分页查询实战：SQL拼接与封装详解

-----------------------Controller--------------------------------------------
 // 查询
    @RequestMapping("query")
    public String query(HttpServletRequest request,PageUtils pageUtils) {

int dataNum =carservice.pages();
Carbean carbean = pageUtils.getQueryCarbean(request);
Page page=pageUtils.getPage(request,dataNum);
// 传参
List<Carbean> carlist = carservice.query(carbean, page);
// carlist组合查询时用于显示
request.setAttribute("listall", carlist);// 参数注入
return "query.jsp";

    }
---------------------Utils---------------------------------------------------
 // 页面，上一页下一页方法
    public Page getPage(HttpServletRequest request, int dataNum) {
int perNum;
int currentPage = 1;// 默认第一页
request.setAttribute("currentPage", currentPage);// 查询显示第一页
String getPerNum = request.getParameter("perNum");
if (getPerNum == null || getPerNum.equals("")) {
    perNum = 10;

} else {
    perNum = Integer.parseInt(getPerNum);

}
request.setAttribute("perNum", perNum);// 默认每页十条数据