session和cookie的使用，使用session显示用户，使用cookie实现记住密码

package com.tmg.util; import com.alibaba.druid.pool.DruidDataSourceFactory; import javax.sql.DataSource; import java.io.InputStream; import java.lang.reflect.Field; import java.sql.*; import java.util.ArrayList; import java.util.List; import java.util.Properties; public class JDBCUtils { static DataSource dataSource = null; static { Properties properties = new Properties(); InputStream is = JDBCUtils.class.getClassLoader().getResourceAsStream("durid.properties"); // InputStream resourceAsStream = JDBCUtils.class.getClassLoader().getResourceAsStream("durid.properties"); // System.out.println(resourceAsStream); try { properties.load(is); dataSource = DruidDataSourceFactory.createDataSource(properties); } catch (Exception e) { e.printStackTrace(); } } // 获取连接 public static Connection getConnection() { Connection connection = null; try { connection = dataSource.getConnection(); } catch (Exception e) { e.printStackTrace(); throw new RuntimeException("获取连接失败"); } return connection; } // 查询 public static <B> List<B> query(Class<B> clazz,String sql,Object... args) { Connection connection = null; PreparedStatement preparedStatement = null; ResultSet resultSet =null; try { connection = getConnection(); preparedStatement = connection.prepareStatement(sql); for (int i = 0; i < args.length; i++) { preparedStatement.setObject(i + 1, args[i]); } System.out.println("preparedStatement ="+preparedStatement); resultSet = preparedStatement.executeQuery(); List<B> list = new ArrayList<>(); ResultSetMetaData metaData = resultSet.getMetaData(); int counts = metaData.getColumnCount(); while (resultSet.next()){ B b = clazz.newInstance(); Field[] fields = clazz.getDeclaredFields(); for(int i=0;i<fields.length;i++){ String columnName = metaData.getColumnName(i + 1); Object object = resultSet.getObject(columnName); fields[i].setAccessible(true); fields[i].set(b,object); } list.add(b); } return list; } catch (SQLException e) { e.printStackTrace(); } catch (InstantiationException e) { e.printStackTrace(); } catch (IllegalAccessException e) { e.printStackTrace(); } finally { close(connection, preparedStatement,resultSet); } return null; } // 增删改 public static int update(String sql, Object... args) { Connection connection = null; PreparedStatement preparedStatement = null; try { connection = getConnection(); preparedStatement = connection.prepareStatement(sql); for (int i = 0; i < args.length; i++) { // System.out.println(args[i]); preparedStatement.setObject(i + 1, args[i]); } int i = preparedStatement.executeUpdate(); return 1; } catch (SQLException e) { e.printStackTrace(); return -1; } finally { close(connection, preparedStatement); } } // 关连接 public static void close(Connection conn, PreparedStatement ps) { try { if (ps != null) { try { ps.close(); } catch (SQLException e) { e.printStackTrace(); } // System.out.println("已关闭"); } if (conn != null) { try { conn.close(); } catch (SQLException e) { e.printStackTrace(); } // System.out.println("已关闭"); } } catch (Exception e) { e.printStackTrace(); } } public static void close(Connection conn, Statement ps) { try { if (ps != null) { try { ps.close(); } catch (SQLException e) { e.printStackTrace(); } // System.out.println("已关闭"); } if (conn != null) { try { conn.close(); } catch (SQLException e) { e.printStackTrace(); } // System.out.println("已关闭"); } } catch (Exception e) { e.printStackTrace(); } } public static void close(Connection conn, Statement ps, ResultSet rs) { try { if (rs != null) { try { rs.close(); } catch (SQLException e) { e.printStackTrace(); } } if (ps != null) { try { ps.close(); } catch (SQLException e) { e.printStackTrace(); } // System.out.println("已关闭"); } if (conn != null) { try { conn.close(); } catch (SQLException e) { e.printStackTrace(); } // System.out.println("已关闭"); } } catch (Exception e) { e.printStackTrace(); } } }