java使用三层架构实现电影购票系统

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.List;
 
public class BaseDao {
 
 public static final String DRIVER = "com.mysql.jdbc.Driver";
 public static final String URL = "jdbc:mysql://localhost:3306/tickets";
 
 // 加载驱动，只需加载一次
 static {
 try {
 Class.forName(DRIVER);
 } catch (ClassNotFoundException e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
 }
 }
 
 // 获得连接
 public Connection getConn() {
 Connection conn = null;
 
 try {
 conn = DriverManager.getConnection(URL, "root", "123456");
 } catch (SQLException e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
 }
 return conn;
 }
 
 // 关闭所有
 public void releaseAll(ResultSet rs, PreparedStatement pstmt, Connection conn) {
 
 try {
 if (rs != null) {
 rs.close();
 }
 if (pstmt != null) {
 pstmt.close();
 }
 if (conn != null) {
 conn.close();
 }
 } catch (SQLException e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
 }
 
 }
 
 // 增删改 封装
 public boolean operUpdate(String sql, List<Object> params) {
 Connection conn = null;
 PreparedStatement pstmt = null;
 int res = 0;
 
 // 获得与数据库的连接对象
 conn = getConn();
 
 try {
 
 pstmt = conn.prepareStatement(sql);
 
 if (params != null) {
 for (int i = 0; i < params.size(); i++) {
 
 pstmt.setObject(i + 1, params.get(i));
 
 }
 
 }
 // 增刪改的統一方法
 
 res = pstmt.executeUpdate();
 //返回的是sql在数据库中影响的行数
 } catch (SQLException e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
 } finally {
 releaseAll(null, pstmt, conn);
 }
 
 return res > 0 ? true : false;
 
 }
 
 public <T> List<T> operQuery(String sql, List<Object> params, Class<T> cls) throws Exception {
 Connection conn = null;
 PreparedStatement pstmt = null;
 ResultSet rs = null;
 List<T> list = new ArrayList<T>();
 conn = getConn();
 
 try {
 pstmt = conn.prepareStatement(sql);
 
 if (params != null) {
 for (int i = 0; i < params.size(); i++) {
 
 pstmt.setObject(i + 1, params.get(i));
 
 }
 
 }
 // 增刪改的統一方法
 
 rs = pstmt.executeQuery();
 ResultSetMetaData rsmd = rs.getMetaData();
 while (rs.next()) {
 T m = cls.newInstance();
 
 for (int i = 0; i < rsmd.getColumnCount(); i++) {
 String col_name = rsmd.getColumnName(i + 1);
 
 Object value = rs.getObject(col_name);
 
 Field field;
 
 field = cls.getDeclaredField(col_name);
 
 field.setAccessible(true);
 field.set(m, value);
 }
 list.add(m);
 }
 }
 
 catch (SQLException e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
 } finally {
 releaseAll(rs, pstmt, conn);
 }
 return list;
 
 }
 
}