package dao;import java.sql.*;public class BaseDao {    private static final String driver = "oracle.jdbc.driver.OracleDriver";    private static final String url = "jdbc:oracle:thin:@localhost:1521:ACCP";    private static final String uid = "scott";    private static final String pwd = "scott";    private static Connection con;    private static PreparedStatement pstmt;    /**     * 建立连接对象     * @return     */    public static Connection getConnection() {        try {            Class.forName(driver);            con = DriverManager.getConnection(url, uid, pwd);            return con;        } catch (ClassNotFoundException e) {            e.printStackTrace();        } catch (SQLException e) {            e.printStackTrace();        }        return null;    }    /**     * 关闭对象     * @param rs 数据集对象     */    public static void Close(ResultSet rs) {        if (rs != null) {            try {                rs.close();            } catch (SQLException e) {                // TODO Auto-generated catch block                e.printStackTrace();            }        }        if (pstmt != null) {            try {                pstmt.close();            } catch (SQLException e) {                // TODO Auto-generated catch block                e.printStackTrace();            }        }        if (con != null) {            try {                con.close();            } catch (SQLException e) {                // TODO Auto-generated catch block                e.printStackTrace();            }        }    }    /**     * 执行查询操作     * @param sql  查询的sql语句     * @param paras  查询的参数 Object[]数组     * @return 结果集     */    public static ResultSet ExecuteQuery(String sql, Object[] paras) {        getConnection();        try {            pstmt = con.prepareStatement(sql);            if (paras != null && paras.length > 0) {                for (int i = 0; i < paras.length; i++) {                    pstmt.setObject(i + 1, paras[i]);                }            }            ResultSet rs = pstmt.executeQuery();            return rs;        } catch (SQLException e) {            e.printStackTrace();            return null;        }    }    /**     * 执行增加、修改、删除操作     * @param sql  操作的sql语句     * @param paras  操作的参数     * @return 受影响的行数     */    public static int ExecuteUpdate(String sql, Object[] paras) {        getConnection();        try {            pstmt = con.prepareStatement(sql);            if (paras != null && paras.length > 0) {                for (int i = 0; i < paras.length; i++) {                    pstmt.setObject(i + 1, paras[i]);                }            }            int rs = pstmt.executeUpdate();            return rs;        } catch (SQLException e) {            e.printStackTrace();            return -1;        }    }}

package dao;import java.sql.*;import java.util.ArrayList;import java.util.List;import entities.Emp;public class empDao {    public List<Emp> GetEmpList() {        ResultSet rs = BaseDao.ExecuteQuery("select * from emp", null);                try {            List<Emp> list = new ArrayList<Emp>();            while (rs.next()) {                Emp e = new Emp();                e.setEmpno(rs.getInt("empno"));                e.setEname(rs.getString("ename"));                e.setJob(rs.getString("job"));                e.setMgr(rs.getInt("mgr"));                e.setHiredate(rs.getDate("hiredate"));                e.setSal(rs.getDouble("sal"));                e.setComm(rs.getDouble("comm"));                e.setDeptno(rs.getInt("deptno"));                list.add(e);            }            return list;        } catch (SQLException e) {            e.printStackTrace();            return null;        } finally {            BaseDao.Close(rs);        }    }}