Grails 2.5.6如何解析请求并将JSON映射到POGO? [英] How does Grails 2.5.6 parse and map request JSON to POGO?

问题描述

Tl; dr :我想在MyCmdTest."data bind works" rel ="nofollow noreferrer">此代码为绿色.
感谢Jeff Scott Brown 把我带到那儿.

Tl;dr: I want to get test MyCmdTest."data bind works" in this code green.
Thanks to Jeff Scott Brown for getting me that far.

我有一个POGO，其中包含一些来自JSON的自定义转换，我希望可以在Grails控制器中收到它们:

I have a POGO with some custom conversions from JSON which I expect to receive in a Grails controller:

def myAction(MyCmd myData) {
    ...
}

使用:

@Validateable
class MyCmd {
    SomeType some

    void setSome(Object value) {
        this.some = customMap(value)
    }
}

请注意customMap如何从JSON值(例如，字符串)创建SomeType的实例.假设默认设置器不起作用；例如，一个不止一次的模式就是这样的枚举:

Note how customMap creates an instance of SomeType from a JSON value (say, a String). Let's assume the default setter won't work; for instance, an pattern we have around more than once is an enum like this:

enum SomeType {
    Foo(17, "foos"),
    Bar(19, "barista")

    int id
    String jsonName

    SomeType(id, jsonName) {
        this.id = id
        this.jsonName = jsonName
    }
}

在这里，customMap将采用整数或字符串，并返回匹配的大小写(如果不适合，则返回null).

Here, customMap would take an integer or string, and return the matching case (or null, if none fits).

现在，我具有以下形式的单元测试:

Now, I have a unit test of the following form:

class RegistrationCmdTest extends Specification {
    String validData // hard-coded, conforms to JSON schema

    void test() {
        MyCmd cmd = new MyCmd(JSON.parse(validData))
        // check members: success

        MyCmd cmd2 = JSON.parse(validData) as MyCmd
        // check members: success
    }
}

显然，在两个变体中都调用setSome.

Apparently, setSome is called in both variants.

我还有一个控制器单元测试，该测试将请求JSON设置为相同的字符串:

I also have a controller unit test that sets the request JSON to the same string:

void "register successfully"() {
    given:
    ResonseCmd = someMock()

    when:
    controller.request.method = 'POST'
    controller.request.contentType = "application/json"
    controller.request.json = validData
    controller.myAction()

    then:
    noExceptionThrown()
    // successful validations: service called, etc.
}

基本上，同一件事也可以作为集成测试.

Basically the same thing also runs as integration test.

但是，运行完整应用程序时，映射失败； some == null.

However, the mapping fails when running the full application; some == null.

我必须实现或重写哪些方法，以便Grails调用我的转换(此处为customMap)，而不是在不知道要做什么的地方插入null?

Which methods do I have to implement or override so Grails calls my conversions (here, customMap) instead of inserting null where it doesn't know what to do?

推荐答案

可以使用@BindUsing批注来自定义数据绑定:

It's possible to customize data binding using the @BindUsing annotation:

@BindUsing({ newCmd, jsonMap ->
    customMap(jsonMap['someType'])
})
SomeType someType

另请参见 MWE存储库

来源: Hubert Klein Ikkink @ DZone ，

Sources: Hubert Klein Ikkink @ DZone, Official Docs (there are other ways to customize)

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