用户管理底层实现

当我们点击用户管理的时候。不是像修改密码一样单纯跳转到另一个页面，而是发出请求

点击密码修改：

点击用户管理：

 思路：

至少得查3张表

流程图

实现步骤：

1.导入分页的工具类（自己写的）

2.用户列表的导入

userlist.jsp分析：

 

 底下分页的实现：

一---获取用户数量

1. UserDao
2. UserDaoImpl

   // 根据用户名或者角色查询用户总数（最难理解的SQL)
       @Override
       public int getUserCount(Connection connection, String username, int userRole) throws SQLException {
           PreparedStatement pstm = null;
           ResultSet rs = null;
           int count = 0;
   
           if (connection != null) {
               StringBuffer sql = new StringBuffer();  // 保证线程安全还是用StringBuffer，所以如果需要对字符串进行修改推荐使用 StringBuffer。
               sql.append("select count(1) as count from smbms_user u, smbms_role r where u.userRole = r.id");
               ArrayList<Object> list = new ArrayList<>();// 存放我们的参数,万能解决方法
   
               if (!StringUtils.isNullOrEmpty(username)) {  // 前台传的用户名不为空，才执行下面的语句
                   sql.append(" and u.userName like ?"); // and前面空格不要丢，否则报错
                   list.add("%"+  username+ "%"); // 模糊查询 index:0
               }
   
               if (userRole > 0) {  // 如果前端输入要查询的userrole>0.追加sql语句
                   sql.append(" and u.userRole = ?");
                   list.add(userRole); // index:1
               }
   
               // 怎么把list转换为数组
               Object[] params = list.toArray();
               System.out.println("UserDaoImpl->getUserCount:" + sql.toString()); // 输出最后完整的sql语句
   
               rs = BaseDao.execute(connection, pstm, rs, sql.toString(), params);
               if (rs.next()) { // 链表的形式
                   count = rs.getInt("count");// 从结果集中获取最终的数量
               }
               BaseDao.closeResource(null,pstm,rs);
           }
           return count;
   
       }

3. UserService
4. UserserviceImpl

   // 查询记录数
       @Override
       public int getUserCount(String username, int userRole) {
           int count = 0;
           Connection connection = null;
           try {
               connection = BaseDao.getConnection(); // 连接数据库
               count = userDao.getUserCount(connection, username, userRole);
           } catch (SQLException e) {
               e.printStackTrace();
           } finally {
               BaseDao.closeResource(connection,null,null);
           }
   
         return count;
       }

二---获取用户列表：

1. UserDao

   // 通过条件查询userList
        List<User> getUserList(Connection connection, String userName, int userRole, int currentPageNo, int pageSize)throws Exception;

2. UserDaoImpl

   @Override
       public List<User> getUserList(Connection connection, String userName,int userRole,int currentPageNo, int pageSize)
               throws Exception {
           // TODO Auto-generated method stub
           PreparedStatement pstm = null;
           ResultSet rs = null;
           List<User> userList = new ArrayList<User>();
           if(connection != null){
               StringBuffer sql = new StringBuffer();
               sql.append("select u.*,r.roleName as userRoleName from smbms_user u,smbms_role r where u.userRole = r.id");
               List<Object> list = new ArrayList<Object>();
               if(!StringUtils.isNullOrEmpty(userName)){
                   sql.append(" and u.userName like ?");
                   list.add("%"+userName+"%");
               }
               if(userRole > 0){
                   sql.append(" and u.userRole = ?");
                   list.add(userRole);
               }
               sql.append(" order by creationDate DESC limit ?,?");
               currentPageNo = (currentPageNo-1)*pageSize;
               list.add(currentPageNo);
               list.add(pageSize);
   
               Object[] params = list.toArray();
               System.out.println("sql ----> " + sql.toString());
               rs = BaseDao.execute(connection, pstm, rs, sql.toString(), params);
               while(rs.next()){
                   User user = new User();
                   user.setId(rs.getInt("id"));
                   user.setUserCode(rs.getString("userCode"));
                   user.setUserName(rs.getString("userName"));
                   user.setGender(rs.getInt("gender"));
                   user.setBirthday(rs.getDate("birthday"));
                   user.setPhone(rs.getString("phone"));
                   user.setUserRole(rs.getInt("userRole"));
                   user.setUserRoleName(rs.getString("userRoleName"));
                   userList.add(user);
               }
               BaseDao.closeResource(null, pstm, rs);
           }
           return userList;
       }

3. UserService

   // 根据条件查询用户列表
        List<User> getUserList(String queryUserName, int queryUserRole, int currentPageNo, int pageSize);

4. UserServiceImpl

   @Override
       public List<User> getUserList(String queryUserName, int queryUserRole, int currentPageNo, int pageSize) {
           // TODO Auto-generated method stub
           Connection connection = null;
           List<User> userList = null;
           System.out.println("queryUserName ---- > " + queryUserName);
           System.out.println("queryUserRole ---- > " + queryUserRole);
           System.out.println("currentPageNo ---- > " + currentPageNo);
           System.out.println("pageSize ---- > " + pageSize);
           try {
               connection = BaseDao.getConnection();
               userList = userDao.getUserList(connection, queryUserName,queryUserRole,currentPageNo,pageSize);
           } catch (Exception e) {
               // TODO Auto-generated catch block
               e.printStackTrace();
           }finally{
               BaseDao.closeResource(connection, null, null);
           }
           return userList;
       }

 三---获取角色列表：

1:RoleDao

public interface RoleDao {
    // 获取角色列表
    public List<Role> getRoleList(Connection connection) throws Exception;

}

2:RoleDaoImpl

package com.mine.dao.role;

import com.mine.dao.BaseDao;
import com.mine.pojo.Role;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

public class RoleDaoImpl implements RoleDao{
    // 获取角色列表
    @Override
    public List<Role> getRoleList(Connection connection) throws Exception {
        PreparedStatement pstm = null;
        ResultSet resultSet = null;
        ArrayList<Role> roleList = new ArrayList<>();
        if(connection != null) {
            String sql = "select * from smbms_role";
            Object[] params = {};
            resultSet = BaseDao.execute(connection, pstm, resultSet, sql, params);
            while (resultSet.next()) {
                Role _role = new Role();
                _role.setId(resultSet.getInt("id"));
                _role.setRoleName(resultSet.getString("roleName"));
                _role.setRoleCode(resultSet.getString("roleCode"));
                roleList.add(_role);
            }
            BaseDao.closeResource(null,pstm,resultSet);
        }
        return roleList;

    }

}

3:RoleService

package com.mine.service.role;

import com.mine.pojo.Role;

import java.util.List;

public interface RoleService {
    public List<Role> getRoleList();
}

4:RoleServiceImpl

package com.mine.service.role;

import com.mine.dao.BaseDao;
import com.mine.dao.role.RoleDao;
import com.mine.dao.role.RoleDaoImpl;
import com.mine.pojo.Role;
import org.junit.Test;

import java.sql.Connection;
import java.util.List;

public class RoleServiceImpl implements RoleService{
    // 引入DAO
    private RoleDao roleDao;
    public RoleServiceImpl(){
        roleDao = new RoleDaoImpl();
    }

    @Override
    public List<Role> getRoleList() {
        Connection connection = null;
        List<Role> roleList = null;
        try {
            connection = BaseDao.getConnection();
            roleList = roleDao.getRoleList(connection);
        } catch (Exception e) {
            e.printStackTrace();
        }finally{
            BaseDao.closeResource(connection, null, null);
        }
        return roleList;
    }
    @Test
    public void test(){
        RoleServiceImpl roleService = new RoleServiceImpl();
        List<Role> roleList = roleService.getRoleList();
        for (Role role : roleList) {
            System.out.println(role.getRoleName());
        }

    }

}