使用SpringMVC注解@RequestParam(value="XXX",required=false)时需要注意的问题

错误描述：

[java] view
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@RequestMapping(value = "/index")

public String index(@RequestParam(value = "action", required = false)

String action, @RequestParam(value = "notIncludeTypeId", required = false)

int notIncludeTypeId){

// .... 省略代码

}

当可选参数“notIncludeTypeId”为空时，系统出现如下错误：

[plain] view
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Optional int parameter 'notIncludeTypeId' is not present

but cannot be translated into a null value due to being declared as a primitive type.

Consider declaring it as object wrapper for the corresponding primitive type.

错误原因：

当可选参数“notIncludeTypeId”不存在时，Spring默认将其赋值为null，但由于notIncludeTypeId已定于为基本类型int，所以赋值失败！

解决方法：

“Consider declaring it as object wrapper for the corresponding primitive type.”建议使用包装类型代替基本类型，如使用“Integer”代替“int”