分别使用Statement和PreparedStatement对数据库进行操作

// 插入操作
    public void insert(Vector<Person> vt) {
        PreparedStatement ps = null;
        try {
            dbHelper = new DBHelper();
            conn = dbHelper.getConn();
            conn.setAutoCommit(false);// 首先把Auto commit设置为false,不让它自动提交
            String sql = "insert into " + Constant.TABLE_NAME
                    + " values (?,?,?,?,?,?)";
            ps = conn.prepareStatement(sql);
            for (Person person : vt) {
                ps.setInt(1, person.getId());
                ps.setString(2, person.getName());
                ps.setString(3, person.getAge());
                ps.setString(4, person.getSex());
                ps.setString(5, person.getTelNum());
                ps.setString(6, person.getAddress());
                ps.addBatch();
            }
            ps.executeBatch();
            conn.commit();// 进行手动提交（commit）
            conn.setAutoCommit(true);// 提交完成后回复现场将Auto commit,还原为true
            System.out.println("添加成功");
        } catch (SQLException e) {
            e.printStackTrace();
            try {// 若出现异常，对数据库中所有已完成的操作全部撤销，则回滚到事务开始状态
                if (!conn.isClosed()) {
                    // 当异常发生执行catch中SQLException时，记得要rollback(回滚)；
                    conn.rollback();
                    System.out.println("插入失败，回滚！");
                    conn.setAutoCommit(true);
                }
            } catch (SQLException e1) {
                e1.printStackTrace();
            }
        } finally {
            try {
                ps.close();
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }

        }
    }

    // 查询操作
    public Vector<Person> selectAll() {
        Vector<Person> vt = new Vector<Person>();
        try {
            dbHelper = new DBHelper();
            conn = dbHelper.getConn();
            String sql = "select * from " + Constant.TABLE_NAME;
            Statement stmt = conn.createStatement();
            ResultSet rs = stmt.executeQuery(sql);
            while (rs.next()) {
                Person person = new Person();
                person.setId(rs.getInt(1));
                person.setName(rs.getString(2));
                person.setAge(rs.getString(3));
                person.setSex(rs.getString(4));
                person.setTelNum(rs.getString(5));
                person.setAddress(rs.getString(6));
                vt.add(person);
            }
            stmt.close();
            rs.close();
            conn.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return vt;

    }

    // 删除所有
    public void deleteAll() {
        try {
            dbHelper = new DBHelper();
            conn = dbHelper.getConn();
            String sql = "truncate table " + Constant.TABLE_NAME;
            PreparedStatement ps = conn.prepareStatement(sql);
            ps.executeUpdate();
            ps.close();
            conn.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }