@QueryParam如何将没有值的参数转换为布尔值"false"? [英] How can @QueryParam translate a parameter without value to boolean "false"?

问题描述

我想使用类似http://www.example.com/rest/foo?bar的URL，其中bar查询参数没有值，仅它的存在就应该表示变量是true还是false.

I'd like to use an URL like http://www.example.com/rest/foo?bar where the bar query parameter has no value and its presence alone should denote if a variable is true or false.

当前，缺失值假定为""(空)，并传递给new Boolean()，后者将其视为false.

Currently the missing value is assumed to be "" (empty) and passed to new Boolean() which treats it as false.

是否有比定义参数为String自己转换的方法更优雅的定义方式?

Is there a more elegant way of defining it than declaring the parameter to be String and converting it myself?

例如javax.rs.BooleanFlag或类似的课程?

推荐答案

您可以尝试以下操作:

@GET
@Path("/some-path")
public Response myMethod(@Context HttpServletRequest request) {

    boolean isParameterPresent = request.getParameterMap().contains("bar");

    ...
}

但是 peeskillet的答案中显示的解决方案是实现此目的的最聪明的方法.

But the solutions shown in peeskillet's answer are the cleverest ways to achieve it.

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