2018.7.30 Oracle的Bolog数据库类型读取和存储

package com.lanqiao.shopping.test;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import com.lanqiao.shopping.utils.DBHelper;

public class Test {
    static PreparedStatement pstmt = null;
    static ResultSet rs = null;
    /*
     * 创建图片的表myPicture
     *     create  table myPicture(id number(4) primary key,img blob);
     */
    
    //将图片写进数据库
    public static void writeImgToBolb(){
        Connection conn = DBHelper.getConn();
        String sql = "insert into myPicture(id,img) values(?,?)";
        
        try {
            pstmt = conn.prepareStatement(sql);
            pstmt.setInt(1,3);//id
            
            //将图片转为输入流
            File file = new File("D:EclipseImagesSaveone.jpg");
            InputStream in = new FileInputStream(file);
            
            /*
            String a = "sss";
            System.out.println(a.length());//字符串是length方法
            int[] i = new int[5];//数组是length属性
            System.out.println(i.length);*/
            
            
            //将输入流写入到myPicture表
            pstmt.setBinaryStream(2,in,(int)file.length());
            
            int result = pstmt.executeUpdate();
            System.out.println("111");
            if(result>0){
                System.out.println("图片写入成功");
            }else{
                System.out.println("图片写入失败");
            }
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally {
            DBHelper.closeConn(null,pstmt,conn);
        }
        
    }
    
    //从数据库读取图片
    public static void readImgToBlob(){
        Connection conn = DBHelper.getConn();
        String sql = "select * from myPicture where id=?";
        try {
            pstmt = conn.prepareStatement(sql);
            pstmt.setInt(1,1);//id =1
            rs = pstmt.executeQuery();
            if(rs.next()){
                //将图片从数据库中读取出来，类型为InputStream
                InputStream imgIn = rs.getBinaryStream("img");
                
                //通过IO流，将图片写到项目中(硬盘)
                InputStream in = new BufferedInputStream(imgIn);
                
                //将图片的输出路径设置为src(相对路径),图片名为myPic.png
                OutputStream imgOut = new FileOutputStream("D:EclipseImagesSavemyPic.jpg");
                OutputStream out = new BufferedOutputStream(imgOut);
                
                int len = -1;
                while((len=in.read())!=-1){
                    out.write(len);
                }
                
                imgOut.close();
                out.close();
                imgIn.close();
                in.close();
                System.out.println("照片读取成功");
                
            }
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally {
            DBHelper.closeConn(rs,conn);
        }
        
    }
    
    public static void main(String[] args) {
        //writeImgToBolb();
        readImgToBlob();
    }
}

（编辑：李大同）

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