jqgrid接受json数据，分页总页数显示1页
在用jqgrid做一个表格展示时，无论数据多少，页面总显示“共1页”，导致无法翻页，看不到全部数据的问题。
困扰一天半，终于解决，网上没怎么看到类似问题，大多数是显示为0页等等其他问题，所以把自己的解决方案记下来方便可能遇到同样问题的人。
因为整体系统是用springMVC搭的，基于annotation，调用了jackson包自动转换数据位json格式，输出到jqgrid页面。
下面是页面jqgrid部分的代码：
$("#list").jqGrid({
url: "tradeList",
datatype: "json",
mtype: "GET",
colNames: ["transaction Id", "original Transaction Id", "Trade Date",
"transaction Status", "record Status", "Quantity", "transaction Business Code",
"operations" ],
colModel: [
{ name: "transaction Id", index:"transactionId", jsonmap:"transactionId", width: 50 },
{ name: "original Transaction Id", index:"originalTransactionId", jsonmap:"original Transaction Id", width: 70 },
{ name: "Trade Date", index:"tradeDate", jsonmap:"tradeDate", width: 130,
formatter:"date", formatoptions: {srcformat: 'u', newformat: 'm/d/Y H:i:s',}},
{ name: "transaction Status", index:"transactionStatus", jsonmap:"transactionStatus", width: 80 },
{ name: "record Status", index:"recordStatus", jsonmap:"recordStatus", width: 50 },
{ name: "Quantity", index:"quantity", jsonmap:"quantity", width: 80, align: "right" },
{ name: "transaction Business Code", index:"transactionBusinessCode",
jsonmap:"transactionBusinessCode", width: 150},
{ name: "operations", index:"operations", jsonmap:"operations", width: 80 },
],
pager: "#pager",
rowNum: 5,
rowList: [5,10, 20, 30],
sortname: 'transaction Id',
sortorder: 'asc',
viewrecords: true,
caption: "Trade",
});
$("#list").jqGrid('navGrid','#pager');
controller层传数据过去的方法代码如下：
@RequestMapping(value = "/tradeList", method = RequestMethod.GET)
public @ResponseBody List<Trade> getList(){
return tradeService.readTradeList();
}
其中在spring annotation基础上，通过@responseBody和导入的jackson包，将返回的数据列表自动转换为json格式，页面收到的response如下（因太长，未列出完整数据）：
[{"transactionId":"1","version":0,"originalTransactionId":"1","transactionChannel":null,"transactionManagementSystem":null,"transactionCategory":"Trade","transactionBusinessCode":"Trade Create","recordStatus":"ACTIVE","transactionStatus":"New","transactionTime":1401073087000,"transactionUserEntryTime":null,"transactionDatabaseEntryTime":null,"transactionEntryUserId":null,"remark":null,"tradeId":null,"orderId":null,"businessLineId":null,"primaryAccountId":null,"primaryBrokerId":null,"versusAccountId":null,"versusBrokerId":null,"washAccountId":null,"introducerAccountId":null,"tradeDate":1401073087000,"settlementDate":null,"side":null,"productId":null,"exchangeId":null,"tradingCurrencyId":null,"settlementCurrencyId":null,"quantity":100.00,"price":null,"consideration":null,"clearingEntityId":null,"settlementEntityId":null,"lastSettledDate":null,"settledQuantity":null,"settledAmount":null,"salesId":null,"traderId":null,"locationId":null,"tradeStatus":null,"commissionRate":null,"commission":null,"stampDuty":null,"levy":null,"tradingFee":null,"accruedInterest":null,"gst":null,"iftt":null,"trailerFee":null,"figurationList":[]},
{"transactionId":"10"，……]
前台页面接受到了数据，并且按每页5条显示了前5条数据，但是无法翻页查看后面的数据，而pager右边的数据总条数是对的，只有总页数为1，导致无法翻页。
经过各种google以及查看jqgrid的document，终于找到了解决办法。下面说明。
jqgrid接受json数据的格式是这样的：
{
"total": "xxx",
"page": "yyy",
"records": "zzz",
"rows" : [
{"id" :"1", "cell" :["cell11", "cell12", "cell13"]},
{"id" :"2", "cell":["cell21", "cell22", "cell23"]},
... ]}
其中“total”表示总页数，“page”表示当前请求页，“records”为总的记录条数，“rows”对应数据，即上述数据列表，当然“total”“page”等名字可以进行修改，但是需要对应修改jsonReader。
我们的jqgrid页面一直显示总页数为1，即total值未被设置导致，因此只需修改controller层的代码将total等作为response返回给页面即可，修改后的controller代码如下（其中简单地完成了只返回当前请求页面的数据，其实应该放在dao层做比较高效）：
@RequestMapping(value = "/tradeList", method = RequestMethod.GET)
public @ResponseBody Map list(@RequestParam("rows") int pageSize,
@RequestParam("page") int pageNo){
int total;//页面数
Map rows = new HashMap();
//暂时一次读入全部数据
tradeList = tradeService.readTradeList();
//记录总条数
int recordNum = tradeList.size();
//当前页面起止页码数
int beginNo, endNo;
beginNo = pageSize*(pageNo-1);
endNo = beginNo+pageSize-1;
if(endNo>=recordNum){
endNo = recordNum-1;
}
//endNo = beginNo+pageSize-1>=recordNum?recordNum-1:beginNo+pageSize-1;
//当前页面请求的tradelist
List<Trade> tempTradeList = new ArrayList<Trade>();
for(int i=beginNo; i<=endNo; i++){
tempTradeList.add(tradeList.get(i));
}
total = (int) Math.ceil((double)recordNum/pageSize);
rows.put("total", String.valueOf(total));
rows.put("records", String.valueOf(recordNum));
rows.put("rows", tempTradeList);
return rows;
}
这样，页面显示正常，分页功能搞定。