近来发现有不少人对图片(Blob)关注发贴收集图片上传下载显示

Question

import java.io.Writer;
import java.io.OutputStream;
import java.io.InputStream;
import java.io.FileOutputStream;
import oracle.sql.BLOB;
import oracle.jdbc.OracleResultSet;import java.sql.Connection;
import java.io.IOException;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;import org.apache.struts.action.ActionForm;
public class DownloadBean extends BaseBean{    private String strSELECT = "SELECT INFILE_DATA FROM BILL_INFILE_TBL" ;
    
public BLOB Download()
            throws Exception
     {
        InputStream in = null;
        OutputStream out = null;
        BLOB blob = null;
        PreparedStatement  pstmt = null;
        ResultSet rs = null;
        Connection conn = null;
        try{
            conn = getDataSource().getConnection();
            pstmt = conn.prepareStatement(strSELECT);            rs = pstmt.executeQuery();            if (rs.next()) {
                blob = (BLOB)rs.getBlob("INFILE_DATA");
                
                in = blob.getBinaryStream();
                out = new FileOutputStream("c:\\xxx.jpg");
                int BuffSize = blob.getBufferSize();
                byte[] buffer = new byte[BuffSize];
                int bytesRead = 0;
                while ((bytesRead = in.read(buffer)) != -1) {
                    out.write(buffer, 0, bytesRead);
                }
                buffer = null;
                
            }
            pstmt.clearParameters();        }catch(SQLException sqle) {
            sqle.printStackTrace();
            throw sqle;
        }catch(Exception e) {
            e.printStackTrace();
            throw e;
        }finally {
            try{
                
                in.close();
                out.close();
                in = null;
                out = null;
                blob = null;
        
            }catch(Exception e) {throw e;}            if (rs != null) {
                try{
                    rs.close();
                }catch(Exception e){throw e;}
            }            if (pstmt != null) {
                try{
                    pstmt.close();
                }catch(Exception e) {throw e;}
            }            return blob;
        }    }
}

Answer 1

import javax.sql.DataSource;
import oracle.jdbc.driver.*;
import org.apache.struts.upload.FormFile;
import java.io.*;
import java.sql.*;
import java.sql.SQLException;public class UploadBean extends BaseBean {    public static final String INFILE_DATA = "INFILE_DATA";    private String strSELECT = "SELECT INFILE_DATA FROM BILL_INFILE_TBL " ;    private String strInsertSQL = "INSERT INTO BILL_INFILE_TBL ( " +
                                  "        INFILE_DATA,          " +    
                                  "        )                " +    
                                  "  VALUES(                     " +
                                  "         EMPTY_BLOB(),    " +    
                                  "        )         ";         public void Upload(FormFile file
                       )throws Exception    {
        DataSource ds = getDataSource();        Connection con = null;
        PreparedStatement stmt =null;        try{
            con = ds.getConnection();            stmt= con.prepareStatement(strInsertSQL);            stmt.executeUpdate();
            stmt.close();            stmt=con.prepareStatement(strSELECT);            ResultSet rs = stmt.executeQuery();
            while (rs.next()) {
                    oracle.sql.BLOB blob = (oracle.sql.BLOB)rs.getBlob("INFILE_DATA");
                    BufferedOutputStream out = new BufferedOutputStream(blob.getBinaryOutputStream());
                    BufferedInputStream in = new BufferedInputStream(file.getInputStream());                    int c;
                    while ((c=in.read())!=-1) {
                        out.write(c);
                    }
                    in.close();                    out.close();             }            stmt.close();
            con.commit();        }catch(Exception e) {
            e.printStackTrace();            try{
                con.rollback();
            }catch(Exception e1) {throw e1;}            throw e;
        }finally {
            try{
                stmt.close();
            }catch(Exception e) {
                throw e;
            }            try{
                con.close();
            }catch(Exception e) {
                throw e;
            }
        }
    }
}

Answer 2

谢谢 sagittarius1979(射手爱狮子)
狮子 爱  天秤
哈哈哈哈哈

Answer 3

sagittarius1979(射手爱狮子)的不错
支持！

Answer 4

太好了。
  DESL (奇多多 o_O (★★★★))  
说做就做，是个好版主，
大力支持！！！

Answer 5

编译出错，
package not existsoracle.sql.BLOB;
org.apache.struts.action.ActionForm;
从那找啊

Answer 6

oracle.sql.BLOB
装oracle的驱动即可org.apache.struts.action.ActionForm
这个，你用不到，删掉吧

Answer 7

我来发布一个从服务器某目录下下载文件的例子
import java.io.IOException;
import javax.servlet.ServletException;import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.RequestDispatcher;
import java.io.File;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;public class download extends HttpServlet { private static final String CONTENT_TYPE = "text/html; charset=GBK";   //Initialize global variables
   public void init() throws ServletException {
   }
   //Process the HTTP Get request
   public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//HttpServletRequestWrapper httpReqWrapper = (HttpServletRequestWrapper) request;
//HttpServletRequest httpRequest =(HttpServletRequest)httpReqWrapper.getRequest();
try {
       downloadArtifact(request, response);
     }catch (Exception x) {
       x.printStackTrace();
       RequestDispatcher dispatcher = this.getServletContext().
           getRequestDispatcher("/common/ShowError.jsp");
      
       dispatcher.forward(request, response);
       }
    }
    
   public void downloadArtifact(HttpServletRequest request, HttpServletResponse response) throws Exception {
     Exception ex=null;
     String fileId = (String)request.getParameter("ID");
     String realFile = null;
     String realFileName = "";
     File uploadDir = new File("D:\\upload");
     if (uploadDir.isDirectory()) {
     File[] files = uploadDir.listFiles();
     for (int j = 0; j < files.length; j++) {
     File tempFile = files[j];
     if ((tempFile.getName().indexOf(fileId)) >= 0){
     //System.err.println("get The file" + tempFile.getName());
     realFile = tempFile.getName();
     break;
     }
     }
     }
     int seperatePos = realFile.lastIndexOf(".");
     String fileAppendix = realFile.substring(seperatePos+1);
     String tempFileName = realFile.substring(0,seperatePos);
     int idIndex = tempFileName.lastIndexOf(fileId);
     realFileName = tempFileName.substring(0,idIndex) + "." + fileAppendix;
    
File file = new File("D:\\upload", realFile);
if(!file.exists()) throw new Exception("Sorry, File Not Found");
     int length=(new Long(file.length())).intValue();
     response.setContentType("application/octet-stream; charset=UTF-8");
     response.setHeader("Content-disposition", "attachment; filename=\""+realFileName+"\"");
     //response.setHeader("Content-disposition", "attachment; filename=\""+file.getName()+"\"");
     //System.err.println("******" + realFileName);
     int bufferSize=1024;
BufferedOutputStream output = null;
     BufferedInputStream input = null;
     output = new BufferedOutputStream(response.getOutputStream());
     input = new BufferedInputStream(new FileInputStream(file));
     try {
       int once = 0;
       int total = 0;
      byte[] buffer = new byte[bufferSize];
       do {
         once = input.read(buffer);
         total += once;
         if (once >= 0)
           output.write(buffer, 0, bufferSize);
       }
       while ( (total < length) && (once >= 0));
       response.flushBuffer();
     }
     catch (Exception e) {
       ex = e;
     } // maybe user cancelled download
     finally {
       if (input != null) input.close();
       if(output!=null) output.close();       if(null!=ex) throw ex;
     }
    }   //Process the HTTP Post request
   public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
     doGet(request, response);
   }
}