseMediaType("application/json;charset=UTF-8"));headers.add("Accept", MediaType.APPLICATION_JSON.toString());/*** POST請求參數，根據需要進行封裝*/String bodyData = new String(Base64Util.encodeData(JSON.toJSONString(ro)).getBytes("UTF-8"), "UTF-8");/*** 查看HttpEntity的構造方法，包含只有請求頭和只有請求體的情況*/HttpEntity<String> httpEntity = new HttpEntity<String>(bodyData, headers);/*** 執行操作*/String result = restTemplate.postForObject(remoteUrl, httpEntity, String.class);return result;}

3.控制超時，使用連接池，編碼轉換

RestTemplate是Spring提供的用于訪問Rest服務的客戶端，RestTemplate提供了多種便捷訪問遠程Http服務的方法，能夠大大提高客戶端的編寫效率。
調用RestTemplate的默認構造函數，RestTemplate對象在底層通過使用java.net包下的實現創建HTTP 請求，可以通過使用ClientHttpRequestFactory指定不同的HTTP請求方式。
ClientHttpRequestFactory接口主要提供了兩種實現方式

• 一種是SimpleClientHttpRequestFactory，使用J2SE提供的方式（既java.net包提供的方式）創建底層的Http請求連接。
• 一種方式是使用HttpComponentsClientHttpRequestFactory方式，底層使用HttpClient訪問遠程的Http服務，使用HttpClient可以配置連接池和證書等信息。

?　　RestTemplate默認是使用SimpleClientHttpRequestFactory，內部是調用jdk的HttpConnection，默認超時為-1

public RestTemplate(ClientHttpRequestFactory requestFactory) {this();setRequestFactory(requestFactory);}

? ? ?其中，第二個構造方法中可以傳入ClientHttpRequestFactory參數，第一個進行默認初始化，因為我們經常需要對請求超時進行設置并能 夠對超時進行后續處理，而第 ? ? ?一個構造方法，我們無法控制超時時間，第二個構造中的ClientHttpRequestFactory接口的實現類中存在 timeout屬性，因此選用第二個構造方法

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//創建HTTP客戶端工廠 private ClientHttpRequestFactory createFactory() { if (this.maxTotalConnect <= 0) { SimpleClientHttpRequestFactory factory = new SimpleClientHttpRequestFactory(); factory.setConnectTimeout(this.connectTimeout); factory.setReadTimeout(this.readTimeout); return factory; } HttpClient httpClient = HttpClientBuilder.create().setMaxConnTotal(this.maxTotalConnect) .setMaxConnPerRoute(this.maxConnectPerRoute).build(); HttpComponentsClientHttpRequestFactory factory = new HttpComponentsClientHttpRequestFactory( httpClient); factory.setConnectTimeout(this.connectTimeout); factory.setReadTimeout(this.readTimeout); return factory; } //初始化RestTemplate,并加入spring的Bean工廠，由spring統一管理 @Bean @ConditionalOnMissingBean(RestTemplate.class) public RestTemplate getRestTemplate() { RestTemplate restTemplate = new RestTemplate(this.createFactory()); List<HttpMessageConverter<?>> converterList = restTemplate.getMessageConverters(); //重新設置StringHttpMessageConverter字符集為UTF-8，解決中文亂碼問題 HttpMessageConverter<?> converterTarget = null; for (HttpMessageConverter<?> item : converterList) { if (StringHttpMessageConverter.class == item.getClass()) { converterTarget = item; break; } } if (null != converterTarget) { converterList.remove(converterTarget); } converterList.add(1, new StringHttpMessageConverter(StandardCharsets.UTF_8)); //加入FastJson轉換器 converterList.add(new FastJsonHttpMessageConverter4()); return restTemplate; }

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@Bean public HttpMessageConverters fastjsonConverter() { FastJsonConfig fastJsonConfig = new FastJsonConfig(); //自定義格式化輸出 fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat, SerializerFeature.WriteNullStringAsEmpty, SerializerFeature.WriteNullNumberAsZero); FastJsonHttpMessageConverter4 fastjson = new FastJsonHttpMessageConverter4(); fastjson.setFastJsonConfig(fastJsonConfig); return new HttpMessageConverters(fastjson); }

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@Component @Lazy(false) public class RestClient {private static final Logger LOGGER = LoggerFactory.getLogger(SimpleRestClient.class);private static RestTemplate restTemplate;static {// 長連接保持30秒PoolingHttpClientConnectionManager pollingConnectionManager = new PoolingHttpClientConnectionManager(30, TimeUnit.SECONDS);// 總連接數pollingConnectionManager.setMaxTotal(1000);// 同路由的并發數pollingConnectionManager.setDefaultMaxPerRoute(1000);HttpClientBuilder httpClientBuilder = HttpClients.custom();httpClientBuilder.setConnectionManager(pollingConnectionManager);// 重試次數，默認是3次，沒有開啟httpClientBuilder.setRetryHandler(new DefaultHttpRequestRetryHandler(2, true));// 保持長連接配置，需要在頭添加Keep-AlivehttpClientBuilder.setKeepAliveStrategy(new DefaultConnectionKeepAliveStrategy());// RequestConfig.Builder builder = RequestConfig.custom(); // builder.setConnectionRequestTimeout(200); // builder.setConnectTimeout(5000); // builder.setSocketTimeout(5000); // // RequestConfig requestConfig = builder.build(); // httpClientBuilder.setDefaultRequestConfig(requestConfig);List<Header> headers = new ArrayList<>();headers.add(new BasicHeader("User-Agent", "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.16 Safari/537.36"));headers.add(new BasicHeader("Accept-Encoding", "gzip,deflate"));headers.add(new BasicHeader("Accept-Language", "zh-CN"));headers.add(new BasicHeader("Connection", "Keep-Alive"));httpClientBuilder.setDefaultHeaders(headers);HttpClient httpClient = httpClientBuilder.build();// httpClient連接配置，底層是配置RequestConfigHttpComponentsClientHttpRequestFactory clientHttpRequestFactory = new HttpComponentsClientHttpRequestFactory(httpClient);// 連接超時clientHttpRequestFactory.setConnectTimeout(5000);// 數據讀取超時時間，即SocketTimeoutclientHttpRequestFactory.setReadTimeout(5000);// 連接不夠用的等待時間，不宜過長，必須設置，比如連接不夠用時，時間過長將是災難性的clientHttpRequestFactory.setConnectionRequestTimeout(200);// 緩沖請求數據，默認值是true。通過POST或者PUT大量發送數據時，建議將此屬性更改為false，以免耗盡內存。// clientHttpRequestFactory.setBufferRequestBody(false);// 添加內容轉換器List<HttpMessageConverter<?>> messageConverters = new ArrayList<>();messageConverters.add(new StringHttpMessageConverter(Charset.forName("UTF-8")));messageConverters.add(new FormHttpMessageConverter());messageConverters.add(new MappingJackson2XmlHttpMessageConverter());messageConverters.add(new MappingJackson2HttpMessageConverter());restTemplate = new RestTemplate(messageConverters);restTemplate.setRequestFactory(clientHttpRequestFactory);restTemplate.setErrorHandler(new DefaultResponseErrorHandler());LOGGER.info("RestClient初始化完成");}private RestClient() {}@PostConstructpublic static RestTemplate getClient() {return restTemplate;}}
參考網頁：http://blog.csdn.net/clj198606061111/article/details/70227571，http://blog.csdn.net/u010476464/article/details/50067079，http://www.cnblogs.com/winner-0715/p/6258139.html

轉載于:https://www.cnblogs.com/guoyinglin/p/7732422.html

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