ajax – 将Map传递给springMVC控制器

这是我如何做的细节：

Ajax调用如下

var tags = {};
tags["foo"] = "bar";
tags["whee"] = "whizzz";


$.post("doTestMap.do",{"tags" : tags },function(data,textStatus,jqXHR) {
if (textStatus == 'success') {
    //handle success
    console.log("doTest returned " + data);
} else {
    console.err("doTest returned " + data);
}
});

然后在控制器方面我有：

@RequestMapping(value="/publisher/doTestMap.do",method=RequestMethod.POST)
public @ResponseBody String doTestMap(@RequestParam(value = "tags",defaultValue = "") HashMap<String,String> tags,HttpServletRequest request) {  //

    System.out.println(tags);

    return "cool";
}

不幸的是我系统地得到了

org.springframework.beans.ConversionNotSupportedException: Failed to convert value of type 'java.lang.String' to required type 'java.util.Map'; nested exception is java.lang.IllegalStateException: Cannot convert value of type [java.lang.String] to required type [java.util.Map]: no matching editors or conversion strategy found

我究竟做错了什么 ？

谢谢.