SSM框架实战详细教程（十四）贯穿项目实战之三层架构

        之前我们的项目足够简单，所以使用的是两层架构，现在为了学习Spring，需要使用行业中常见的三层架构，关于分层开发的原则请看下图：

        本次对项目的调整，主要是由之前的controller调用dao，改成controller调用service，service调用dao。项目结构：

        涉及修改的代码：
StudentController.java:

package controller;

import dao.BanJiDao;
import dao.MybatisSqlSession;
import dao.StudentDao;
import entity.BanJi;
import entity.Student;
import org.apache.ibatis.session.SqlSession;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;
import service.BanJiService;
import service.StudentService;
import service.impl.BanJiServiceImpl;
import service.impl.StudentServiceImpl;

import java.util.List;

@Controller
public class StudentController {
    @RequestMapping("show")
    public ModelAndView search() {
        StudentService stuService =new StudentServiceImpl();
        List<Student> list = stuService.searchAll();
        ModelAndView mv = new ModelAndView("show");
        mv.addObject("stus", list);

        return mv;
    }

    @RequestMapping("showAdd")
    public ModelAndView showAdd() {
        BanJiService bjService=new BanJiServiceImpl();
        List<BanJi> bjList=bjService.searchAll();
        ModelAndView mv = new ModelAndView("showAdd");
        mv.addObject("bjs",bjList);
        return mv;
    }

    @RequestMapping("add")
    public String add(Student stu) {
        StudentService stuService =new StudentServiceImpl();

        boolean flag = stuService.add(stu);
        if (flag) {
            return "redirect:show.do";
        }


        return null;
    }

    @RequestMapping("showUpdate")
    public ModelAndView showUpdate(int id) {
        StudentService stuService =new StudentServiceImpl();
        Student stu = stuService.search(id);
        ModelAndView mv = new ModelAndView("showUpdate");
        mv.addObject("stu", stu);
        return mv;
    }
    @RequestMapping("update")
    public String update(Student stu) {
        StudentService stuService =new StudentServiceImpl();

        boolean flag = stuService.update(stu);
        if (flag) {
            return "redirect:show.do";
        }
        return null;
    }
    @RequestMapping("delete")
    public String delete(int id) {
        StudentService stuService =new StudentServiceImpl();

        boolean flag = stuService.delete(id);
        if (flag) {
            return "redirect:show.do";
        }
        return null;
    }
}

StudentService.java:

package service;

import entity.Student;

import java.util.List;

public interface StudentService {
    List<Student> searchAll();

    Student search(int id);

    boolean add(Student stu);

    boolean update(Student stu);

    boolean delete(int id);

}

StudentServiceImpl.java:

package service.impl;

import dao.MybatisSqlSession;
import dao.StudentDao;
import entity.Student;
import org.apache.ibatis.session.SqlSession;
import service.StudentService;

import java.util.List;

public class StudentServiceImpl implements StudentService {
    @Override
    public List<Student> searchAll() {
        SqlSession sqlSession = MybatisSqlSession.getSqlSession();
        StudentDao stuDao = sqlSession.getMapper(StudentDao.class);
        List<Student> list=stuDao.searchAll();
        sqlSession.commit();
        sqlSession.close();
        return list;
    }

    @Override
    public Student search(int id) {
        SqlSession sqlSession = MybatisSqlSession.getSqlSession();
        StudentDao stuDao = sqlSession.getMapper(StudentDao.class);
        Student stu = stuDao.search(id);
        sqlSession.commit();
        sqlSession.close();
        return stu;
    }

    @Override
    public boolean add(Student stu) {
        SqlSession sqlSession = MybatisSqlSession.getSqlSession();
        StudentDao stuDao = sqlSession.getMapper(StudentDao.class);
        int rs = stuDao.add(stu);
        sqlSession.commit();
        sqlSession.close();
        return rs>0;
    }

    @Override
    public boolean update(Student stu) {
        SqlSession sqlSession = MybatisSqlSession.getSqlSession();
        StudentDao stuDao = sqlSession.getMapper(StudentDao.class);
        int rs = stuDao.update(stu);
        sqlSession.commit();
        sqlSession.close();
        return rs>0;
    }

    @Override
    public boolean delete(int id) {
        SqlSession sqlSession = MybatisSqlSession.getSqlSession();
        StudentDao stuDao = sqlSession.getMapper(StudentDao.class);
        int rs = stuDao.delete(id);
        sqlSession.commit();
        sqlSession.close();
        return rs>0;    }
}