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

错误描述：

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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  
}  

@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： 

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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.  

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”

博客原地址：http://blog.csdn.net/hellostory/article/details/7519358