Java BaseDao

BaseDao类:

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;

        }

    }

}

 

调用：

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);

        }

    }

}