用户管理系统——java

package dao.select; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; import java.util.List; import dao.BaseDAO; import bean.User; public class SelectDAO extends BaseDAO{ //查询并返回User类实例 public User select(User user){ Connection con = super.getCon(); String sql = "select * from users where name = ? and password = ?"; try { PreparedStatement ps = con.prepareStatement(sql); ps.setString(1, user.getName()); ps.setString(2, user.getPassword()); ResultSet rs = ps.executeQuery(); while(rs.next()){ user.setID(rs.getInt(1)); user.setName(rs.getString(2)); user.setPassword(rs.getString(3)); user.setMail(rs.getString(4)); user.setPower(rs.getString(5)); } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return user; } //查询全部用户信息 public List<User> selectAll(){ List<User> users = new ArrayList<User>(); Connection con = super.getCon(); String sql ="select * from users"; try { PreparedStatement ps =con.prepareStatement(sql); ResultSet rs = ps.executeQuery(); while(rs.next()){ User user = new User(); user.setID(rs.getInt(1)); user.setName(rs.getString(2)); user.setPassword(rs.getString(3)); user.setMail(rs.getString(4)); user.setPower(rs.getString(5)); users.add(user); } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return users; } //根据用户姓名查询 public List<User> selectName(String name){ List<User> users = new ArrayList<User>(); Connection con = super.getCon(); String sql ="select * from users where name like ?"; try { PreparedStatement ps =con.prepareStatement(sql); ps.setString(1, "%"+name+"%"); ResultSet rs = ps.executeQuery(); while(rs.next()){ User user = new User(); user.setID(rs.getInt(1)); user.setName(rs.getString(2)); user.setPassword(rs.getString(3)); user.setMail(rs.getString(4)); user.setPower(rs.getString(5)); users.add(user); } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return users; } //根据id 查询 public List<User> selectID(int id){ List<User> users = new ArrayList<User>(); Connection con = super.getCon(); String sql ="select * from users where id=?"; try { PreparedStatement ps =con.prepareStatement(sql); ps.setInt(1, id); ResultSet rs = ps.executeQuery(); while(rs.next()){ User user = new User(); user.setID(rs.getInt(1)); user.setName(rs.getString(2)); user.setPassword(rs.getString(3)); user.setMail(rs.getString(4)); user.setPower(rs.getString(5)); users.add(user); } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return users; } public void loop(List<User> users){ Collections.sort(users, new Comparator<User>() { @Override public int compare(User o1, User o2) { // TODO Auto-generated method stub return o1.getID()-o2.getID(); } }); for(User user:users){ System.out.print(user.getID()+" "); System.out.print(user.getName()+" "); System.out.print(user.getPassword()+" "); System.out.print(user.getMail()+" "); if(user.getPower().equals("normal")){ System.out.println("普通用户"); }else{ System.out.println("管理员"); } } } }