<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

<!-- web場景自動(dòng)引入了json場景 -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-json</artifactId>
    <version>2.3.4.RELEASE</version>
    <scope>compile</scope>
</dependency>

@Controller
public class ResponseTestController {
    @ResponseBody //原理就是利用返回值處理器里面消息轉(zhuǎn)換器進(jìn)行處理
    @GetMapping("/test/person")
    public Person getPerson(){
        Person person = new Person();
        person.setAge(28);
        person.setBirth(new Date());
        person.setUserName("zhangsan");
        return person;
    }

}

<dependency>
    <groupId>com.fasterxml.jackson.dataformat</groupId>
    <artifactId>jackson-dataformat-xml</artifactId>
</dependency>

spring:
    contentnegotiation:
      favor-parameter: true  #開啟請(qǐng)求參數(shù)內(nèi)容協(xié)商模式

WebMvcConfigurationSupport
jackson2XmlPresent = ClassUtils.isPresent("com.fasterxml.jackson.dataformat.xml.XmlMapper", classLoader);

if (jackson2XmlPresent) {
                    Jackson2ObjectMapperBuilder builder = Jackson2ObjectMapperBuilder.xml();
                    if (this.applicationContext != null) {
                            builder.applicationContext(this.applicationContext);
                    }
                    messageConverters.add(new MappingJackson2XmlHttpMessageConverter(builder.build()));
            }

@Configuration
public class WebConfig implements WebMvcConfigurer {

    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        FastJsonHttpMessageConverter fastConverter = new FastJsonHttpMessageConverter();
        List<MediaType> fastMediaTypes = new ArrayList<>();
        fastMediaTypes.add(MediaType.TEXT_HTML);
        fastMediaTypes.add(MediaType.APPLICATION_JSON);
        fastConverter.setSupportedMediaTypes(fastMediaTypes);
        FastJsonConfig fastJsonConfig = new FastJsonConfig();
        fastJsonConfig.setSerializerFeatures(
            SerializerFeature.WriteMapNullValue,
            SerializerFeature.WriteNullStringAsEmpty,
            SerializerFeature.WriteNullListAsEmpty,
            SerializerFeature.WriteDateUseDateFormat);
        SerializeConfig serializeConfig = SerializeConfig.globalInstance;
        serializeConfig.put(BigInteger.class, ToStringSerializer.instance);
        serializeConfig.put(Long.class, ToStringSerializer.instance);
        serializeConfig.put(Long.TYPE, ToStringSerializer.instance);
        fastJsonConfig.setSerializeConfig(serializeConfig);
        fastConverter.setFastJsonConfig(fastJsonConfig);
        converters.add(fastConverter);
    }
}

@Data
public class Person {
    private String userName;
    private Integer age;
    //使用fastjson的注解進(jìn)行轉(zhuǎn)換
    @JSONField(format = "yyyy-MM-dd")
    private Date birth;
    private Pet pet;
}

@Bean
public WebMvcConfigurer webMvcConfigurer(){
    return new WebMvcConfigurer() {

        @Override
        public void extendMessageConverters(List<HttpMessageConverter<?>> converters) {

        }
    }
}

@Configuration(proxyBeanMethods = false)
public class WebConfig {
    @Bean
    public WebMvcConfigurer webMvcConfigurer(){
        return new WebMvcConfigurer() {

            @Override
            public void extendMessageConverters(List<HttpMessageConverter<?>> converters) {
                converters.add(new GuiguMessageConverter());
            }
        }
    }
}

/**
 * 自定義的Converter
 */
public class GuiguMessageConverter implements HttpMessageConverter<Person> {

    @Override
    public boolean canRead(Class<?> clazz, MediaType mediaType) {
        return false;
    }

    @Override
    public boolean canWrite(Class<?> clazz, MediaType mediaType) {
        return clazz.isAssignableFrom(Person.class);
    }

    /**
     * 服務(wù)器要統(tǒng)計(jì)所有MessageConverter都能寫出哪些內(nèi)容類型
     *
     * application/x-guigu
     * @return
     */
    @Override
    public List<MediaType> getSupportedMediaTypes() {
        return MediaType.parseMediaTypes("application/x-guigu");
    }

    @Override
    public Person read(Class<? extends Person> clazz, HttpInputMessage inputMessage) throws IOException, HttpMessageNotReadableException {
        return null;
    }

    @Override
    public void write(Person person, MediaType contentType, HttpOutputMessage outputMessage) throws IOException, HttpMessageNotWritableException {
        //自定義協(xié)議數(shù)據(jù)的寫出
        String data = person.getUserName()+";"+person.getAge()+";"+person.getBirth();


        //寫出去
        OutputStream body = outputMessage.getBody();
        body.write(data.getBytes());
    }
}

import java.util.Date;

@Controller
public class ResponseTestController {

    /**
     * 1、瀏覽器發(fā)請(qǐng)求直接返回 xml    [application/xml]        jacksonXmlConverter
     * 2、如果是ajax請(qǐng)求 返回 json   [application/json]      jacksonJsonConverter
     * 3、如果硅谷app發(fā)請(qǐng)求，返回自定義協(xié)議數(shù)據(jù)  [appliaction/x-guigu]   xxxxConverter
     *          屬性值1;屬性值2;
     *
     * 步驟：
     * 1、添加自定義的MessageConverter進(jìn)系統(tǒng)底層
     * 2、系統(tǒng)底層就會(huì)統(tǒng)計(jì)出所有MessageConverter能操作哪些類型
     * 3、客戶端內(nèi)容協(xié)商 [guigu--->guigu]
     *
     * 作業(yè)：如何以參數(shù)的方式進(jìn)行內(nèi)容協(xié)商
     * @return
     */
    @ResponseBody  //利用返回值處理器里面的消息轉(zhuǎn)換器進(jìn)行處理
    @GetMapping(value = "/test/person")
    public Person getPerson(){
        Person person = new Person();
        person.setAge(28);
        person.setBirth(new Date());
        person.setUserName("zhangsan");
        return person;
    }
}