Question

的index.jsp 这是我的jsp代码

 <%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>
 <%@ taglib prefix="sql" uri="http://java.sun.com/jsp/jstl/sql"%>
 <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
 <head>
<title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">    
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
</head>
       <sql:setDataSource var="webappDataSource" driver="com.mysql.jdbc.Driver" url="jdbc:mysql://localhost/bharatwellness"user="root" password="naveen" />
    <sql:query dataSource="${webappDataSource}" sql="select * from individaulpartner " var="result" />

    <table width="100%" border="1">
     <c:forEach var="row" items="${result.rows}">
       <tr>
        <td>${row.id}</td>
        <td>${row.fname}</td>
        <td>
           <img src="${pageContext.servletContext.contextPath }/ImageServlet?id=${row.id}" />
        </td>
        <td>
        <a href="${pageContext.servletContext.contextPath }/ImageServlet?id=${row.id}" />certificate</a>
        </td>
      </tr>
    </c:forEach>
    </table>
   </body>
 </html>

ImageGetTest.java 这是我的servlet代码

   package com.server.servlet;
   import java.io.IOException;
   import java.sql.*;
   import javax.servlet.*;
   import javax.servlet.http.HttpServlet;
   import javax.servlet.http.HttpServletRequest;
   import javax.servlet.http.HttpServletResponse;



  public class ImageServlet extends HttpServlet {
   protected void doGet(HttpServletRequest request, HttpServletResponse response)
 throws ServletException, IOException {

  final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
  final String DB_URL = "jdbc:mysql://localhost/mydatabase";
  final String User = "root";
  final String Password = "password";
  try {
    Class.forName(JDBC_DRIVER);
   Connection conn = DriverManager.getConnection(DB_URL, User, Password);

    PreparedStatement stmt = conn.prepareStatement("select * from usertable where  id=?");
   stmt.setLong(1, Long.valueOf(request.getParameter("id")));
   ResultSet rs = stmt.executeQuery();
   if (rs.next()) {
    response.getOutputStream().write(rs.getBytes("image"));
    response.getOutputStream().write(rs.getBytes("certificate1"));
   }
   conn.close();
  } catch (Exception e) {
  e.printStackTrace();
  }
 }

}

这是我从中获取数据的表格 enter image description here

我只能为一个ID显示单个图片或单个证书。如何在jsp页面上显示所有文件。请帮帮我......

Answer 1

您需要为每个单独的图像调用Sevlet。所以在你的JSP中你需要做类似的事情：

<td>
   <img src="${pageContext.servletContext.contextPath }/ImageServlet?id=${row.id}&name=image" />
   <img src="${pageContext.servletContext.contextPath }/ImageServlet?id=${row.id}&name=certificate" />
</td>

并在您的Servlet中检查附加的“name”参数以确定要发回的图像：

   if (rs.next()) {
    if(request.getParameter("name").equals("image")
        response.getOutputStream().write(rs.getBytes("image"));
    }else{
        response.getOutputStream().write(rs.getBytes("certificate1"));
    }
   }

所有这一切的问题在于它不是动态的。为了使它能够处理给定实体的任意数量的图像，您需要在处理JSP时了解可用的图像，并且有一个循环，它将为每个图像生成<img/>标记，并使用必要的参数。

这也可能涉及一些数据库更新：图像与相应的用户进入带有FK的不同表格。

img_id  user_id     image_data
1       1           bytes
2       1           bytes
3       1           bytes 
4       1           bytes

现在，您将获得相关用户的图像ID句柄，并通过将id传递给Servlet来逐个加载它们。

如何在jsp servlet中从数据库中获取相同id的多个图像

1 个答案: