@Service
public abstract class BaseService<T> implements IBaseService<T>{public abstract IBaseDao<T> getBaseDao(); public abstract Class<T> getClasss();public Class<T> clsss;{clsss = getClasss();}@Overridepublic Page<T> queryByPage(Page<T> page) {String tableName = clsss.getSimpleName().toLowerCase();List<T> list = new ArrayList<>();//分页 查询 数据   (表名，分页起始位置(利用mysql的limit),每页条数,[条件]) List<HashMap<Object, Object>> listmap =  getBaseDao().queryByPage( tableName, (page.getPage()-1)*page.getSize() , page.getWhere() );// 遍历每个 Map 并通过自定义的方法转换成目标实体类，并添加到结果集list中for (HashMap<Object, Object> hashMap : listmap) {T t1 = hashMapToEntity(hashMap);list.add( t1 );}//将转换好的数据集合放入 Page 对象
        page.setList(list);//根据条件查询数据条数if ( page.getWhere()==null || page.getWhere().length()<=0 ) {page.setCount( queryCount(  ) );}else {page.setCount( queryCount( page.getWhere() ) );}//数据总条数int tmp = page.getCount()/page.getSize();//最大页数page.setMax(page.getCount()<=page.getSize()?1:page.getCount()%page.getSize()>0?tmp+1:tmp);return page;}/*** 将HashMap 转成 实体类对象*/private T hashMapToEntity( Map<Object, Object> map ) {T t = null;try {t = clsss.newInstance();for (Field f : t.getClass().getDeclaredFields()) {f.setAccessible(true);f.set(t,map.get(f.getName()));}} catch (Exception e1) {e1.printStackTrace();}return t;}//无条件查询记录数public int queryCount() {String tableName = clsss.getSimpleName().toLowerCase();return getBaseDao().queryCount( tableName , "1=1" );}//有条件的查找记录数public int queryCount(String where) {String tableName = clsss.getSimpleName().toLowerCase();return getBaseDao().queryCount( tableName , where );}
}

public interface IBaseDao <T> {List<HashMap<Object, Object>> queryByPage(@Param("name")String name, @Param("page")int page, @Param("size")int size,String where);int queryCount( @Param("name")String lowerCase , @Param("where") String where);}

<mapper namespace="base.dao.IBaseDao" ><select id="queryByPage" resultType="hashmap">select * from ${name} where  ${where} limit #{page},#{size} </select><select id="queryCount" resultType="int">select count(1) from ${name} where ${where}</select></mapper>

@Controller
public class Page <T>{private Integer page;   //当前页private Integer size = 5;//每页默认为5private Integer max; //最大页数private Integer count;   //项目条数private String url; //地址private List<Integer> indexs;//要显示的页码private Integer indexNum ;//可现实页码范围内的数量private List<T> list;private String where;//在无参构造中初始化，当然我也在 BaseController 中初始化，//两种方式皆可，反正我都写上了//当然可以写在配置文件中，这是更好的，//方便起见就没有写配置文件了public Page() {page = 1;size = 5;indexNum = 5;where = " 1=1 ";}/*** 计算显示的导航页码*/private void count() {Integer page = getPage();Integer max = getMax();if ( page!=null && max!=null ) {int begin = Math.max(page-indexNum, 1);int end = Math.min(page+indexNum, max);indexs = new ArrayList<>();for( int i = begin ; i <= end ; i++ ) {indexs.add(i);}}}public void setPage(Integer page) {this.page = page;count(); //计算页码
    }public void setMax(Integer max) {this.max = max;count(); //计算页码
    }/*** 省去  普通的get set tostring等*/
}

@Controller
public class BaseController <T> {@InitBinderpublic void initBinder( WebDataBinder binder , final HttpServletRequest request ){binder.registerCustomEditor(Page.class,new PropertyEditorSupport(){@Overridepublic Object getValue() {Page<T> page = (Page<T>) super.getValue();//提前操作  Page 对象if ( page.getPage() == null ) {//没有设页数的时候 默认第一页page.setPage(1);}//设置每页的条数page.setSize(5);//解析request ，获得请求连接String url = request.getRequestURI();String params = request.getQueryString();//获取参数//忽略掉一已经没用的参数，url变成"http://localhost:8080/SSM/stu/queryByPage?1=1"//所以页面中对page传参直接写：&参数=值 接上新的参数即可if ( params!=null && !"".equals(params) ) {url += "?" + params;}else {url += "?1=1";}//找到 每次要访问的地址int index = -1;if ( (index = url.indexOf("&page="))!=-1 ) {url = url.substring(0, index);}page.setUrl(url);return page;}});}
}

<%@ page language="java" contentType="text/html; charset=UTF-8"pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>    <div><c:if test="${page.page==1 }"><a>首页</a><a>上一页</a></c:if><c:if test="${page.page>1 }"><a href="${page.url }&page=1">首页</a><a href="${page.url }&page=${page.page-1}">上一页</a></c:if><!-- 页码 --><c:forEach items="${page.indexs }" var="index">        <c:if test="${index == page.page }"><b>${index}</b></c:if><c:if test="${index != page.page }"><a href="${page.url }&page=${index}"><b>${index}</b></a></c:if></c:forEach><c:if test="${page.page<page.max }"><a href="${page.url }&page=${page.page+1}">下一页</a><a href="${page.url }&page=${page.max}">尾页</a></c:if><c:if test="${page.page==page.max }"><a >下一页</a><a >尾页</a></c:if><a>当前第${page.page }页/共${page.max }页</a>     </div>

@Controller
@RequestMapping("/stu")
public class StuController extends BaseController<Student> {@Autowiredprivate  IStudentService studentService  ;@RequestMapping("/queryByPage")public String queryByPage( Model model , Page<Student> page ) {//这里用 page接收即可，数据也是放在其中的page = studentService.queryByPage( page );model.addAttribute("page",page);//可以选择是否设置条件，可以在一些需要特殊搜索的时候加上条件//可以在页面中传参然后在这里设置条件//比如  年龄大于20的 学生 并分页page.setWhere("age>20");System.out.println(page);return "stulist";
}

public interface IStudentService extends IBaseService<Student> {
}

@Service
public class StudentService extends BaseService<Student> implements IStudentService {@Autowiredprivate IStudentDao mapper;@Overridepublic IBaseDao<Student> getBaseDao() {return mapper;}@Overridepublic Class<Student> getClasss() {return Student.class;}
}

public interface IStudentDao extends IBaseDao<Student> {}