方案一：啟動類繼承WebMvcConfigurerAdapter,覆蓋方法configureMessageConverters

...
@SpringBootApplication
public class UserApplication extends WebMvcConfigurerAdapter{
 
  @Override
  public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
    super.configureMessageConverters(converters);
 
    
 
// 初始化轉換器
    FastJsonHttpMessageConverter fastConvert = new FastJsonHttpMessageConverter();
    // 初始化一個轉換器配置
    FastJsonConfig fastJsonConfig = new FastJsonConfig();
 //用於美化格式，可註釋掉   fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat);
    // 將配置設置給轉換器並添加到HttpMessageConverter轉換器列表中
    fastConvert.setFastJsonConfig(fastJsonConfig);
 
    converters.add(fastConvert);
  }
 
  
 
public static void main(String[] args) {
    SpringApplication.run(UserApplication.class, args);
  }
}

方案二：在啟動類中註入 HttpMessageConverters

...
@SpringBootApplication
public class UserApplication {
    /**
     * 配置FastJson為Spring Boot默認JSON解析框架
     * @return  HttpMessageConverters
     */
    @Bean
    
 
public HttpMessageConverters fastJsonHttpMessageConverters() {
        // 1.定義一個converters轉換消息的對象
        FastJsonHttpMessageConverter fastConverter = new FastJsonHttpMessageConverter();
        // 2.添加fastjson的配置信息，比如: 是否需要格式化返回的json數據
        FastJsonConfig fastJsonConfig = new FastJsonConfig();
        fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat);
        // 3.在converter中添加配置信息
        fastConverter.setFastJsonConfig(fastJsonConfig);
        // 4.將converter賦值給HttpMessageConverter
        HttpMessageConverter<?> converter = fastConverter;
        // 5.返回HttpMessageConverters對象
        return new HttpMessageConverters(converter);
    }
    public static void main(String[] args) {
        SpringApplication.run(UserApplication.class, args);
    }
}

mark一下

Spring Boot默認的JSON解析框架設置