JAVA web JSP SQL JS JDBC 前段 文件上传等综合 网络订餐小项目

package com.dw.lll.dao; import java.lang.reflect.Field; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.SQLException; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; public class BaseDao<T> { private String Driver = "com.mysql.jdbc.Driver"; private String url = "jdbc:mysql://127.0.0.1:3306/restrant"; private String user = "root"; private String password = "root"; protected Connection conn; protected PreparedStatement ps; protected ResultSet rs; /** * 获取连接对象 * * @throws Exception */ public void getConn() throws Exception { Class.forName(Driver); conn = DriverManager.getConnection(url, user, password); } /** * 关闭所有资源 */ public void closeAll() { try { if (conn != null) { conn.close(); } } catch (SQLException e) { e.printStackTrace(); } try { if (ps != null) { ps.close(); } } catch (SQLException e) { e.printStackTrace(); } try { if (rs != null) { rs.close(); } } catch (SQLException e) { e.printStackTrace(); } } /** * 增 删 改 操作 * * @param sql * @param s */ public void edit(String sql, String... s) { try { getConn(); ps = conn.prepareStatement(sql); for (int i = 0; i < s.length; i++) { System.out.println(s[i]); ps.setObject(i + 1, s[i]); } // ceshi System.out.println(sql); ps.executeUpdate(); } catch (Exception e) { e.printStackTrace(); } finally { closeAll(); } } /** * 查询单个 * * @param c * @param sql * @param s * @return */ public T selectOne(Class<T> c, String sql, String... s) { List<T> list = selectAllObject(c, sql, s); if (list.size() > 0) { return list.get(0); } else { return null; } } /** * 查询所有 * * @param c * @param sql * @param s * @return */ public List<T> selectAllObject(Class<T> c, String sql, String... s) { List<T> list = new ArrayList<T>(); try { getConn(); ps = conn.prepareStatement(sql); for (int i = 0; i < s.length; i++) { System.out.println(s[i]); ps.setObject(i + 1, s[i]); } // ceshi System.out.println(sql); rs = ps.executeQuery(); List<Map<String, Object>> datas = new ArrayList<Map<String, Object>>(); ResultSetMetaData rsmd = rs.getMetaData(); while (rs.next()) { Map<String, Object> data = new HashMap<String, Object>(); //注意列数 避免遗漏 for (int i = 1; i <= rsmd.getColumnCount(); i++) { data.put(rsmd.getColumnLabel(i), rs.getObject(i)); } datas.add(data); } for (int i = 0; i < datas.size(); i++) { Map<String, Object> data = datas.get(i); T t = c.newInstance(); for (String k : data.keySet()) { Field field = c.getDeclaredField(k); field.setAccessible(true); field.set(t, data.get(k)); } list.add(t); } } catch (Exception e) { e.printStackTrace(); } finally { closeAll(); } return list; } /** * 按条件查询是总数 * * @param sql * @param params * @return */ public int sumAll(String sql, String... params) { try { getConn(); ps = conn.prepareStatement(sql); for (int i = 0; i < params.length; i++) { ps.setObject(i + 1, params[i]); System.out.println(params[i]); } rs = ps.executeQuery(); while (rs.next()) { return rs.getInt(1); } } catch (Exception e) { e.printStackTrace(); } finally { closeAll(); } return 0; } }