studentms/ZhuanyeDaoImpWR.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.ZhuanyeDaoWR;
import com.WR.StudentMS.model.ZhuanyeWR;

public class ZhuanyeDaoImpWR implements ZhuanyeDaoWR {

	@Override
	public List<ZhuanyeWR> findAll() {
		// TODO 自动生成的方法存根
		String sql = "select id,name,jieshao from t_zhuanye";
        List<ZhuanyeWR> list = new ArrayList<ZhuanyeWR>();
        try(
                Connection conn = DBHelper.getConnection();//TODO
                PreparedStatement pstmt = conn.prepareStatement(sql);
                ResultSet rs = pstmt.executeQuery(); ){
            while(rs.next()) {
            	ZhuanyeWR zhuanyewr = new ZhuanyeWR();
            	zhuanyewr.setId(rs.getInt("id"));
            	zhuanyewr.setName(rs.getString("name"));
            	zhuanyewr.setJieshao(rs.getString("jieshao"));
                list.add(zhuanyewr);
            }
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
	return list;
	}

	@Override
	public ZhuanyeWR findById(int id) {
		// TODO 自动生成的方法存根
		Connection conn = null;
        PreparedStatement pstmt = null;
        ResultSet rs = null;

        try {
            conn = DBHelper.getConnection();
            String sql = "select id,name,jieshao from t_zhuanye where id = ?";
            pstmt = conn.prepareStatement(sql);
            pstmt.setInt(1, id);
            rs = pstmt.executeQuery();
            if (rs.next()) {
            	ZhuanyeWR zhuanyewr = new ZhuanyeWR();
            	zhuanyewr.setId(rs.getInt("id"));
            	zhuanyewr.setName(rs.getString("name"));
            	zhuanyewr.setJieshao(rs.getString("jieshao"));
                return zhuanyewr;
            }

        } 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(ZhuanyeWR zhuanyewr) {
	    // 检查ID是否已存在
	    String checkSql = "SELECT COUNT(*) FROM t_zhuanye WHERE id = ?";
	    try (Connection conn = DBHelper.getConnection();
	         PreparedStatement checkStmt = conn.prepareStatement(checkSql)) {
	        checkStmt.setInt(1, zhuanyewr.getId());
	        ResultSet rs = checkStmt.executeQuery();
	        if (rs.next() && rs.getInt(1) > 0) {
	            // 如果ID已存在，则返回提示
	            return 0; // 0通常表示操作没有影响任何行
	        }
	    } catch (SQLException e) {
	        e.printStackTrace();
	        return -1;
	    }

	    // 继续执行插入操作
	    String sql = "INSERT INTO t_zhuanye (id, name, jieshao) VALUES (?, ?, ?)";
	    try (Connection conn = DBHelper.getConnection();
	         PreparedStatement pstmt = conn.prepareStatement(sql)) {
	        pstmt.setInt(1, zhuanyewr.getId());
	        pstmt.setString(2, zhuanyewr.getName());
	        pstmt.setString(3, zhuanyewr.getJieshao());
	        int executeUpdate = pstmt.executeUpdate();
	        return executeUpdate;
	    } catch (SQLException e) {
	        e.printStackTrace();
	        return -1;
	    }
	}

	@Override
	public int remove(ZhuanyeWR zhuanyewr) {
		String sql = "DELETE FROM t_zhuanye WHERE id = ?";
		try (
	        Connection conn = DBHelper.getConnection();
	        PreparedStatement pstmt = conn.prepareStatement(sql)
	    ) {
	        pstmt.setInt(1, zhuanyewr.getId()); // 假设stu_id是外键，与专业ID相关联
	        int affectedRows = pstmt.executeUpdate();
	        System.out.printf("删除%d条数据。\n", affectedRows);
	        return affectedRows;
	    } catch (SQLException e) {
	        e.printStackTrace();
	        return -1;
	    }
	}
	@Override
	public int modify(ZhuanyeWR zhuanyewr) {
	    String sql = "UPDATE t_zhuanye SET name = ?, jieshao = ? WHERE id = ?";
	    try (
	        Connection conn = DBHelper.getConnection();
	        PreparedStatement pstmt = conn.prepareStatement(sql);
	    ) {
	        pstmt.setString(1, zhuanyewr.getName());
	        pstmt.setString(2, zhuanyewr.getJieshao());
	        pstmt.setInt(3, zhuanyewr.getId());
	        int affectedRows = pstmt.executeUpdate();
	        System.out.printf("更新%d条数据。\n", affectedRows);
	        return affectedRows;
	    } catch (SQLException e) {
	        // 可以在这里添加更详细的错误处理
	        e.printStackTrace();
	        return -1;
	    }
	}

}