Question

我试图通过（using this）在jsp页面中显示blob图像，但是我收到错误：

javax.servlet.ServletException: java.sql.SQLException: Column '2' not found.

我的表是：

create table upload_image
(
    iImageID int AUTO_INCREMENT primary key,
    bImage longblob
);

代码： uploadimage.jsp

<%@ page language="java"  errorPage="" %>
<html>
<head>
<title>Image insert into database</title>
</head>

<body>
<form name="frm" action="saveImage.jsp" enctype="multipart/form-data" method="post">
<input type="file" name="uProperty" /> <br>
<input type="submit" name="goUpload" value="Upload" />
</form>
</body>
</html>

saveImage.jsp

<%@ page import="java.sql.*" %>
<%@ page import="org.apache.commons.fileupload.*"%>
<%@ page import="org.apache.commons.io.output.*"%>
<%@ page import="org.apache.commons.fileupload.servlet.*"%>
<%@ page import="org.apache.commons.fileupload.disk.*"%>
<%@ page import="java.io.*"%>
<%@ page import="java.util.*"%>
<%
 Connection conn=null;
 Class.forName("com.mysql.jdbc.Driver").newInstance();
conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/online","root", "12345");

 PreparedStatement psImageInsertDatabase=null;

 byte[] b=null;
 try{
   String sqlImageInsertDatabase="insert into upload_image (bImage) values(?)";
   psImageInsertDatabase=conn.prepareStatement(sqlImageInsertDatabase);

   DiskFileItemFactory factory = new DiskFileItemFactory();

   ServletFileUpload sfu = new ServletFileUpload(factory);
   List items = sfu.parseRequest(request);

   Iterator iter = items.iterator();

     while (iter.hasNext()) {
     FileItem item = (FileItem) iter.next();
     if (!item.isFormField()) {
          b = item.get();
       }
     }

     psImageInsertDatabase.setBytes(1,b);
     psImageInsertDatabase.executeUpdate();
    }
   catch(Exception e)
   {
    e.printStackTrace();
    response.sendRedirect("addimage.jsp");
   }

   %>

get.jsp

<%@ page import ="java.sql.*" %>
<%
 Class.forName("com.mysql.jdbc.Driver");
 Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/online","root", "12345");
Statement st = con.createStatement();

ResultSet i = st.executeQuery("select * from upload_image");
%>

 <%

 while(i.next( )){
   %>
       <img src="imageServlet?id=<%=i.getString("2")%>" />
<%  }%>

执行 get.jsp 后（执行 uploadimage.jsp 之后）我得到"Column '2' not found."请帮我在jsp页面中显示图像< / p>

Answer 1

它抛出错误导致它找到一个名为2的列，因为你已经将2放在双引号中。我觉得它应该是1而不是2（但你知道的更好）这是下面的答案

 <img src="imageServlet?id=<%=i.getString(1)%>" />//with no quotes as you can see

或

<img src="imageServlet?id=<%=i.getString("iImageID")%>" />

在jsp中显示blob图像（javax.servlet.ServletException：java.sql.SQLException：找不到列'2'。）

1 个答案: