JDBC数据源从bean获取空值，抛出java.lang.NullPointerException

数据源未获取任何值。dataSource.getConnection抛出java.lang.NullPointerException

servlet-context.xml

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不要创建dao的新实例，从上下文中使用on。你可能正在某处做一辆新车。你是对的。我没有使用上下文中的实例

public class VehicleDaoImpl implements VehicleDao {
    private DataSource dataSource;

    public void setDataSource(DataSource dataSource1) {
        this.dataSource = dataSource1;
    }

    public void insert(Vehicle vehicle) {
        String sql = "INSERT INTO Vehicle (VEHICLE_NO, COLOR, WHEEL, SEAT) "
                + "VALUES (?, ?, ?, ?)";
                Connection conn = null;
                try {
                conn = dataSource.getConnection();
                PreparedStatement ps = conn.prepareStatement(sql);
                ps.setString(1, "gaurav");
                ps.setString(2, "rai");
                ps.setInt(3, 4);
                ps.setInt(4, 7);
                ps.executeUpdate();
                ps.close();
                } catch (SQLException e) {
                throw new RuntimeException(e);
                } finally {
                if (conn != null) {
                try {
                conn.close();
                } catch (SQLException e) {}
                }
                }
    }

    @Override
    public void update(Vehicle vehicle) { ... }

    @Override
    public void delete(Vehicle vehicle) { ... }

    @Override
    public Vehicle findByVehicleNo(String vehicleNo) {
        return null;
    }

}