Question

所以我尝试将blob图像保存到数据库中，并在点击“查看”href后显示它。但我不知道为什么这张照片无法看到。它保存在mysql数据库中......

retrieve_image.jsp：

     <%@ page import="java.sql.*,model.Upload,java.io.*,java.util.*" %> 
        <HTML>
         <table border="1">
         <tr><th>ID</th><th>Image</th></tr>
           <%
          try{      
            Class.forName("com.mysql.jdbc.Driver").newInstance();
            Connection con=DriverManager.getConnection("jdbc:mysql://localhost/backup","root","mysql");
            Statement stmt=con.createStatement();
            String strQuery = "select * from contacts";
            ResultSet rs = stmt.executeQuery(strQuery);
            while(rs.next()){
               %>
              <tr>
              <td><%=rs.getInt("contact_id")%></td>
              <td>
                <img src="RetrieveImages.java?id=<%=rs.getInt(1)%>" width="100" height="100">

        </a></td>
              </tr>
              <%
            }
            rs.close();
            con.close();
            stmt.close();
          }
          catch(Exception e)
          {
            e.getMessage();
          }
          %>
         </table>
        </HTML>

RetrieveImages是一个servlet，其请求调度程序转到...

<%@page import="java.sql.Blob"%>
<%@page import="java.io.OutputStream"%>
<%@page import="java.sql.ResultSet"%>
<%@page import="java.sql.PreparedStatement"%>
<%@page import="java.sql.DriverManager"%>
<%@page import="java.sql.Connection"%>
<%@ page import="model.Upload" %>

<%
String contact_id = request.getParameter("contact_id");
    String dbURL = "jdbc:mysql://localhost/backup";
    String dbUser = "root";
    String dbPass = "mysql";

    Connection con = null;

    try{
        Class.forName("com.mysql.jdbc.Driver");
        con = DriverManager.getConnection(dbURL, dbUser, dbPass);

        PreparedStatement ps = con.prepareStatement("select * from contacts where contact_id=?");
        ps.setString(1, contact_id);

        ResultSet rs = ps.executeQuery();

        if(rs.next()){
            Blob blob = rs.getBlob("photo");
            byte byteArray[] = blob.getBytes(1, (int)blob.length());

            response.setContentType("image");
            OutputStream os = response.getOutputStream();
            os.write(byteArray);
            os.flush();
            os.close();
        }

    }catch(Exception ex){
        ex.printStackTrace();
    }finally{
        if(con != null){
            try{
                con.close();
            }catch(Exception e){
                e.printStackTrace();
            }
        }
    }
 %>

在我的java bean中，我将contact_id和照片作为归属

保存到数据库中的图像未显示

0 个答案: