如何使用Ext ComboBox +DWR+SPRING 实现类似GOOGLE的模糊搜索框

我想 使用Ext ComboBox +DWR+SPRING 实现类似GOOGLE的模糊搜索框 ， 代码如下：
Ext.form.SearchHtbhComboBox = Ext.extend(Ext.form.ComboBox,{
        displayField:'htbh',
        typeAhead: false,
        loadingText: 'Searching...',
        pageSize:10,
        hideTrigger:true,
        minChars:0,
        mode:'remote',
        selectOnFocus:true,
        queryParam:'htbh',
        typeAhead: true,
        forceSelection:true,
        tpl: "<tpl for='.'><div class='search-item'>{htbh}</div></tpl>",
        itemSelector: 'div.search-item',
        onSelect: function(record){
    $('drdwmc').value = record.data.drdwbh;
    $('dcdwmc').value = record.data.dcdwbh;
        },
        store: new Ext.data.Store({
        proxy: new Ext.data.DWRProxy(orderMManager.getOrderMsForComboBox),
       reader: new Ext.data.ObjectReader({id:'htbh'},[
        {name: 'htbh', mapping: 'htbh'},
        {name: 'dcdwbh', mapping: 'dcdwbh'},
        {name: 'drdwbh', mapping: 'drdwbh'}
        ])
    })
    });

但是在SPRING 方法中一直无法获取 传过去的参数！错误如下：Missing method or missing parameter converters
ComboBox 传给后台的参数应该如何去取！ 请各位大虾  教教小弟！