基于控制台的通讯录管理系统

package com.maker.address.dao; import java.sql.Connection; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import java.util.ArrayList; import com.maker.address.entity.User; import com.maker.address.util.DBUtil; /** * dao层处理对数据库的操作 * @author Administrator * */ public class UserDao { //新增用户 public boolean add(User user) { // TODO Auto-generated method stub String sql = "insert into user(no,name,phone,qq,email) values ("+user.getNo()+",'"+user.getName()+"','"+user.getPhone()+"','"+user.getQQ()+"','"+user.getEmail()+"')"; Connection conn = DBUtil.getConn(); Statement state = null; int num = 0; System.out.println(sql); try { state = conn.createStatement(); num = state.executeUpdate(sql); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } finally { DBUtil.close(state, conn); } return num > 0; } //查询所有用户 public ArrayList getAll() { // TODO Auto-generated method stub String sql = "select * from user"; Connection conn = DBUtil.getConn(); Statement state = null; ArrayList<User> list = new ArrayList<>(); ResultSet rs = null; try { state = conn.createStatement(); rs = state.executeQuery(sql); while(rs.next()){ //结果集中有数据 代表查询出来有数据 //创建user对象，将数据存入到对象集合中 User user = new User(); user.setNo(rs.getInt("no")); user.setName(rs.getString("name")); user.setPhone(rs.getString("phone")); user.setQQ(rs.getString("qq")); user.setEmail(rs.getString("email")); list.add(user); } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } finally { DBUtil.close(rs,state, conn); } return list; } //按照编号查询用户 public User queryByNo(int no) { // TODO Auto-generated method stub String sql = "select * from user where no="+no; Connection conn = DBUtil.getConn(); Statement state = null; User user = null; ResultSet rs = null; try { state = conn.createStatement(); rs = state.executeQuery(sql); while(rs.next()){ user = new User(); //结果集中有数据 代表查询出来有数据 //创建user对象，将数据存入到对象集合中 user.setNo(rs.getInt("no")); user.setName(rs.getString("name")); user.setPhone(rs.getString("phone")); user.setQQ(rs.getString("qq")); user.setEmail(rs.getString("email")); } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } finally { DBUtil.close(rs,state, conn); } return user; } //删除用户按照编号 public boolean remove(User user) { // TODO Auto-generated method stub String sql = "delete from user where no = '"+user.getNo()+"'"; Connection conn = DBUtil.getConn(); Statement state = null; int num = 0; try { state = conn.createStatement(); num = state.executeUpdate(sql); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } finally { DBUtil.close(state, conn); } return num > 0; } //修改用户按照编号修改 public boolean updateUser(User user) { // TODO Auto-generated method stub String sql = "update user set name='"+user.getName()+"',phone='"+user.getPhone()+"',qq='"+user.getQQ()+"',email='"+user.getEmail()+"' where no = "+user.getNo(); Connection conn = DBUtil.getConn(); Statement state = null; int num = 0; try { state = conn.createStatement(); num = state.executeUpdate(sql); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } finally { DBUtil.close(state, conn); } return num > 0; } }