请求接口同时支持表单、json

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java请求接口同时支持json、form-data、表单格式

自定义注解

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@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface MultiFormat {
}

自定义注解解析

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public class MultiFormatMethodProcessor implements HandlerMethodArgumentResolver {

    private ServletModelAttributeMethodProcessor formResolver;
    private RequestResponseBodyMethodProcessor jsonResolver;

    public MultiFormatMethodProcessor() {
        List<HttpMessageConverter<?>> messageConverters = new ArrayList<>();
        PHPMessageConverter PHPMessageConverter = new PHPMessageConverter();
        messageConverters.add(PHPMessageConverter);

        jsonResolver = new JsonMethodArgumentResolver(messageConverters);
        formResolver = new FormMethodArgumentResolver();
    }

    @Override
    public boolean supportsParameter(MethodParameter parameter) {
        MultiFormat ann = parameter.getParameterAnnotation(MultiFormat.class);
        return (ann != null);
    }

    @Override
    public Object resolveArgument(MethodParameter methodParameter, ModelAndViewContainer modelAndViewContainer, NativeWebRequest nativeWebRequest, WebDataBinderFactory webDataBinderFactory) throws Exception {
        ServletRequest servletRequest = nativeWebRequest.getNativeRequest(ServletRequest.class);
        String contentType = servletRequest.getContentType();
        if (contentType == null) {
            throw new IllegalArgumentException("不支持contentType");
        }

        if (contentType.contains("application/json")) {
            return jsonResolver.resolveArgument(methodParameter, modelAndViewContainer, nativeWebRequest, webDataBinderFactory);
        }

        if (contentType.contains("application/x-www-form-urlencoded")) {
            return formResolver.resolveArgument(methodParameter, modelAndViewContainer, nativeWebRequest, webDataBinderFactory);
        }

        if (contentType.contains("multipart")) {
            return formResolver.resolveArgument(methodParameter, modelAndViewContainer, nativeWebRequest, webDataBinderFactory);
        }

        throw new IllegalArgumentException("不支持contentType");
    }
}

添加到Spring Confirguration

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 @Bean
 public MyMvcConfigurer mvcConfigurer() {
 	return new MyMvcConfigurer();
 }

public static class MyMvcConfigurer implements WebMvcConfigurer {
    public void addArgumentResolvers(List<HandlerMethodArgumentResolver> resolvers) {
    	resolvers.add(new GamePHPMethodProcessor());
    }
}

form-data特殊处理

引入jar包
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<dependency>
  <groupId>commons-fileupload</groupId>
  <artifactId>commons-fileupload</artifactId>
  <version>1.3.1</version>
</dependency>
<dependency>
  <groupId>commons-io</groupId>
  <artifactId>commons-io</artifactId>
  <version>2.4</version>
</dependency>
新增解析 bean
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@Bean(name = "multipartResolver")
public MultipartResolver multipartResolver(){
    CommonsMultipartResolver resolver = new CommonsMultipartResolver();
    resolver.setDefaultEncoding("UTF-8");
    resolver.setResolveLazily(true);//resolveLazily属性启用是为了推迟文件解析，以在在UploadAction中捕获文件大小异常
    resolver.setMaxInMemorySize(40960);
    resolver.setMaxUploadSize(50*1024*1024);//上传文件大小 50M 50*1024*1024
    return resolver;
}

只需将@RequestParam 注解改为 @MultiFormat，接口即可同时兼容三种 content-type。

流程为，spring 启动的时候，MyMvcConfigurer 调用 addArgumentResolvers 方法将 MultiFormatMethodProcessor注入，接到请求时，supportsParameter 方法判断是否使用此 resolver，如果为 true，则进入 resolveArgument 方法执行。