JAVA跨域、RestTemplate高併發下異常與配置、JSON數據Long轉String

## 跨域支持 import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.web.cors.CorsConfiguration; import org.springframework.web.cors.UrlBasedCorsConfigurationSource; import org.springframework.web.filter.CorsFilter; @Configuration public class CorsConfig { /** * 跨域支持 * * @return */ @Bean public CorsFilter corsFilter() { final UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource(); final CorsConfiguration config = new CorsConfiguration(); config.setAllowCredentials(true); // 容許cookies跨域 config.addAllowedOrigin("*");// #容許向該服務器提交請求的URI，*表示所有容許 config.addAllowedHeader("*");// #容許訪問的頭信息,*表示所有 config.setMaxAge(18000L);// 預檢請求的緩存時間（秒），即在這個時間段裏，對於相同的跨域請求不會再預檢了 config.addAllowedMethod("*");// 容許提交請求的方法，*表示所有容許 source.registerCorsConfiguration("/**", config); return new CorsFilter(source); } } ## RestTemplate高併發下異常與配置 import org.apache.http.client.HttpClient; import org.apache.http.impl.client.HttpClientBuilder; import org.apache.http.impl.client.HttpClients; import org.apache.http.impl.conn.PoolingHttpClientConnectionManager; import org.springframework.cloud.client.loadbalancer.LoadBalanced; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.http.client.HttpComponentsClientHttpRequestFactory; import org.springframework.web.client.DefaultResponseErrorHandler; import org.springframework.web.client.RestTemplate; /** * * RestTemplate高併發下異常與配置說明 * 一、java.util.ConcurrentModificationException * 二、java.net.SocketTimeoutException Connection timed out */ @Configuration public class RestTemplateConfig { @Bean @LoadBalanced public RestTemplate restTemplate() { // 長鏈接 PoolingHttpClientConnectionManager pollingConnectionManager = new PoolingHttpClientConnectionManager(); // 總鏈接數 pollingConnectionManager.setMaxTotal(1000); // 同路由的併發數 pollingConnectionManager.setDefaultMaxPerRoute(1000); HttpClientBuilder httpClientBuilder = HttpClients.custom(); httpClientBuilder.setConnectionManager(pollingConnectionManager); // 重試次數，默認是3次，沒有開啓 // httpClientBuilder.setRetryHandler(new DefaultHttpRequestRetryHandler(3, true)); HttpClient httpClient = httpClientBuilder.build(); HttpComponentsClientHttpRequestFactory clientHttpRequestFactory = new HttpComponentsClientHttpRequestFactory( httpClient); // 鏈接超時 ms clientHttpRequestFactory.setConnectTimeout(12000); // 數據讀取超時時間，即SocketTimeout ms clientHttpRequestFactory.setReadTimeout(12000); // 鏈接不夠用的等待時間，不宜過長，必須設置，好比鏈接不夠用時，時間過長將是災難性的 clientHttpRequestFactory.setConnectionRequestTimeout(200); // 緩衝請求數據，默認值是true。經過POST或者PUT大量發送數據時，建議將此屬性更改成false，以避免耗盡內存。 // clientHttpRequestFactory.setBufferRequestBody(false); RestTemplate restTemplate = new RestTemplate(); restTemplate.setRequestFactory(clientHttpRequestFactory); restTemplate.setErrorHandler(new DefaultResponseErrorHandler()); return restTemplate; } } ## json數據Long爲String /** * * @description: 返回json是轉換long爲string * @create: 2019-08-02 17:49 **/ import com.fasterxml.jackson.databind.ObjectMapper; import com.fasterxml.jackson.databind.module.SimpleModule; import com.fasterxml.jackson.databind.ser.std.ToStringSerializer; import org.springframework.context.annotation.Configuration; import org.springframework.http.converter.HttpMessageConverter; import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter; import org.springframework.web.servlet.config.annotation.EnableWebMvc; import org.springframework.web.servlet.config.annotation.WebMvcConfigurer; import java.util.List; @EnableWebMvc @Configuration public class WebDataConvertConfig implements WebMvcConfigurer { @Override public void configureMessageConverters(List > converters) { MappingJackson2HttpMessageConverter jackson2HttpMessageConverter = new MappingJackson2HttpMessageConverter(); ObjectMapper objectMapper = new ObjectMapper(); /** * 序列換成json時,將全部的long變成string * 由於js中得數字類型不能包含全部的java long值 */ SimpleModule simpleModule = new SimpleModule(); simpleModule.addSerializer(Long.class, ToStringSerializer.instance); simpleModule.addSerializer(Long.TYPE, ToStringSerializer.instance); objectMapper.registerModule(simpleModule); jackson2HttpMessageConverter.setObjectMapper(objectMapper); converters.add(jackson2HttpMessageConverter); } } > 本文由做者pm1280415703:JAVA實驗手冊 發佈,交流羣：583284584！