Java Web实现登陆注册页面前端与后台数据连接（代码+sql文件）

package com.teach.commons; import java.beans.BeanInfo; import java.beans.IntrospectionException; import java.beans.Introspector; import java.beans.PropertyDescriptor; import java.io.Serializable; import java.lang.reflect.Field; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import java.util.ArrayList; import java.util.Date; import java.util.HashMap; import java.util.List; import java.util.Map; import java.util.Properties; import com.teach.annotations.Name; import com.teach.annotations.Id; /** * jdbc工具类 * * @author J.L.Zhou * */ public class DBUtil { /** * 构造方法私有化，无例模式 */ private DBUtil() { } private static String url; private static String user; private static String pwd; static { try { Properties config = new Properties(); config.load(Thread.currentThread().getContextClassLoader().getResourceAsStream("config.properties")); url = config.getProperty("jdbc.url"); user = config.getProperty("jdbc.username"); pwd = config.getProperty("jdbc.password"); String className = config.getProperty("jdbc.driverClassName"); Class.forName(className); } catch (Exception e) { e.printStackTrace(); System.exit(0); } } /** * * @return * @throws SQLException */ public static Connection getConnection() throws SQLException { return DriverManager.getConnection(url, user, pwd); } /** * 关闭jdbc对象 * * @param conn * @param stmt */ public static void close(Connection conn, Statement stmt) { try { stmt.close(); } catch (Exception ex) { } try { conn.close(); } catch (Exception ex) { } } /** * 关闭jdbc对象 * * @param conn * @param stmt * @param rs */ public static void close(Connection conn, Statement stmt, ResultSet rs) { try { rs.close(); } catch (Exception ex) { } close(conn, stmt); } /** * 执行sql语句 * * @param sql * @param args * @throws SQLException */ public static void execute(String sql, Object... args) throws SQLException { Connection conn = null; PreparedStatement pstmt = null; try { conn = getConnection(); pstmt = conn.prepareStatement(sql); setParams(pstmt, args); pstmt.executeUpdate(); } finally { close(conn, pstmt); } } /** * 获取一个对象 * * @param sql * @param cls * @param args * @return * @throws SQLException */ public static <T> T get(String sql, Class<T> cls, Object... args) throws SQLException { Connection conn = null; PreparedStatement pstmt = null; ResultSet rs = null; try { conn = getConnection(); pstmt = conn.prepareStatement(sql); setParams(pstmt, args); rs = pstmt.executeQuery(); if (rs.next()) { T t = load(rs, cls); if (rs.next()) { throw new SQLException("发现的记录>1"); } else { return t; } } else { throw new SQLException("没有发现一条记录"); } } finally { close(conn, pstmt, rs); } } public static Map<String,Object> getMap(String sql, Object... args) throws SQLException { Connection conn = null; PreparedStatement pstmt = null; ResultSet rs = null; try { conn = getConnection(); pstmt = conn.prepareStatement(sql); setParams(pstmt, args); rs = pstmt.executeQuery(); if (rs.next()) { Map<String,Object> t = load(rs); if (rs.next()) { throw new SQLException("发现的记录>1"); } else { return t; } } else { throw new SQLException("没有发现一条记录"); } } finally { close(conn, pstmt, rs); } } /** * 查询数据库获取结果集的第一行第一列的数据 * * @param sql * @param args * @return * @throws SQLException */ public static String getString(String sql, Object... args) throws SQLException { Connection conn = null; PreparedStatement pstmt = null; ResultSet rs = null; try { conn = getConnection(); pstmt = conn.prepareStatement(sql); setParams(pstmt, args); rs = pstmt.executeQuery(); if (rs.next()) { return rs.getString(1); } else { throw new SQLException("没有发现一条记录"); } } finally { close(conn, pstmt, rs); } } /** * 查询数据库获取结果集的第一行第一列的数据 * * @param sql * @param args * @return * @throws SQLException */ public static long getLong(String sql, Object... args) throws SQLException { Connection conn = null; PreparedStatement pstmt = null; ResultSet rs = null; try { conn = getConnection(); pstmt = conn.prepareStatement(sql); setParams(pstmt, args); rs = pstmt.executeQuery(); if (rs.next()) { return rs.getLong(1); } else { throw new SQLException("没有发现一条记录"); } } finally { close(conn, pstmt, rs); } } /** * 获取对象列表 * * @param sql * @param cls * @param args * @return * @throws SQLException */ public static <T> List<T> list(String sql, Class<T> cls, Object... args) throws SQLException { Connection conn = null; PreparedStatement pstmt = null; ResultSet rs = null; try { conn = getConnection(); pstmt = conn.prepareStatement(sql); setParams(pstmt, args); rs = pstmt.executeQuery(); List<T> list = new ArrayList<T>(); while (rs.next()) { list.add(load(rs, cls)); } return list; } finally { close(conn, pstmt, rs); } } public static List<Map<String,Object>> listMap(String sql, Object... args) throws SQLException { Connection conn = null; PreparedStatement pstmt = null; ResultSet rs = null; try { conn = getConnection(); pstmt = conn.prepareStatement(sql); setParams(pstmt, args); rs = pstmt.executeQuery(); List<Map<String,Object>> list = new ArrayList<Map<String,Object>>(); while (rs.next()) { list.add(load(rs)); } return list; } finally { close(conn, pstmt, rs); } } /** * 设置预编译的语句的所有参数 * * @param pstmt * @param args * @throws SQLException */ public static void setParams(PreparedStatement pstmt, Object... args) throws SQLException { for (int i = 0; i < args.length; i++) { setParams(pstmt, i + 1, args[i]); } } /** * 设置预编译的语句的一个参数 * * @param pstmt * @param index * @param value * @throws SQLException */ public static void setParams(PreparedStatement pstmt, int index, Object value) throws SQLException { if (value == null) { pstmt.setObject(index, null); } else if (value instanceof Date) { Date d = (Date) value; pstmt.setTimestamp(index, new java.sql.Timestamp(d.getTime())); } else { pstmt.setObject(index, value); } } @SuppressWarnings("unchecked") public static <T> T load(ResultSet rs, Class<T> cls) throws SQLException { Object obj = null; try { obj = cls.newInstance(); } catch (Exception e) { throw new SQLException("调用无参构造方法实例化错误：" + cls.getName(), e); } for (PropertyDescriptor prop : getPropertyDescriptors(cls)) { if (prop.getName().equals("class")) { continue; } String columnName = getColumnName(cls, prop); try { Object value = null; try { value = rs.getObject(columnName); } catch (Exception ex) { // 警告，字段不存在 } if (value != null) { if (prop.getPropertyType() == Integer.class) { value = rs.getInt(columnName); } else if (prop.getPropertyType() == Character.class) { value = rs.getString(columnName).charAt(0); } else if (prop.getPropertyType() == Date.class) {