springboot 使用fastjson替代默认jackson（踩坑路）

最安全做法使用bean替代默认转换器方法

@Configuration
public class MyConfiguration {
    
    /**
     * 配置消息转换器
     * new HttpMessageConverters(true, converters); 
     * 一定要设为true才能替换否则不会替换
     * @return 返回一个消息转换的bean
     */
  	@Bean
	public HttpMessageConverters fastJsonMessageConverters() {
		List<HttpMessageConverter<?>> converters = new ArrayList<>();
		//需要定义一个convert转换消息的对象;
		FastJsonHttpMessageConverter fastConverter = new FastJsonHttpMessageConverter();
		//添加fastJson的配置信息;
		FastJsonConfig fastJsonConfig = new FastJsonConfig();
		fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat);
		//全局时间配置
		fastJsonConfig.setDateFormat("yyyy-MM-dd HH:mm:ss");
		fastJsonConfig.setCharset(Charset.forName("UTF-8"));
		//处理中文乱码问题
		List<MediaType> fastMediaTypes = new ArrayList<>();
		fastMediaTypes.add(MediaType.APPLICATION_JSON_UTF8);
		//在convert中添加配置信息.
		fastConverter.setSupportedMediaTypes(fastMediaTypes);
		fastConverter.setFastJsonConfig(fastJsonConfig);
		converters.add(0,fastConverter);
		return new HttpMessageConverters(converters);
	}

第二种做法

实现WebMvcConfigurer,需要将顺序改为0，或者比jackson前面就可以了

@Configuration
public class SpringMvcConfigure implements WebMvcConfiguration{

    /**
     * 配置消息转换器
     * @param converters
     */
    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
       //需要定义一个convert转换消息的对象;
        FastJsonHttpMessageConverter fastConverter = new FastJsonHttpMessageConverter();
        //添加fastJson的配置信息;
        FastJsonConfig fastJsonConfig = new FastJsonConfig();
        fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat);
        //全局时间配置
        fastJsonConfig.setDateFormat("yyyy-MM-dd HH:mm:ss");
        fastJsonConfig.setCharset(Charset.forName("UTF-8"));
        //处理中文乱码问题
        List<MediaType> fastMediaTypes = new ArrayList<>();
        fastMediaTypes.add(MediaType.APPLICATION_JSON_UTF8);
        //在convert中添加配置信息.
        fastConverter.setSupportedMediaTypes(fastMediaTypes);
        fastConverter.setFastJsonConfig(fastJsonConfig);
        converters.add(0,fastConverter);
    }
}

第三种实现父类,缺点很明显，完全接管的springmvc，默认配置全部失效，需要重新自己配置

@Configuration
public class SpringMvcConfigure extends WebMvcConfigurationSupport{

    /**
     * 配置消息转换器
     * @param converters
     */
    @Override
   protected void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        //需要定义一个convert转换消息的对象;
        FastJsonHttpMessageConverter fastConverter = new FastJsonHttpMessageConverter();
        //添加fastJson的配置信息;
        FastJsonConfig fastJsonConfig = new FastJsonConfig();
        fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat);
        //全局时间配置
        fastJsonConfig.setDateFormat("yyyy-MM-dd HH:mm:ss");
        fastJsonConfig.setCharset(Charset.forName("UTF-8"));
        //处理中文乱码问题
        List<MediaType> fastMediaTypes = new ArrayList<>();
        fastMediaTypes.add(MediaType.APPLICATION_JSON_UTF8);
        //在convert中添加配置信息.
        fastConverter.setSupportedMediaTypes(fastMediaTypes);
        fastConverter.setFastJsonConfig(fastJsonConfig);
        converters.add(fastConverter);
        super.configureMessageConverters(converters);
    }
    /*
     * 
     *重写静态路径
     * @parm registry 配置源
     */
     @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/**")
                .addResourceLocations("classpath:/static/");
    }
}

注意：没重新的会失效，默认配置会被这个完全代替。

参考附录

https://docshome.gitbooks.io/springboot/content/pages/spring-boot-features.html#boot-features-spring-mvc-auto-configuration

https://blog.youkuaiyun.com/bluuusea/article/details/79665440

https://segmentfault.com/a/1190000015975405

https://github.com/spring-projects/spring-boot/issues/12389

https://www.cnblogs.com/soul-wonder/p/9052422.html

https://docs.spring.io/spring-boot/docs/2.1.6.RELEASE/reference/htmlsingle/#howto-customize-the-responsebody-rendering