springboot 利用configureMessageConverters add FastJsonHttpMessageConverter 实现返回JSON值 null to ""

/** * 文件名：@WebConfiguration.java <br/> * @author tomas <br/>

import com.alibaba.fastjson.support.config.FastJsonConfig;import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.boot.actuate.health.ApplicationHealthIndicator;import org.springframework.boot.actuate.health.HealthIndicator;import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;import org.springframework.context.EnvironmentAware;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.core.env.Environment;import org.springframework.http.MediaType;import org.springframework.http.converter.HttpMessageConverter;import org.springframework.web.servlet.config.annotation.EnableWebMvc;import org.springframework.web.servlet.config.annotation.InterceptorRegistry;import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

import java.util.ArrayList;import java.util.List;

import static com.alibaba.fastjson.serializer.SerializerFeature.*;

/** * 类名：WebConfiguration  <br /> * * 功能：Web相关配置 * * @author tomas <br /> * 创建时间：2016年7月27日 下午3:57:19  <br /> * @version 2016年7月27日*/@Configuration@EnableWebMvcpublic class FrontConfiguration extends WebMvcConfigurerAdapter implements EnvironmentAware {   // 日志记录器 private static final Logger logger = LoggerFactory.getLogger(FrontConfiguration.class);

 // 当前的环境对象 protected Environment environment;

   @Override public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {      super.configureMessageConverters(converters); //1.需要先定义一个 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(); // 不忽略对象属性中的null值 fastJsonConfig.setSerializerFeatures(            PrettyFormat, WriteNullListAsEmpty, WriteNullStringAsEmpty); //3、在convert中添加配置信息. fastConverter.setFastJsonConfig(fastJsonConfig); //4、将convert添加到converters当中. converters.add(fastConverter); }

   public void addResourceHandlers(ResourceHandlerRegistry registry) {      registry.addResourceHandler("swagger-ui.html")            .addResourceLocations("classpath:/META-INF/resources/"); registry.addResourceHandler("favicon.ico")            .addResourceLocations("classpath:/static/favicon.ico"); registry.addResourceHandler("/webjars/**")            .addResourceLocations("classpath:/META-INF/resources/webjars/"); }   /**    * Set the {@code Environment} that this object runs in.    *    * @param environment */ @Override public void setEnvironment(Environment environment) {      this.environment = environment; }}
@Overridepublic void configureMessageConverters(List<HttpMessageConverter<?>> converters) {   super.configureMessageConverters(converters); //1.需要先定义一个 convert 转换消息的对象; FastJsonHttpMessageConverter fastConverter = new FastJsonHttpMessageConverter(); List<MediaType> supportedMediaTypes = new ArrayList<>(); supportedMediaTypes.add(MediaType.APPLICATION_JSON); supportedMediaTypes.add(MediaType.APPLICATION_JSON_UTF8); supportedMediaTypes.add(MediaType.APPLICATION_ATOM_XML); supportedMediaTypes.add(MediaType.APPLICATION_FORM_URLENCODED); supportedMediaTypes.add(MediaType.APPLICATION_OCTET_STREAM); supportedMediaTypes.add(MediaType.APPLICATION_PDF); supportedMediaTypes.add(MediaType.APPLICATION_RSS_XML); supportedMediaTypes.add(MediaType.APPLICATION_XHTML_XML); supportedMediaTypes.add(MediaType.APPLICATION_XML); supportedMediaTypes.add(MediaType.IMAGE_GIF); supportedMediaTypes.add(MediaType.IMAGE_JPEG); supportedMediaTypes.add(MediaType.IMAGE_PNG); supportedMediaTypes.add(MediaType.TEXT_EVENT_STREAM); supportedMediaTypes.add(MediaType.TEXT_HTML); supportedMediaTypes.add(MediaType.TEXT_MARKDOWN); supportedMediaTypes.add(MediaType.TEXT_PLAIN); supportedMediaTypes.add(MediaType.TEXT_XML); fastConverter.setSupportedMediaTypes(supportedMediaTypes); //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(); // 不忽略对象属性中的null值 fastJsonConfig.setSerializerFeatures(         PrettyFormat, WriteNullListAsEmpty, WriteNullStringAsEmpty); //3、在convert中添加配置信息. fastConverter.setFastJsonConfig(fastJsonConfig); //4、将convert添加到converters当中. converters.add(fastConverter);}