第7章 分页程序（3课时）

pageBean

package com.neuedu.pojo;

public class PageBean {
    //总条数
    private int count;
    //每页条数
    private int pageSize=1;
    //总页数
    private int totalPage;
    //当前页的页码
    private int currentPage;
    //是否为首页
    private boolean firstPage;
    //是否为尾页
    private boolean lastPage;
    public int getCount() {
        return count;
    }
    public void setCount(int count) {
        this.count = count;
        if(count%pageSize==0){
            totalPage= count/pageSize;
        }else{
            totalPage= count/pageSize+1;
        }
        
    }
    public int getPageSize() {
        return pageSize;
    }
    public void setPageSize(int pageSize) {
        this.pageSize = pageSize;
    }
    
    
    public int getTotalPage() {
        return totalPage;
    }
    public void setTotalPage(int totalPage) {
        this.totalPage = totalPage;
    }
    public int getCurrentPage() {
        return currentPage;
    }
    public void setCurrentPage(int currentPage) {
        this.currentPage = currentPage;
        if(currentPage==1){
            firstPage= true;
        }else{
            firstPage= false;
        }
        if(currentPage==totalPage){
            lastPage= true;
        }else{
            lastPage= false;
        }
    }
    public boolean isFirstPage() {
        return firstPage;
    }
    public void setFirstPage(boolean firstPage) {
        this.firstPage = firstPage;
    }
    public boolean isLastPage() {
        return lastPage;
    }
    public void setLastPage(boolean lastPage) {
        this.lastPage = lastPage;
    }
    
}

改造servlet

  protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    IUserService service=new UserServiceImpl();
    //当前页码
    String curPage=request.getParameter("currentPage");
    if(curPage==null||curPage.isEmpty()){
        curPage="1";
    }
    //查询DB里满足条件的记录总数
    int count=service.count();
    PageBean page=new PageBean();
    page.setCount(count);
    page.setCurrentPage(Integer.parseInt(curPage));
    request.setAttribute("page", page);
    //调用service
    List userList=new ArrayList();
    //返回一个list
    userList=service.findAllUser(page.getCurrentPage(),page.getPageSize());
    //把查询结果放到request里
    request.setAttribute("userList", userList);
    //返回到页面
    request.getRequestDispatcher("/admin/userlist.jsp").forward(request, response);
}

dao 关键方法

汇总总条数

@Override
public int count() {
    int count=0;
    conn=DBUtil.getConnection();
    try {
        ps=conn.prepareStatement("select count(*)   from t_user ");
        rs=ps.executeQuery();
        if(rs.next()){//如果有该用户
            count=rs.getInt(1);
        }
    } catch (SQLException e) {

        e.printStackTrace();
    }
    DBUtil.closeConnection(rs, ps, conn);
    return count;
}

mysql分页

@Override
public List findAllUser(int curPage, int pageSize) {
    conn=DBUtil.getConnection();
    List userList=new ArrayList();
    try {
        ps=conn.prepareStatement("select * from t_user limit ?,?");
        ps.setInt(1, (curPage-1)*pageSize);
        ps.setInt(2, pageSize);
        rs=ps.executeQuery();
        while(rs.next()){
            User user=new User();
            //把从数据库查询到的记录封装到对象里
            user.setId(rs.getInt("user_id"));
            user.setUserName(rs.getString("user_name"));
            user.setUserPwd(rs.getString("user_pwd"));
            user.setEmail(rs.getString("user_email"));
            user.setPower(rs.getInt("user_power"));
            user.setIdCard(rs.getString("user_idcard"));
            //把对象放到list里
            userList.add(user);
        }
    } catch (SQLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    DBUtil.closeConnection(rs, ps, conn);
    return userList;
}

页面

        
        首页  
         
        上一页 
         
        
        下一页 
         
          尾页