查询人员列表

查询人员列表

• Controller

//人员模块表现实现类
@WebServlet(
        name = "PersonnelController",
        urlPatterns = "/personnel.do",
        loadOnStartup = 0
)
public class PersonnelController extends HttpServlet {
    //表现层中获取逻辑层实现类
    private PersonnelService personnelService = PersonnelFactory.getPersonnelService();

    //定义Servlet运行方法, 接收客户端请求, 返回服务器响应
    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.查询人员列表 query
        List<Personnel> list = personnelService.query();
        //2.写入请求作用域
        request.setAttribute("list", list);
        //3.分发器跳转页面
        request.getRequestDispatcher("/view/personnel/list.jsp").forward(request, response);
    }
 }   

• Service

//人员模块逻辑层接口
public interface PersonnelService {
    //查询数据
    List<Personnel> query();
}

//人员模块逻辑层实现类
public class PersonnelServiceImpl implements PersonnelService {
    //逻辑层中获取数据层实现类
    private PersonnelDao personnelDao = PersonnelFactory.getPersonnelDao();

    //查询数据
    @Override
    public List<Personnel> query() {
        return personnelDao.query();
    }
}

• dao

//人员数据层接口
public interface PersonnelDao {
    //查询数据
    List<Personnel> query();
}

//人员模块数据层实现类
public class PersonnelDaoImpl implements PersonnelDao {
    //构造方法
    public PersonnelDaoImpl() {}

    //懒汉模式
    private static PersonnelDaoImpl instance = null;

    public static PersonnelDaoImpl getInstance() {
        //双重校验锁:保证不会出现并发
        if (instance == null) {
            synchronized (PersonnelDaoImpl.class) {
                if (instance == null) {
                    instance = new PersonnelDaoImpl();
                }
            }
        }
        return instance;
    }

    //查询数据
    @Override
    public List<Personnel> query() {
        //查询数据库 MybatisUtils openSession():获取手动提交事务SqlSession,适用于查询方法
        SqlSession session = MybatisUtils.openSession();
        List<Personnel> list = session.selectList("personnel.query");
        session.close();
        return list;
    }
}

• xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="personnel">

    <!--查询数据-->
    <select id="query" resultType="com.javakc.rms.personnel.entity.Personnel">
        select id,name,unit,card,grade,starting_date,state,contract,vehicles_subsidies,
        heating_subsidies,property_subsidies,health_insurance,endowment_insurance,pension_unemployment,
        occupational_pension,injury_fertility,reason from rms_personnel
    </select>

</mapper>