提交数据url太长导致提交失败

使用了dojo开发。在datagrid过滤的时候。为了让过滤好处理，直接设置为完全二叉树的方式来存查询条件。但是在提交数据的时候，默认是get?url的方式。结果导致条件选择一两个,url会特别长。然后会报404错误。差点把前面的设计推掉，重来。项目就差一小部分了。时间上也来不及了。硬着头皮，看了一天的js源代码，我只能说，俺对js的世界无法理解啊。反复的试验了好久，硬是将rest的get请求，改为了post请求。代码如下：

require(["dojo/_base/declare", "dojox/rpc/JsonRest", "dojox/data/JsonRestStore", "dojo/dom", "dojo/domReady!"],
        function (declare, rpcJsonRest,JsonRestStore, locale, dom) {
            return declare("mydata.JsonRestStore", [dojox.data.JsonRestStore], {//我的rest并不标准{Data:data,ErrorNo:1,ErrorInfo:errorinfo}这种形式。
                _processResults: function (results, deferred) {
                    // index the results
                    if (results.ErrorNo > 0) {
                        alert(results.ErrorInfo);
                        throw new Error(results.ErrorInfo || '');
                    }
                    var count = results.Data.TotalRowCount;
                    results = results.Data.Items;
                    // if we don't know the length, and it is partial result, we will guess that it is twice as big, that will work for most widgets
                    return { totalCount: deferred.fullLength || (deferred.request.count == count ? (deferred.request.start || 0) + count * 2 : count), items: results };
                },
                _doQuery: function (args) {//重写了一个_doQuery
                    var query = typeof args.queryStr == 'string' ? args.queryStr : args.query;
                    //var myservice = this.service({}, args);
                    var myservice = this.service._getRequest({ operation: query.operation }, args)//从这里开始新的调用。
                    var xhrArgs = {
                        url: myservice.url,
                        handleAs: "json",
                        headers: {
                            Accept: "application/json,application/javascript",
                            Range: myservice.headers.Range
                        },
                        content: { filtercodtion: query.filtercodtion }
                    };
                    var deferred = dojo.xhrPost(xhrArgs); //rpcJsonRest.query(this.service, query, args);原来的调用。
                    var self = this;
                    if (this.loadReferencedSchema) {
                        deferred.addCallback(function (result) {
                            var contentType = deferred.ioArgs && deferred.ioArgs.xhr && deferred.ioArgs.xhr.getResponseHeader("Content-Type");
                            var schemaRef = contentType && contentType.match(/definedbys*=s*([^;]*)/);
                            if (contentType && !schemaRef) {
                                schemaRef = deferred.ioArgs.xhr.getResponseHeader("Link");
                                schemaRef = schemaRef && schemaRef.match(/<([^>]*)>;s*rel="?definedby"?/);
                            }
                            schemaRef = schemaRef && schemaRef[1];
                            if (schemaRef) {
                                var serviceAndId = rpcJsonRest.getServiceAndId((self.target + schemaRef).replace(/^(.*/)?(w+://)|[^/.]+/../|^.*/(/)/, "$2$3"));
                                var schemaDeferred = rpcJsonRest.byId(serviceAndId.service, serviceAndId.id);
                                schemaDeferred.addCallbacks(function (newSchema) {
                                    lang.mixin(self.schema, newSchema);
                                    return result;
                                }, function (error) {
                                    alert(error);
                                    console.error(error); // log it, but don't let it cause the main request to fail
                                    return result;
                                });
                                return schemaDeferred;
                            }
                            return undefined;//don't change anything, and deal with the stupid post-commit lint complaints
                        });
                    }
                    return deferred;
                }
            });
        }
);

解决问题的思路因为觉得太复杂[的确是复杂]，而不知道怎么入手。要改变方法。耗的时间太久了。