spring boot杂记fastjson swagger

感觉有用，先记录下来。

一.Spring Boot中使用Fastjson代替Jackson

1.1 为什么使用Fastjson代替Jackson

Jackson最主要的原因是Jackson在处理对象之前的循环嵌套关系时不便。什么是对象间的循环嵌套？ 比如A有一个List，B对象里又有一个A对象，当然返回A对象的Json字符串时，如果是Jackson就会发生异常，因为Jackson天生不具备处理这种关系的能力，而Fastjson正好具备了这种能力。

1.2 使用Fastjson代替Jackson过程

1.引入依赖

<dependency> <groupId> com.alibaba </groupId> <artifactId> fastjson </artifactId> <version> 1.2.29 </version> </dependency>

三种实现方式

import java.util.ArrayList; import java.util.List; import org.springframework.context.annotation.Configuration; import org.springframework.http.MediaType; import org.springframework.http.converter.HttpMessageConverter; import org.springframework.web.servlet.HandlerExceptionResolver; import org.springframework.web.servlet.config.annotation.EnableWebMvc; import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter; import com.alibaba.fastjson.serializer.SerializerFeature; import com.alibaba.fastjson.support.config.FastJsonConfig; import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter; /**  * Spring MVC全局一场解析器  *   * @author xujin  *  */ @Configuration @EnableWebMvc public class ApplicationExceptionAdapter extends WebMvcConfigurerAdapter { /** * 配置fastJson 用于替代jackson */ @Override public void configureMessageConverters( List<HttpMessageConverter<?>> converters) { super.configureMessageConverters(converters); // 1.定义一个convert 转换消息的对象 FastJsonHttpMessageConverter fastConverter = new FastJsonHttpMessageConverter(); // 2 添加fastjson 的配置信息 比如 是否要格式化 返回的json数据 FastJsonConfig fastJsonConfig = new FastJsonConfig(); fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat); fastConverter.setFastJsonConfig(fastJsonConfig); // 解决乱码的问题 List<MediaType> fastMediaTypes = new ArrayList<>(); fastMediaTypes.add(MediaType.APPLICATION_JSON_UTF8); fastConverter.setSupportedMediaTypes(fastMediaTypes); converters.add(fastConverter); } /** 用自己的全局异常解析器替换Spring MVC本身的异常解析器 **/ @Override public void configureHandlerExceptionResolvers( List<HandlerExceptionResolver> exceptionResolvers) { exceptionResolvers.add(new ApplicationExceptionResolver()); super.configureHandlerExceptionResolvers(exceptionResolvers); } } 或者

@EnableWebMvc public class JanusAdminApplication extends WebMvcConfigurerAdapter { /** * 配置fastJson 用于替代jackson */ @Override public void configureMessageConverters( List<HttpMessageConverter<?>> converters) { super.configureMessageConverters(converters); // 1.定义一个convert 转换消息的对象 FastJsonHttpMessageConverter fastConverter = new FastJsonHttpMessageConverter(); // 2 添加fastjson 的配置信息 比如 是否要格式化 返回的json数据 FastJsonConfig fastJsonConfig = new FastJsonConfig(); fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat); fastConverter.setFastJsonConfig(fastJsonConfig); // 解决乱码的问题 List<MediaType> fastMediaTypes = new ArrayList<>(); fastMediaTypes.add(MediaType.APPLICATION_JSON_UTF8); fastConverter.setSupportedMediaTypes(fastMediaTypes); converters.add(fastConverter); } public static void main(String[] args) { SpringApplication.run(JanusAdminApplication.class, args); } }

二.Spring Boot自定义Spring MVC异常解析器

public class ApplicationExceptionResolver implements HandlerExceptionResolver { /** * Log类 */ private Logger logger = Logger.getLogger(getClass()); @Override public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) { logger.info("异常拦截器执行开始。"); // 输出 异常信息 String msgContent = ResourcesUtil.getValue(Config.MESSAGE, ex.getMessage()); logger.error("发生异常:" + msgContent, ex); // 将异常信息转json输出 this.writeJsonByFilter(response, this.resolveExceptionCustom(ex), null, null); logger.info("异常拦截器执行结束。"); return new ModelAndView(); } /** * 异常信息解析方法 * * @param ex */ private ResultData resolveExceptionCustom(Exception ex) { ResultData model = new ResultData(); if (ex instanceof ApplicationException) { // 抛出的是系统自定义异常 model.setMsgCode(this.getMsgCode(ex)); } else if (ex instanceof UnauthenticatedException) { // 没有权限的异常 model.setMsgCode("ECOMMON00002"); } else { // 未知错误 model.setMsgCode("ECOMMON00001"); } return model; } private String getMsgCode(Exception ex) { // 输出 异常信息 String msgCode = ex.getMessage(); // 若返回的异常不直接是自定义异常，而是经过封装的异常 if (msgCode.charAt(0) != 'E' && msgCode.charAt(0) != 'W' && msgCode.charAt(0) != 'I') { msgCode = ex.getCause().getMessage(); } return msgCode; } /** * 将对象转换成JSON字符串，并响应回前台 */ protected void writeJsonByFilter(HttpServletResponse response, Object object, String[] includesProperties, String[] excludesProperties) { try { // excludes优先于includes FastjsonFilterUtil filter = new FastjsonFilterUtil(); if (excludesProperties != null && excludesProperties.length > 0) { filter.getExcludes().addAll( Arrays.<String> asList(excludesProperties)); } if (includesProperties != null && includesProperties.length > 0) { filter.getIncludes().addAll( Arrays.<String> asList(includesProperties)); } // 使用SerializerFeature.WriteDateUseDateFormat特性来序列化日期格式的类型为yyyy-MM-dd // hh24:mi:ss // 使用SerializerFeature.DisableCircularReferenceDetect特性关闭引用检测和生成 String json = JSON.toJSONString(object, filter, SerializerFeature.WriteDateUseDateFormat, SerializerFeature.DisableCircularReferenceDetect); logger.info("JSON String is:" + json); response.setContentType("text/html;charset=utf-8"); response.getWriter().write(json); response.getWriter().flush(); response.getWriter().close(); } catch (IOException e) { logger.error("An error occurred when object was converted to JSON", e); } } }

三 Spring Boot集成swagger

3.1 Spring Boot集成swagger

<dependency>

   <groupId>io.springfox</groupId>

   <artifactId>springfox-swagger2</artifactId>

   <version>2.5.0</version>

</dependency>

<dependency>

   <groupId>io.springfox</groupId>

   <artifactId>springfox-swagger-ui</artifactId>

   <version>2.5.0</version>

</dependency>

import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.context.annotation.Profile; import springfox.documentation.builders.ApiInfoBuilder; import springfox.documentation.builders.PathSelectors; import springfox.documentation.builders.RequestHandlerSelectors; import springfox.documentation.service.ApiInfo; import springfox.documentation.spi.DocumentationType; import springfox.documentation.spring.web.plugins.Docket; import springfox.documentation.swagger2.annotations.EnableSwagger2; /** * Swagger2 配置 * * @author xujin * */ @Configuration @EnableSwagger2 // 在生产环境不开启 @Profile({ "dev", "local" }) public class Swagger2Config { @Bean public Docket createRestApi() { return new Docket(DocumentationType.SWAGGER_2) .apiInfo(apiInfo()) .select() .apis(RequestHandlerSelectors .basePackage("org.xujin.janus.admin.controller")) .paths(PathSelectors.any()).build(); } private ApiInfo apiInfo() { return new ApiInfoBuilder().title("Janus网关管控平台") .description("Janus网关管控平台").contact("Software_King@qq.com") .version("1.0").build(); } }

3.2 遇到的问题

访问http://localhost:8080/swagger-ui.html，控制台出现错误

1.页面显示默认报错页面。后台报错：

No handler found for GET /swagger-ui.html

2.显示Swagger空白页面

原因分析: 在访问http://localhost:8080/swagger-ui.html 时，这个swagger-ui.html相关的所有前端静态文件都在springfox-swagger-ui-2.6.1.jar里面。Spring Boot自动配置本身不会自动把/swagger-ui.html这个路径映射到对应的目录META-INF/resources/下面。我们加上这个映射即可。

@Configuration @EnableWebMvc public class ApplicationExceptionAdapter extends WebMvcConfigurerAdapter { @Override public void addResourceHandlers(ResourceHandlerRegistry registry) { registry.addResourceHandler("swagger-ui.html").addResourceLocations( "classpath:/META-INF/resources/"); registry.addResourceHandler("/webjars/**").addResourceLocations( "classpath:/META-INF/resources/webjars/"); } }

原文地址：http://mp.weixin.qq.com/s/3A7KJEvzIYfJL795HifK7w