JAVA跨域、RestTemplate高并发下异常与配置、JSON数据Long转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); // 允许cookies跨域 config.addAllowedOrigin("*");// #允许向该服务器提交请求的URI，*表示全部允许 config.addAllowedHeader("*");// #允许访问的头信息,*表示全部 config.setMaxAge(18000L);// 预检请求的缓存时间（秒），即在这个时间段里，对于相同的跨域请求不会再预检了 config.addAllowedMethod("*");// 允许提交请求的方法，*表示全部允许 source.registerCorsConfiguration("/**", config); return new CorsFilter(source); } } ## RestTemplate高并发下异常与配置 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高并发下异常与配置说明 * 1、java.util.ConcurrentModificationException * 2、java.net.SocketTimeoutException Connection timed out */ @Configuration public class RestTemplateConfig { @Bean @LoadBalanced public RestTemplate restTemplate() { // 长连接 PoolingHttpClientConnectionManager pollingConnectionManager = new PoolingHttpClientConnectionManager(); // 总连接数 pollingConnectionManager.setMaxTotal(1000); // 同路由的并发数 pollingConnectionManager.setDefaultMaxPerRoute(1000); HttpClientBuilder httpClientBuilder = HttpClients.custom(); httpClientBuilder.setConnectionManager(pollingConnectionManager); // 重试次数，默认是3次，没有开启 // httpClientBuilder.setRetryHandler(new DefaultHttpRequestRetryHandler(3, true)); HttpClient httpClient = httpClientBuilder.build(); HttpComponentsClientHttpRequestFactory clientHttpRequestFactory = new HttpComponentsClientHttpRequestFactory( httpClient); // 连接超时 ms clientHttpRequestFactory.setConnectTimeout(12000); // 数据读取超时时间，即SocketTimeout ms clientHttpRequestFactory.setReadTimeout(12000); // 连接不够用的等待时间，不宜过长，必须设置，比如连接不够用时，时间过长将是灾难性的 clientHttpRequestFactory.setConnectionRequestTimeout(200); // 缓冲请求数据，默认值是true。通过POST或者PUT大量发送数据时，建议将此属性更改为false，以免耗尽内存。 // clientHttpRequestFactory.setBufferRequestBody(false); RestTemplate restTemplate = new RestTemplate(); restTemplate.setRequestFactory(clientHttpRequestFactory); restTemplate.setErrorHandler(new DefaultResponseErrorHandler()); return restTemplate; } } ## json数据Long为String /** * * @description: 返回json是转换long为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(); /** * 序列换成json时,将所有的long变成string * 因为js中得数字类型不能包含所有的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); } } > 本文由作者pm1280415703:JAVA实验手册 发布,交流群：583284584！