基于spring+mybatis框架的管理系统：简单实现增、删、改、查。(三)

一、

分页

1.pageInfo 5
currentpage size list totalpage totalpage

2.dao
1.查询所要展现的数据 2.查询总条数

3.service
给pageinfo 赋值

4.controller
把pageinfo 传递给页面

5.在页面展现

pagehelper
1.导jar包
2.applicationcontext里面告诉数据库我们用了pagehelper这个插件
3.service 在执行具体sql前
PageHelper.startPage(pageNum,size);

4.controller
PageInfo pageInfo=new PageInfo<>();
pageInfo.setList(userService.findAll(pageNum,size));

二、

基于“基于spring+mybatis框架的管理系统：简单实现增、删、改、查。(二)”基础进行修改与添加

模糊查询：
1.UserMapper.xml

 <select id="findAll" resultType="com.zhongruan.bean.User" parameterType="String">
        select * from tb_user
        <where>
            <if test="searchname!=null">
                username like "%"#{searchname}"%"
            </if>
        </where>
    </select>

2.IUserDao ：

 List<User> findAll(@Param("searchname") String searchname);

3.IUserService：

 List<User> findAll(int currentPage,int size,String searchname);

4.UserService：

@Override
    public List<User> findAll(int currentPage,int size,String searchname) {
        PageHelper.startPage(currentPage,size);
        return userDao.findAll(searchname);
    }

5.在zhongruan包新建一个filter包，新建LoginFilter.java

package com.zhongruan.filter;


import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;

public class LoginFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request= (HttpServletRequest) servletRequest;
        HttpServletResponse response= (HttpServletResponse) servletResponse;
        HttpSession session=request.getSession();
        if (session.getAttribute("username")==null&&request.getRequestURI().indexOf("/login.do")==-1){
            response.sendRedirect("index.jsp");
        }else {
            filterChain.doFilter(request,response);
        }
    }

    @Override
    public void destroy() {

    }
}

6.UserController

 @RequestMapping("/findAll.do")
    public ModelAndView findAll(@RequestParam(defaultValue = "1") int pageNum,
                                @RequestParam(defaultValue = "5") int size,
                                String searchname, HttpSession session){
        ModelAndView modelAndView=new ModelAndView();
        String username= (String) session.getAttribute("username");
        if (username==null){
          modelAndView.setViewName("failure.jsp");
            return modelAndView;
        }
        if (searchname!=null){
            session.setAttribute("searchname",searchname);
        }else {
            searchname= (String) session.getAttribute("searchname");
        }
       List<User> users=userService.findAll(pageNum,size, searchname);
        PageInfo<User> pageInfo=new PageInfo<>(users);
        modelAndView.setViewName("allUser.jsp");
        modelAndView.addObject("pageInfo",pageInfo);
        return modelAndView;
    }