自定义MediaType的转换器

由于是Rest风格，使用的是RequestResponseBodyMethodProcessor，我们模仿jackson的convert进行仿写

@PostMapping(value = "/properties",
            consumes = "text/properties;charset=utf-8")
    public Properties properties(@RequestBody Properties properties){
        return properties;
    }

public class PropertiesConvert extends AbstractGenericHttpMessageConverter<Properties> {

    /**
     * 支持的处理类型
     */
    public PropertiesConvert() {
        super(new MediaType("text","properties"));
    }

    /**
     * 返回值处理
     */
    @Override
    protected void writeInternal(Properties properties, Type type, HttpOutputMessage outputMessage) throws IOException, HttpMessageNotWritableException {
        HttpHeaders httpHeaders = outputMessage.getHeaders();
        Charset charset = httpHeaders.getContentType().getCharset();
        charset = charset == null ? Charset.forName("utf-8") : charset;

        OutputStream outputStream = outputMessage.getBody();
        Writer writer = new OutputStreamWriter(outputStream,charset);
        properties.store(writer,"my convert");
    }

    /**
     * 入参转换
     */
    @Override
    protected Properties readInternal(Class<? extends Properties> clazz, HttpInputMessage inputMessage) throws IOException, HttpMessageNotReadableException {
        HttpHeaders httpHeaders = inputMessage.getHeaders();
        Charset charset = httpHeaders.getContentType().getCharset();
        charset = charset == null ? Charset.forName("utf-8") : charset;

        InputStream inputStream = inputMessage.getBody();
        InputStreamReader reader = new InputStreamReader(inputStream,charset);
        Properties properties = new Properties();
        properties.load(reader);

        return properties;
    }

    @Override
    public Properties read(Type type, Class<?> contextClass, HttpInputMessage inputMessage) throws IOException, HttpMessageNotReadableException {
        return readInternal(null,inputMessage);
    }
}

@Configuration
public class MvcConfig extends WebMvcConfigurerAdapter {
    @Override
    public void extendMessageConverters(List<HttpMessageConverter<?>> converters) {
        //由于json可以处理properties，如果不指定位置添加是添加到末尾，在选择convert处理时会优先选择json的而不是我们自定义的
        converters.add(0,new PropertiesConvert());
    }
}