[JavaScript知识库]求问后端数据如何传给echarts饼图里的data里

已经困扰我一个多星期了，求大佬指导，救救孩子吧
前端代码：

series: [
						{
							name: 'Nightingale Chart',
							type: 'pie',
							radius: [50, 200],
							center: ['50%', '50%'],
							roseType: 'area',
							left: '30%',
							right: '30',
							itemStyle: {
								borderRadius: 6
							},
							data:
							[
							{ value: 40, name: '医疗' },
							{ value: 38, name: '交通' },
							{ value: 32, name: '就餐' },
							{ value: 30, name: '学习' },
							{ value: 28, name: '娱乐' },
							{ value: 26, name: '其他' }

						]

DAO层：

```handlebars
public class ExpenditureRateDao extends BaseDao {
    public ExpenditureRateDao(String tableName) {
        super(tableName);
    }

    public List<Map<String,Object>> getExpenditureByUserName(Map<String,String> map){
        List<Map<String,Object>> list = null;
        List<Map<String,Object>> expenditureTypeList = null;
        String sql = "select * from expenditure,expendituretype where userName=? and expenditure.expenditureType=expendituretype.expenditureTypeId";
        list=super.executeQuery(sql,map.get("userName"));

        ExpenditureTypeDao expenditureTypeDao = new ExpenditureTypeDao("expendituretype");

        expenditureTypeList = expenditureTypeDao.getAll();

        for (Map<String,Object> map2 :expenditureTypeList){
            map2.put("sum",0);
        }
        
        // map1是支出数据
        // map2是支出类型

        for (Map<String,Object> map1 :list){
            for (Map<String,Object> map2 :expenditureTypeList){
                // 如果取出的支出数据的类型与支出类型一样
                if (Integer.parseInt(map1.get("expenditureTypeId").toString()) == Integer.parseInt(map2.get("expenditureTypeId").toString())){
                    map2.put("sum",Double.parseDouble(map2.get("sum").toString())+Double.parseDouble(map1.get("expenditure").toString()));
                    break;
                }
            }
        }

        return expenditureTypeList;
    }

}

server：

public class ExpenditureRateServer {
    public List<Map<String,Object>> getExpenditureByUserName(Map<String,String> map){
        List<Map<String,Object>> list = null;
        ExpenditureRateDao expenditureRateDao = new ExpenditureRateDao("expenditure");
        list = expenditureRateDao.getExpenditureByUserName(map);
        return list;
    }
}

servlet

@WebServlet( "/ExpenditureRateServlet")
public class ExpenditureRateServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doGet(request,response);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        Map<String,String[]> maps = request.getParameterMap();
        Map<String,String> map = Util.exchange(maps);

        ExpenditureRateServer expenditureRateServer = new ExpenditureRateServer();
        List<Map<String,Object>> list = expenditureRateServer.getExpenditureByUserName(map);

        String date = JSON.toJSONString(list);
        PrintWriter printWriter = response.getWriter();
        printWriter.print(date);
        printWriter.close();
    }
}