用于生成和使用 JSON 的控制器的 Spring RequestMapping [英] Spring RequestMapping for controllers that produce and consume JSON

问题描述

使用多个使用和生成 application/json 的 Spring 控制器，我的代码散落着长注释，例如:

With multiple Spring controllers that consume and produce application/json, my code is littered with long annotations like:

    @RequestMapping(value = "/foo", method = RequestMethod.POST,
            consumes = MediaType.APPLICATION_JSON_VALUE,
            produces = MediaType.APPLICATION_JSON_VALUE)

有没有办法用consumes 和produces 的default 值生成复合/继承/聚合"注释，这样我可以改为写如下:

Is there a way to produce a "composite/inherited/aggregated" annotation with default values for consumes and produces, such that I could instead write something like:

    @JSONRequestMapping(value = "/foo", method = RequestMethod.POST)

我们如何定义上面的 @JSONRequestMapping 之类的东西?注意value 和method 和@RequestMapping 一样传入，也好能传入consumes或 produces 如果默认值不合适.

How do we define something like @JSONRequestMapping above? Notice the value and method passed in just like in @RequestMapping, also good to be able to pass in consumes or produces if the default isn't suitable.

我需要控制返回的内容.我想要 produces/consumes 注释方法，以便获得适当的 Content-Type 标头.

I need to control what I'm returning. I want the produces/consumes annotation-methods so that I get the appropriate Content-Type headers.

推荐答案

从 Spring 4.2.x 开始，您可以创建自定义映射注释，使用 @RequestMapping 作为元注释.所以:

As of Spring 4.2.x, you can create custom mapping annotations, using @RequestMapping as a meta-annotation. So:

有没有办法产生复合/继承/聚合"消费和生产的默认值的注释，这样我可以改为写如下:

Is there a way to produce a "composite/inherited/aggregated" annotation with default values for consumes and produces, such that I could instead write something like:

@JSONRequestMapping(value = "/foo", method = RequestMethod.POST)

是的，有这样的方法.您可以创建如下元注释:

Yes, there is such a way. You can create a meta annotation like following:

@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@RequestMapping(consumes = "application/json", produces = "application/json")
public @interface JsonRequestMapping {
    @AliasFor(annotation = RequestMapping.class, attribute = "value")
    String[] value() default {};

    @AliasFor(annotation = RequestMapping.class, attribute = "method")
    RequestMethod[] method() default {};

    @AliasFor(annotation = RequestMapping.class, attribute = "params")
    String[] params() default {};

    @AliasFor(annotation = RequestMapping.class, attribute = "headers")
    String[] headers() default {};

    @AliasFor(annotation = RequestMapping.class, attribute = "consumes")
    String[] consumes() default {};

    @AliasFor(annotation = RequestMapping.class, attribute = "produces")
    String[] produces() default {};
}

然后您可以使用默认设置，甚至可以根据需要覆盖它们:

Then you can use the default settings or even override them as you want:

@JsonRequestMapping(method = POST)
public String defaultSettings() {
    return "Default settings";
}

@JsonRequestMapping(value = "/override", method = PUT, produces = "text/plain")
public String overrideSome(@RequestBody String json) {
    return json;
}

您可以在 spring 的 javadoc 和 github 维基.

You can read more about AliasFor in spring's javadoc and github wiki.

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