1.PageBean

package cn.five.util;import lombok.Data;import java.util.List;@Data
public class PageBean<T> {private int totalPages;//总页数private int totalCount;//总条数private int page;//当前页数private int pageSize;//每页长度private List<T> list;//数据集合public PageBean(int totalPages, int totalCount, int page, int pageSize, List<T> list) {this.totalPages = totalPages;this.totalCount = totalCount;this.page = page;this.pageSize = pageSize;this.list = list;}public PageBean() {}
}

2.Dao

    private int getTotalData(String sql, Object... objects) {List<Map> list = select("select count(*) num from (" + sql + ") a", objects);return list == null && list.size() <= 0 ? 0 : Integer.valueOf(list.get(0).get("num").toString());}public PageBean<Map> pageList(int page, int limit, String sql, Object... objects) {int totalData = getTotalData(sql, objects);int totalPage = totalData % limit == 0 ? totalData / limit : (totalData / limit) + 1;if (page < 1) {page = 1;} else if (page > totalPage) {page = totalPage;}sql += "\tlimit\t" + ((page - 1) * limit) + "," + limit;List<Map> list = select(sql, objects);//调用select查询方法return new PageBean<Map>(totalPage, totalData, page, limit, list);}

3.Servlet

private void list(HttpServletRequest request, HttpServletResponse response) {String name = request.getParameter("name") == null ? "%%" : "%" + request.getParameter("name") + "%";Integer page = Integer.valueOf(request.getParameter("page")) == null ? 1 : Integer.valueOf(request.getParameter("page"));Integer limit = Integer.valueOf(request.getParameter("limit") == null ? 10 : Integer.valueOf(request.getParameter("limit")));String sql = "select * from user u RIGHT JOIN role r on u.rid=r.id where uname like ?";//使用idea先写Servlet，直接生成Service接口的list方法，和ServiceImple实现类的重写list方法PageBean<Map> list = new UserServiceImpl().list(page, limit, sql, name);StringToJson.stringToJson(ReturnMessage.success(200, "", list), response);}

4.Service

PageBean<Map> list(Integer page, Integer limit, String sql, String name);

5.ServiceImpl

 @Overridepublic PageBean<Map> list(Integer page, Integer limit, String sql, String name) {return userDao.pageList(page, limit, sql, name);}