jsp从mysql获取图片

<%@ page import="java.sql.*" %>
<%@ page contentType="image/jpeg" %>
<%
    // 获取图片ID参数
    int imageId = Integer.parseInt(request.getParameter("id"));

    // 连接数据库
    Connection conn = null;
    PreparedStatement pstmt = null;
    ResultSet rs = null;
    try {
        Class.forName("com.mysql.jdbc.Driver");
        conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydatabase", "username", "password");

        // 查询图片数据
        String sql = "SELECT data FROM images WHERE id = ?";
        pstmt = conn.prepareStatement(sql);
        pstmt.setInt(1, imageId);
        rs = pstmt.executeQuery();

        if (rs.next()) {
            // 输出图片数据
            byte[] imageData = rs.getBytes("data");
            out.write(imageData);
        } else {
            response.setStatus(HttpServletResponse.SC_NOT_FOUND);
        }
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        // 关闭资源
        try {
            if (rs != null) rs.close();
            if (pstmt != null) pstmt.close();
            if (conn != null) conn.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
%>

response.setHeader("Cache-Control", "no-cache, no-store, must-revalidate");
response.setHeader("Pragma", "no-cache");
response.setDateHeader("Expires", 0);