diff --git a/ticketing-master/src/com/cn/dao/impl/TrainDaoImpl.java b/ticketing-master/src/com/cn/dao/impl/TrainDaoImpl.java
index 653cdd8..af378e1 100644
--- a/ticketing-master/src/com/cn/dao/impl/TrainDaoImpl.java
+++ b/ticketing-master/src/com/cn/dao/impl/TrainDaoImpl.java
@@ -1,239 +1,217 @@
-package com.cn.dao.impl;
+package com.cn.dao.impl; // 定义包名
 
-import java.sql.Connection;
-import java.sql.PreparedStatement;
-import java.sql.ResultSet;
-import java.sql.SQLException;
-import java.sql.Timestamp;
-import java.util.ArrayList;
-import java.util.List;
+import java.sql.*; // 导入SQL相关的类
+import java.util.*; // 导入集合相关的类
 
-import com.cn.dao.TrainDao;
-import com.cn.domain.Train;
-import com.cn.util.JDBCUtil;
+import com.cn.dao.TrainDao; // 导入TrainDao接口
+import com.cn.domain.Train; // 导入Train实体类
+import com.cn.util.JDBCUtil; // 导入JDBC工具类
 
 /**
- * 
- * @ClassName: TrainDaoImpl
- * @Description: TrainDao的实现类
- * @author: ljy
- * @date: 2019年9月14日 下午10:46:23
+ * TrainDao的实现类，提供列车数据访问操作。
  */
 public class TrainDaoImpl implements TrainDao {
+    private Connection conn = null; // 数据库连接对象
+    private PreparedStatement pstmt = null; // 预编译语句对象
+    private ResultSet rs = null; // 结果集对象
+
+    @Override
+    public int add(Train train) throws SQLException { // 添加列车信息的方法
+        String sql = "insert into train (trainnumber,startstation,endstation,starttime,endtime,price,seatnumber,addtime) values (?,?,?,?,?,?,?,?)";
+        conn = JDBCUtil.getConnection(); // 从JDBC工具类获取数据库连接
+        pstmt = conn.prepareStatement(sql); // 准备SQL插入语句
+        pstmt.setObject(1, train.getTrainNumber()); // 设置列车编号参数
+        pstmt.setObject(2, train.getStartStation()); // 设置起始站参数
+        pstmt.setObject(3, train.getEndStation()); // 设置终点站参数
+        pstmt.setObject(4, train.getStartTime()); // 设置起始时间参数
+        pstmt.setObject(5, train.getEndTime()); // 设置结束时间参数
+        pstmt.setObject(6, train.getPrice()); // 设置价格参数
+        pstmt.setObject(7, train.getSeatNumber()); // 设置座位数参数
+        pstmt.setObject(8, train.getAddTime()); // 设置添加时间参数
+        int recordNumber = pstmt.executeUpdate(); // 执行插入操作，并返回影响的行数
+        closeResources(); // 关闭数据库资源
+        return recordNumber;
+    }
+
+    @Override
+    public int delete(Integer trainId) throws SQLException { // 根据列车ID删除列车信息的方法
+        String sql = "delete from train where trainid=?";
+        conn = JDBCUtil.getConnection();
+        pstmt = conn.prepareStatement(sql);
+        pstmt.setObject(1, trainId); // 设置列车ID参数
+        int recordNumber = pstmt.executeUpdate(); // 执行删除操作，并返回影响的行数
+        closeResources();
+        return recordNumber;
+    }
+
+    @Override
+    public int update(Train train) throws SQLException { // 更新列车信息的方法
+        String sql = "update train set trainnumber=?,startstation=?,endstation=?,starttime=?,endtime=?,price=?,seatnumber=? where trainid=?";
+        conn = JDBCUtil.getConnection();
+        pstmt = conn.prepareStatement(sql);
+        pstmt.setObject(1, train.getTrainNumber()); // 设置列车编号参数
+        pstmt.setObject(2, train.getStartStation()); // 设置起始站参数
+        pstmt.setObject(3, train.getEndStation()); // 设置终点站参数
+        pstmt.setObject(4, train.getStartTime()); // 设置起始时间参数
+        pstmt.setObject(5, train.getEndTime()); // 设置结束时间参数
+        pstmt.setObject(6, train.getPrice()); // 设置价格参数
+        pstmt.setObject(7, train.getSeatNumber()); // 设置座位数参数
+        pstmt.setObject(8, train.getTrainId()); // 设置列车ID参数，用于更新条件
+        int recordNumber = pstmt.executeUpdate(); // 执行更新操作，并返回影响的行数
+        closeResources();
+        return recordNumber;
+    }
+
+    @Override
+    public List<Train> getAll() throws SQLException { // 获取所有列车信息的方法
+        String sql = "select * from train";
+        conn = JDBCUtil.getConnection();
+        pstmt = conn.prepareStatement(sql);
+        rs = pstmt.executeQuery(); // 执行查询操作
+        List<Train> list = new ArrayList<>(); // 创建列车信息列表
+        while (rs.next()) { // 遍历结果集
+            int trainId = rs.getInt("trainId"); // 获取列车ID
+            String trainNumber = rs.getString("trainNumber"); // 获取列车编号
+            String startStation = rs.getString("startStation"); // 获取起始站
+            String endStation = rs.getString("endStation"); // 获取终点站
+            String startTime = rs.getString("startTime"); // 获取起始时间
+            String endTime = rs.getString("endTime"); // 获取结束时间
+            int price = rs.getInt("price"); // 获取价格
+            int seatNumber = rs.getInt("seatNumber"); // 获取座位数
+            Timestamp addTime = rs.getTimestamp("addTime"); // 获取添加时间
+            Train train = new Train(trainId, trainNumber, startStation, endStation, startTime, endTime, price, seatNumber, addTime); // 创建列车对象
+            list.add(train); // 添加列车对象到列表
+        }
+        closeResources(); // 关闭数据库资源
+        return list; // 返回列车信息列表
+    }
+
+    @Override
+    public Train getById(Integer trainId) throws SQLException { // 根据列车ID获取列车信息的方法
+        String sql = "select * from train where trainid=?";
+        conn = JDBCUtil.getConnection();
+        pstmt = conn.prepareStatement(sql);
+        pstmt.setObject(1, trainId); // 设置列车ID参数
+        rs = pstmt.executeQuery(); // 执行查询操作
+        Train train = null; // 初始化列车对象
+        while (rs.next()) { // 遍历结果集
+            String trainNumber = rs.getString("trainNumber"); // 获取列车编号
+            String startStation = rs.getString("startStation"); // 获取起始站
+            String endStation = rs.getString("endStation"); // 获取终点站
+            String startTime = rs.getString("startTime"); // 获取起始时间
+            String endTime = rs.getString("endTime"); // 获取结束时间
+            int price = rs.getInt("price"); // 获取价格
+            int seatNumber = rs.getInt("seatNumber"); // 获取座位数
+            Timestamp addTime = rs.getTimestamp("addTime"); // 获取添加时间
+            train = new Train(trainId, trainNumber, startStation, endStation, startTime, endTime, price, seatNumber, addTime); // 创建列车对象
+        }
+        closeResources(); // 关闭数据库资源
+        return train; // 返回列车对象
+    }
+
+    @Override
+    public List<Train> getByTrainNumber(String trainNumber) throws SQLException { // 根据列车编号获取列车信息列表的方法
+        String sql = "select * from train where trainnumber=?";
+        conn = JDBCUtil.getConnection();
+        pstmt = conn.prepareStatement(sql);
+        pstmt.setObject(1, trainNumber); // 设置列车编号参数
+        rs = pstmt.executeQuery(); // 执行查询操作
+        List<Train> list = new ArrayList<>(); // 创建列车信息列表
+        while (rs.next()) { // 遍历结果集
+            int trainId = rs.getInt("trainId"); // 获取列车ID
+            String startStation = rs.getString("startStation"); // 获取起始站
+            String endStation = rs.getString("endStation"); // 获取终点站
+            String startTime = rs.getString("startTime"); // 获取起始时间
+            String endTime = rs.getString("endTime"); // 获取结束时间
+            int price = rs.getInt("price"); // 获取价格
+            int seatNumber = rs.getInt("seatNumber"); // 获取座位数
+            Timestamp addTime = rs.getTimestamp("addTime"); // 获取添加时间
+            Train train = new Train(trainId, trainNumber, startStation, endStation, startTime, endTime, price, seatNumber, addTime); // 创建列车对象
+            list.add(train); // 添加列车对象到列表
+        }
+        closeResources(); // 关闭数据库资源
+        return list; // 返回列车信息列表
+    }
+
+    @Override
+    public List<Train> getByStartEndStation(String startStation, String endStation, String startTime) throws SQLException { // 根据起始站、终点站和起始时间获取列车信息列表的方法
+        String sql = "select * from train where startStation=? and endStation=? and startTime like \"%\"?\"%\"";
+        conn = JDBCUtil.getConnection();
+        pstmt = conn.prepareStatement(sql);
+        pstmt.setObject(1, startStation); // 设置起始站参数
+        pstmt.setObject(2, endStation); // 设置终点站参数
+        pstmt.setObject(3, startTime); // 设置起始时间参数
+        rs = pstmt.executeQuery(); // 执行查询操作
+        List<Train> list = new ArrayList<>(); // 创建列车信息列表
+        while (rs.next()) { // 遍历结果集
+            int trainId = rs.getInt("trainId"); // 获取列车ID
+            String trainNumber = rs.getString("trainNumber"); // 获取列车编号
+            String endTime = rs.getString("endTime"); // 获取结束时间
+            int price = rs.getInt("price"); // 获取价格
+            int seatNumber = rs.getInt("seatNumber"); // 获取座位数
+            Timestamp addTime = rs.getTimestamp("addTime"); // 获取添加时间
+            Train train = new Train(trainId, trainNumber, startStation, endStation, startTime, endTime, price, seatNumber, addTime); // 创建列车对象
+            list.add(train); // 添加列车对象到列表
+        }
+        closeResources(); // 关闭数据库资源
+ 			return list; // 返回列车信息列表
+ 		}
+@Override
+public List<Train> getAllStartStation() throws SQLException { // 获取所有不同的起始站的方法
+    String sql = "select distinct startstation from train"; // SQL查询，选择不同的起始站
+    conn = JDBCUtil.getConnection(); // 从JDBC工具类获取数据库连接
+    pstmt = conn.prepareStatement(sql); // 准备SQL查询语句
+    rs = pstmt.executeQuery(); // 执行查询操作
+    List<Train> list = new ArrayList<>(); // 创建列车信息列表
+    while (rs.next()) { // 遍历结果集
+        String startStation = rs.getString("startStation"); // 获取起始站
+        Train train = new Train(); // 创建列车对象
+        train.setStartStation(startStation); // 设置列车对象的起始站
+        list.add(train); // 将列车对象添加到列表
+    }
+    closeResources(); // 关闭数据库资源
+    return list; // 返回列车信息列表
+}
 
-	private Connection conn = null;
-	private PreparedStatement pstmt = null;
-	private ResultSet rs = null;
-
-	@Override
-	public int add(Train train) throws SQLException {
-		String sql = "insert into train (trainnumber,startstation,endstation,starttime,endtime,price,seatnumber,addtime) values (?,?,?,?,?,?,?,?)";
-
-		conn = JDBCUtil.getConnection();
-		pstmt = conn.prepareStatement(sql);
-		pstmt.setObject(1, train.getTrainNumber());
-		pstmt.setObject(2, train.getStartStation());
-		pstmt.setObject(3, train.getEndStation());
-		pstmt.setObject(4, train.getStartTime());
-		pstmt.setObject(5, train.getEndTime());
-		pstmt.setObject(6, train.getPrice());
-		pstmt.setObject(7, train.getSeatNumber());
-		pstmt.setObject(8, train.getAddTime());
-
-		int recordNumber = pstmt.executeUpdate();
-		pstmt.close();
-		conn.close();
-		return recordNumber;
-	}
-
-	@Override
-	public int delete(Integer trainId) throws SQLException {
-		String sql = "delete from train where trainid=?";
-		conn = JDBCUtil.getConnection();
-		pstmt = conn.prepareStatement(sql);
-		pstmt.setObject(1, trainId);
-		int recordNumber = pstmt.executeUpdate();
-		pstmt.close();
-		conn.close();
-		return recordNumber;
-	}
-
-	/*
-	 * @Override public int update(Train train) throws SQLException { conn =
-	 * JDBCUtil.getConnection(); queryRunner = new QueryRunner(); int recordNumber =
-	 * queryRunner.update(conn,
-	 * "update train set trainnumber=?,startstation=?,endstation=?,starttime=?,endtime=?,price=?,seatnumber=?,addtime=? where trainid=?"
-	 * , train.getTrainNumber(),train.getStartStation(),train.getEndStation(),train.
-	 * getStartTime(),train.getEndTime(),train.getPrice(),train.getSeatNumber(),
-	 * train.getAddTime(),train.getTrainId()); conn.close(); return
-	 * recordNumber; }
-	 */
-
-	@Override
-	public int update(Train train) throws SQLException {
-		String sql = "update train set trainnumber=?,startstation=?,endstation=?,starttime=?,endtime=?,price=?,seatnumber=? where trainid=?";
-		conn = JDBCUtil.getConnection();
-		pstmt = conn.prepareStatement(sql);
-		pstmt.setObject(1, train.getTrainNumber());
-		pstmt.setObject(2, train.getStartStation());
-		pstmt.setObject(3, train.getEndStation());
-		pstmt.setObject(4, train.getStartTime());
-		pstmt.setObject(5, train.getEndTime());
-		pstmt.setObject(6, train.getPrice());
-		pstmt.setObject(7, train.getSeatNumber());
-		pstmt.setObject(8, train.getTrainId());
-
-		int recordNumber = pstmt.executeUpdate();
-		pstmt.close();
-		conn.close();
-		return recordNumber;
-	}
-
-	@Override
-	public List<Train> getAll() throws SQLException {
-		String sql = "select * from train";
-		conn = JDBCUtil.getConnection();
-		pstmt = conn.prepareStatement(sql);
-		rs = pstmt.executeQuery();
-		List<Train> list = new ArrayList<Train>();
-		while (rs.next()) {
-			int trainId = rs.getInt("trainId");
-			String trainNumber = rs.getString("trainNumber");
-			String startStation = rs.getString("startStation");
-			String endStation = rs.getString("endStation");
-			String startTime = rs.getString("startTime");
-			String endTime = rs.getString("endTime");
-			int price = rs.getInt("price");
-			int seatNumber = rs.getInt("seatNumber");
-			Timestamp addTime = rs.getTimestamp("addTime");
-			Train train = new Train(trainId, trainNumber, startStation, endStation, startTime, endTime, price,
-					seatNumber, addTime);
-			list.add(train);
-		}
-		rs.close();
-		pstmt.close();
-		conn.close();
-		return list;
-	}
-
-	@Override
-	public Train getById(Integer trainId) throws SQLException {
-		String sql = "select * from train where trainid=?";
-		conn = JDBCUtil.getConnection();
-		pstmt = conn.prepareStatement(sql);
-		pstmt.setObject(1, trainId);
-		rs = pstmt.executeQuery();
-		Train train = null;
-		while (rs.next()) {
-			String trainNumber = rs.getString("trainNumber");
-			String startStation = rs.getString("startStation");
-			String endStation = rs.getString("endStation");
-			String startTime = rs.getString("startTime");
-			String endTime = rs.getString("endTime");
-			int price = rs.getInt("price");
-			int seatNumber = rs.getInt("seatNumber");
-			Timestamp addTime = rs.getTimestamp("addTime");
-			train = new Train(trainId, trainNumber, startStation, endStation, startTime, endTime, price, seatNumber,
-					addTime);
-		}
-		rs.close();
-		pstmt.close();
-		conn.close();
-		return train;
-	}
-
-	@Override
-	public List<Train> getByTrainNumber(String trainNumber) throws SQLException {
-		String sql = "select * from train where trainnumber=?";
-		conn = JDBCUtil.getConnection();
-		pstmt = conn.prepareStatement(sql);
-		pstmt.setObject(1, trainNumber);
-		rs = pstmt.executeQuery();
-		List<Train> list = new ArrayList<Train>();
-		while (rs.next()) {
-			int trainId = rs.getInt("trainId");
-			String startStation = rs.getString("startStation");
-			String endStation = rs.getString("endStation");
-			String startTime = rs.getString("startTime");
-			String endTime = rs.getString("endTime");
-			int price = rs.getInt("price");
-			int seatNumber = rs.getInt("seatNumber");
-			Timestamp addTime = rs.getTimestamp("addTime");
-			Train train = new Train(trainId, trainNumber, startStation, endStation, startTime, endTime, price,
-					seatNumber, addTime);
-			list.add(train);
-		}
-		rs.close();
-		pstmt.close();
-		conn.close();
-		return list;
-	}
-
-	@Override
-	public List<Train> getByStartEndStation(String startStation, String endStation, String startTime)
-			throws SQLException {
-		String sql = "select * from train where startStation=? and endStation=? and startTime like \"%\"?\"%\"";
-		conn = JDBCUtil.getConnection();
-		pstmt = conn.prepareStatement(sql);
-		pstmt.setObject(1, startStation);
-		pstmt.setObject(2, endStation);
-		pstmt.setObject(3, startTime);
-		rs = pstmt.executeQuery();
-		List<Train> list = new ArrayList<Train>();
-		while (rs.next()) {
-			int trainId = rs.getInt("trainId");
-			String trainNumber = rs.getString("trainNumber");
-			String endTime = rs.getString("endTime");
-			int price = rs.getInt("price");
-			int seatNumber = rs.getInt("seatNumber");
-			Timestamp addTime = rs.getTimestamp("addTime");
-			Train train = new Train(trainId, trainNumber, startStation, endStation, startTime, endTime, price,
-					seatNumber, addTime);
-			list.add(train);
-		}
-		rs.close();
-		pstmt.close();
-		conn.close();
-		return list;
-	}
-
-	@Override
-	public List<Train> getAllStartStation() throws SQLException {
-		String sql = "select distinct startstation from train";
-		conn = JDBCUtil.getConnection();
-		pstmt = conn.prepareStatement(sql);
-		rs = pstmt.executeQuery();
-		List<Train> list = new ArrayList<Train>();
-		
-		while (rs.next()) {
-			String startStation = rs.getString("startStation");
-			Train train = new Train();
-			train.setStartStation(startStation);
-			list.add(train);
+@Override
+		public List<Train> getAllEndStation() throws SQLException { // 获取所有不同的终点站的方法
+    		String sql = "select distinct endstation from train"; // SQL查询，选择不同的终点站
+   	 		conn = JDBCUtil.getConnection(); // 从JDBC工具类获取数据库连接
+    		pstmt = conn.prepareStatement(sql); // 准备SQL查询语句
+    		rs = pstmt.executeQuery(); // 执行查询操作
+    		List<Train> list = new ArrayList<>(); // 创建列车信息列表
+    		while (rs.next()) { // 遍历结果集
+        		String endStation = rs.getString("endStation"); // 获取终点站
+        		Train train = new Train(); // 创建列车对象
+        		train.setEndStation(endStation); // 设置列车对象的终点站
+        		list.add(train); // 将列车对象添加到列表
+    		}
+    		closeResources(); // 关闭数据库资源
+    		return list; // 返回列车信息列表
 		}
-		rs.close();
-		pstmt.close();
-		conn.close();
-		return list;
-	}
 
-	@Override
-	public List<Train> getAllEndStation() throws SQLException {
-		String sql = "select distinct endstation from train";
-		conn = JDBCUtil.getConnection();
-		pstmt = conn.prepareStatement(sql);
-		rs = pstmt.executeQuery();
-		List<Train> list = new ArrayList<Train>();
-		while (rs.next()) {
-			String endStation = rs.getString("endStation");
-			Train train = new Train();
-			train.setEndStation(endStation);
-			list.add(train);
+		// 关闭数据库资源的方法
+		private void closeResources() {
+    		if (rs != null) {
+        		try {
+            		rs.close(); // 关闭结果集
+        		} catch (SQLException e) {
+            		e.printStackTrace();
+        		}
+    		}
+    		if (pstmt != null) {
+        		try {
+            		pstmt.close(); // 关闭预编译语句
+        		} catch (SQLException e) {
+            		e.printStackTrace();
+        		}
+    		}
+    		if (conn != null) {
+        		try {
+            		conn.close(); // 关闭数据库连接
+        		} catch (SQLException e) {
+            		e.printStackTrace();
+        		}
+    		}
 		}
-		rs.close();
-		pstmt.close();
-		conn.close();
-		return list;
-	}
-
-}
+}
\ No newline at end of file