基于java的聊天室（webjsp）

package org.db; import java.sql.*; public class DataBase { private Connection conn = null; private Statement stmt; public DataBase() throws SQLException { String user = "sa"; String pass = "";// 成员方法 String url = "jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=lab"; try { // 加载JDBC驱动程序 Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver"); } catch (ClassNotFoundException e) { System.out.println("加载驱动器类时出现异常"); } try { conn = DriverManager.getConnection(url, user, pass); // 建立数据库连接 stmt = conn.createStatement(); // 创建Statement语句 } catch (SQLException e) { System.out.println(e); } } public User checkUser(String username, String password) { ResultSet rs = null; String sql = "select * from [user] where name = '" + username + "' and password = '" + password + "'"; User u = null; try { rs = stmt.executeQuery(sql); if (rs.next()) { u = new User(rs.getString(1),rs.getString(2),rs.getString(3)); return u; } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return u; } public String regUser(String username , String password ) { ResultSet rs = null; String sql = "select * from [user] where name = '" + username+ "'"; int i; try { rs = stmt.executeQuery(sql); if (rs.next()) return "用户已经被注册"; else { sql = "insert into user values('"+username+"','"+password+"')"; i = stmt.executeUpdate(sql); if(i == 1) return "用户注册成功"; else return "用户注册失败"; } } catch (SQLException e) { // TODO Auto-generated catch block return "用户注册失败,失败原因："+e; } } public void close() { try { if (stmt != null) stmt.close(); if(conn!=null) conn.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }