Maven的Web项目中pojo层、Dao层、service层、servlet层、filter层实现一次登录操作

目录

1、pojo层：实体类层

2、Dao层，写数据库操作的包。

        （1）首先配置数据库文件，创建db.properties文件

        （2）编写基础公共类BaseDao （通用）

        （3）首先编写dao层登录用户登录的接口

        （4）编写dao接口的实现类

3、service层，调用Dao层进行业务实现（用户登录操作）

        （1）编写业务层接口

        （2）编写业务层业务层实现类

4、servlet层操作（接收用户页面参数，调用service层，转发视图）

5、filter层（过滤器层）

        （1）编写字符编码过滤器

        （2）编写页面权限过滤器

6、别忘了servlet和filter要在web.xml里面注册

1、pojo层：实体类层

        主要就是编写实体类，私有属性，无参构造，set和get方法，tostring

package com.zhou.pojo; import java.util.Date; public class User {     private Integer id; // id     private String userCode; // 用户编码     private String userName; // 用户姓名     private String userPassword; // 用户密码     private Integer gender; // 性别     private Date birthday; // 出生日期     private String phone; // 电话     private String address; // 地址     private Integer userRole; // 用户角色     private Integer createdBy; // 创建者     private Date creationDate; // 创建时间     private Integer modifyBy; // 更新者     private Date modifyDate; // 更新时间     private Long age; // 年龄     private String userRoleName; // 用户角色名称     public String getUserRoleName(){         return userRoleName;     }     public void setUserRoleName(String userRoleName){         this.userRoleName = userRoleName;     }     public long getAge(){         Date date = new Date();         long age = date.getYear() - birthday.getTime();         return age;     }     public Integer getId() {         return id;     }     public void setId(Integer id) {         this.id = id;     }     public String getUserCode() {         return userCode;     }     public void setUserCode(String userCode) {         this.userCode = userCode;     }     public String getUserName() {         return userName;     }     public void setUserName(String userName) {         this.userName = userName;     }     public String getUserPassword() {         return userPassword;     }     public void setUserPassword(String userPassword) {         this.userPassword = userPassword;     }     public Integer getGender() {         return gender;     }     public void setGender(Integer gender) {         this.gender = gender;     }     public Date getBirthday() {         return birthday;     }     public void setBirthday(Date birthday) {         this.birthday = birthday;     }     public String getPhone() {         return phone;     }     public void setPhone(String phone) {         this.phone = phone;     }     public String getAddress() {         return address;     }     public void setAddress(String address) {         this.address = address;     }     public Integer getUserRole() {         return userRole;     }     public void setUserRole(Integer userRole) {         this.userRole = userRole;     }     public Integer getCreatedBy() {         return createdBy;     }     public void setCreatedBy(Integer createdBy) {         this.createdBy = createdBy;     }     public Date getCreationDate() {         return creationDate;     }     public void setCreationDate(Date creationDate) {         this.creationDate = creationDate;     }     public Integer getModifyBy() {         return modifyBy;     }     public void setModifyBy(Integer modifyBy) {         this.modifyBy = modifyBy;     }     public Date getModifyDate() {         return modifyDate;     }     public void setModifyDate(Date modifyDate) {         this.modifyDate = modifyDate;     } }

2、Dao层，写数据库操作的包。

        目录结构：

                

        （1）首先配置数据库文件，创建db.properties文件

        （2）编写基础公共类BaseDao （通用）

                （封装好，以后可以一直用，包括，连接数据库，查询数据库，增删改数据库，关闭连接）

package com.zhou.dao; import java.io.IOException; import java.io.InputStream; import java.sql.*; import java.util.Properties; // 操作数据库的公共库 public class BaseDao {     private static String driver;     private static String url;     private static String username;     private static String password;     // 静态代码块，类加载的时候就启动了     static {         Properties properties = new Properties();         // 通过类加载器获得对应的资源         InputStream is = BaseDao.class.getClassLoader().getResourceAsStream("db.properties");         try {             properties.load(is);         } catch (IOException e) {             throw new RuntimeException(e);         }         driver = properties.getProperty("driver");         url = properties.getProperty("url");         username = properties.getProperty("username");         password = properties.getProperty("password");     }     // 获取数据库的连接     public static Connection getConnection(){         Connection connection = null;         try {             Class.forName(driver);             connection = DriverManager.getConnection(url, username, password);         } catch (Exception e) {             throw new RuntimeException(e);         }         return connection;     }     // 编写查询公共类     public static ResultSet execute(Connection connection, String sql, Object[] params, ResultSet resultSet, PreparedStatement preparedStatement) throws SQLException {         // 预编译的sql，在后面直接执行就可以了         preparedStatement = connection.prepareStatement(sql);         for (int i = 0; i < params.length; i++) {             // setObject 占位符从1开始，但是我们的数组是从0开始             preparedStatement.setObject(i+1, params[i]);         }         resultSet = preparedStatement.executeQuery();         return resultSet;     }     // 编写增删改公共方法     public static int execute(Connection connection, String sql, Object[] params, PreparedStatement preparedStatement) throws SQLException {         preparedStatement = connection.prepareStatement(sql);         for (int i = 0; i < params.length; i++) {             // setObject 占位符从1开始，但是我们的数组是从0开始             preparedStatement.setObject(i+1, params[i]);         }         int updateRows = preparedStatement.executeUpdate();         return updateRows;     }     // 释放资源     public static boolean closeResource(Connection connection, PreparedStatement preparedStatement, ResultSet resultSet){         boolean flag = true;         if (resultSet != null){             try {                 resultSet.close();                 // GC回收                 resultSet = null;             } catch (SQLException e) {                 e.printStackTrace();                 flag = false;             }         }         if (preparedStatement != null){             try {                 preparedStatement.close();                 // GC回收                 preparedStatement = null;             } catch (SQLException e) {                 e.printStackTrace();                 flag = false;             }         }         if (connection != null){             try {                 connection.close();                 // GC回收                 connection = null;             } catch (SQLException e) {                 e.printStackTrace();                 flag = false;             }         }         return flag;     } }

        （3）首先编写dao层登录用户登录的接口

package com.zhou.dao.user; import com.zhou.pojo.User; import java.sql.Connection; import java.sql.SQLException; public interface UserDao {     // 得到要登录的用户     public User getLoginUser(Connection connection, String userCode) throws SQLException; }

        （4）编写dao接口的实现类

package com.zhou.dao.user; import com.zhou.dao.BaseDao; import com.zhou.pojo.User; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; public class UserDaoImpl implements UserDao{     // 得到要登录的用户     public User getLoginUser(Connection connection, String userCode) throws SQLException {         PreparedStatement pstm = null;         ResultSet rs = null;         User user = null;         if (connection != null){             String sql = "select * from smbms_user where userCode = ?";             Object[] params = {userCode};             rs = BaseDao.execute(connection, pstm, rs, sql, params);             if (rs.next()){                 user = new User();                 user.setId(rs.getInt("id"));                 user.setUserCode(rs.getString("userCode"));                 user.setUserName(rs.getString("userName"));                 user.setUserPassword(rs.getString("userPassword"));                 user.setGender(rs.getInt("gender"));                 user.setBirthday(rs.getDate("birthday"));                 user.setPhone(rs.getString("phone"));                 user.setAddress(rs.getString("address"));                 user.setUserRole(rs.getInt("userRole"));                 user.setCreatedBy(rs.getInt("createdBy"));                 user.setCreationDate(rs.getTimestamp("creationDate"));                 user.setModifyBy(rs.getInt("modifyBy"));                 user.setModifyDate(rs.getTimestamp("modifyDate"));             }             BaseDao.closeResource(null, pstm, rs);         }         return user;     } }

3、service层，调用Dao层进行业务实现（用户登录操作）

        （1）编写业务层接口

package com.zhou.service.user; import com.zhou.pojo.User; public interface UserService {     //用户登录     public User login(String userCode, String password); }

        （2）编写业务层业务层实现类

package com.zhou.service.user; import com.zhou.dao.BaseDao; import com.zhou.dao.user.UserDao; import com.zhou.dao.user.UserDaoImpl; import com.zhou.pojo.User; import org.junit.Test; import java.sql.Connection; import java.sql.SQLException; public class UserServiceImpl implements UserService{     //业务层都会调用dao层，所以我们要引入Dao层     private UserDao userDao;     public UserServiceImpl(){         userDao = new UserDaoImpl();     }          public User login(String userCode, String password) {         Connection connection = null;         User user = null;                  try {             connection = BaseDao.getConnection();             // 通过业务层调用对应的具体的数据库操作             user = userDao.getLoginUser(connection, userCode);         } catch (SQLException e) {             throw new RuntimeException(e);         }finally {             BaseDao.closeResource(connection, null, null);         }         return user;     }     @Test     public void test(){         UserServiceImpl userService = new UserServiceImpl();         User admin = userService.login("wen", "1234567");         System.out.println(admin.getUserPassword());     } }

4、servlet层操作（接收用户页面参数，调用service层，转发视图）

package com.zhou.servlet.user; import com.zhou.pojo.User; import com.zhou.service.user.UserService; import com.zhou.service.user.UserServiceImpl; import com.zhou.util.Constants; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; public class LoginServlet extends HttpServlet {     // servlet:控制层，调用业务层代码     @Override     protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {         System.out.println("LoginServlet--start...");         // 获取用户名和密码         String userCode = req.getParameter("userCode");         String userPassword = req.getParameter("userPassword");         // 和数据库中的密码进行对比，调用业务层         UserService userService = new UserServiceImpl();         User user = userService.login(userCode, userPassword);// 这里已经把登录的人查出来了         if (user != null){ // 查有此人，可以登录             // 将用户的信息放到Session中             req.getSession().setAttribute(Constants.USER_SESSION, user);              // 跳转到主页             resp.sendRedirect("jsp/frame.jsp");         }else { // 查无此人，无法登录             // 转发回登录页面, 顺带提示他，用户名或密码错误             req.setAttribute("error", "用户名或密码错误");             req.getRequestDispatcher("login.jsp").forward(req, resp);         }     }     @Override     protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {         doGet(req, resp);     } }

5、filter层（过滤器层）

        （1）编写字符编码过滤器

package com.zhou.filter; import javax.servlet.*; import java.io.IOException; public class CharacterEncodingFilter implements Filter {     public void init(FilterConfig filterConfig) throws ServletException {     }     public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {         servletRequest.setCharacterEncoding("utf-8");         servletResponse.setCharacterEncoding("utf-8");         servletResponse.setContentType("text/html;charset=utf-8");         filterChain.doFilter(servletRequest, servletResponse);     }     public void destroy() {     } }

        （2）编写页面权限过滤器

                （配合用户退出功能做的，用户退出后，也就是session被清除了就不可以不登录就直接进一些网页）

package com.zhou.filter; import com.zhou.pojo.User; import com.zhou.util.Constants; import javax.servlet.*; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; public class SysFilter implements Filter {     public void init(FilterConfig filterConfig) throws ServletException {     }     public void doFilter(ServletRequest req, ServletResponse resp, FilterChain filterChain) throws IOException, ServletException {         HttpServletRequest request = (HttpServletRequest) req;         HttpServletResponse response = (HttpServletResponse) resp;         // 过滤器从session中获取用户，如果session被移除了，（LoginOutServlet）那就获取不到user了         User user = (User) request.getSession().getAttribute(Constants.USER_SESSION);         if (user == null){ // 已经被移除或者注销，或者未登录             response.sendRedirect("/smbms/error.jsp");         }else {             filterChain.doFilter(req, resp);         }     }     public void destroy() {     } }

6、别忘了servlet和filter要在web.xml里面注册