studentms/Tchengjidaoimplzh.java

package com.WR.StudentMS.dao.mysql;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import com.WR.StudentMS.dao.Tchengjidaolzh;
import com.WR.StudentMS.model.Registrationwmm;
import com.WR.StudentMS.model.Tchengjilzh;


public class Tchengjidaoimplzh implements Tchengjidaolzh {

	@Override
	public List<Tchengjilzh> findAll() {
		// TODO Auto-generated method stub
		String sql = "select id, stu_id, kecheng_id, chengji, xuenian, stu_xuehao, kecheng_name from t_chengji";		List<Tchengjilzh> list = new ArrayList<Tchengjilzh>();
		
		try(    
				Connection conn = DBHelper.getConnection();
				PreparedStatement pstmt = conn.prepareStatement(sql);
				ResultSet rs = pstmt.executeQuery(); ){
			//6.遍历结果集
			while(rs.next()) {
				
				Tchengjilzh p = new Tchengjilzh();
				
				p.setId(rs.getInt("id"));
				p.setStu_id(rs.getInt("stu_id"));
				p.setKecheng_id(rs.getInt("kecheng_id"));
				p.setChengji(rs.getInt("chengji"));
				p.setXuenian(rs.getString("xuenian"));
				p.setStu_xuehao(rs.getString("stu_xuehao"));
				p.setKecheng_name(rs.getString("kecheng_name"));
				
				
				list.add(p);			
			}
			
		}catch (SQLException e) {
			e.printStackTrace();
		}
		
		return list;	}

	@Override
	public Tchengjilzh findById(String tchengjilzh) {
		// TODO Auto-generated method stub
		Connection conn = null;
		PreparedStatement pstmt = null;
		ResultSet rs = null;
		
		String sql = "select id,stu_id,kecheng_id,chengji,xuenian,stu_xuehao,kecheng_name from t_chengji where id = ?";
		
		try {
			conn = DBHelper.getConnection(); 
			pstmt = conn.prepareStatement(sql);
			pstmt.setString(1, tchengjilzh);
			rs = pstmt.executeQuery();
			if (rs.next()) {
				Tchengjilzh p = new Tchengjilzh();
				
				p.setId(rs.getInt("id"));
				p.setStu_id(rs.getInt("stu_id"));
				p.setKecheng_id(rs.getInt("kecheng_id"));
				p.setChengji(rs.getInt("chengji"));
				p.setXuenian(rs.getString("xuenian"));
				p.setStu_xuehao(rs.getString("stu_xuehao"));
				p.setKecheng_name(rs.getString("kecheng_name"));
				
				return p;
			}
			
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			try {
				DBHelper.close(rs, pstmt, conn);
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		return null;
	}

	@Override
	public int create(Tchengjilzh tchengjilzh) {
		// TODO Auto-generated method stub
		String sql = "insert into t_chengji (id, stu_id, kecheng_id, chengji, xuenian, stu_xuehao, kecheng_name) values (?,?,?,?,?,?,?)";
		try(    
				Connection conn = DBHelper.getConnection();
				PreparedStatement pstmt = conn.prepareStatement(sql);
				 )
		{
			pstmt.setInt(1, tchengjilzh.getId());
			pstmt.setInt(2, tchengjilzh.getStu_id());
			pstmt.setInt(3, tchengjilzh.getKecheng_id());
			pstmt.setInt(4, tchengjilzh.getChengji());
			pstmt.setString(5, tchengjilzh.getXuenian());
			pstmt.setString(6, tchengjilzh.getStu_xuehao());
			pstmt.setString(7, tchengjilzh.getKecheng_name());
			
			int executeUpdate = pstmt.executeUpdate();
			System.out.printf("成功插入%d数据\n",executeUpdate);
			return executeUpdate;
		} catch (SQLException e) {
			// TODO: handle exception
			e.printStackTrace();
		}	
		return -1;
	}

	@Override
	public int modify(Tchengjilzh tchengjilzh) {
		// TODO Auto-generated method stub
		String sql = "UPDATE t_chengji SET id = ?, stu_id = ?, kecheng_id = ?, chengji = ?, xuenian = ?, stu_xuehao = ?, kecheng_name = ? WHERE id = ?";

	    try ( 
	        Connection conn = DBHelper.getConnection();
	        PreparedStatement pstmt = conn.prepareStatement(sql)
	    ) {
	        // 设置新值
	        pstmt.setInt(1, tchengjilzh.getId());
	        pstmt.setInt(2, tchengjilzh.getStu_id());
	        pstmt.setInt(3, tchengjilzh.getKecheng_id());
	        pstmt.setInt(4, tchengjilzh.getChengji());
	        pstmt.setString(5, tchengjilzh.getXuenian());
	        pstmt.setString(6, tchengjilzh.getStu_xuehao());
	        pstmt.setString(7, tchengjilzh.getKecheng_name());
	        // 设置旧的主键值，用于定位要更新的记录
	        pstmt.setInt(8, tchengjilzh.getId());	        
	        int affectedRows = pstmt.executeUpdate();
				System.out.printf("成功更新%d条数据。\n", affectedRows);
				return affectedRows;
			} catch (SQLException e) {
				e.printStackTrace();
				 return -1;
			}
	}

	@Override
	public int remove(Tchengjilzh tchengjilzh) {
	    String sql = "DELETE FROM t_chengji WHERE id = ?";
	    try (Connection conn = DBHelper.getConnection();
	         PreparedStatement pstmt = conn.prepareStatement(sql)) {
	        pstmt.setInt(1, tchengjilzh.getId());
	        int affectedRows = pstmt.executeUpdate();
	        if (affectedRows > 0) {
	            System.out.printf("成功删除%d条数据。\n", affectedRows);
	            return affectedRows; // 返回受影响的行数
	        } else {
	            System.out.println("未找到对应的记录或删除失败。");
	            return 0; // 没有记录被删除
	        }
	    } catch (SQLException e) {
	        e.printStackTrace();
	        return -1; // 发生异常
	    }
	}
}