Java+mysql本地图片上传数据库及下载示例

create table image (id int primary key auto_increment ,  name varchar(30) COMMENT '名称',  content mediumblob COMMENT '图片');

package jdbc_imagetest;import java.io.*;import java.sql.*;/** * 将本地文件的图片传到数据库的test的image表中并下载到本机桌面 */public class Test1 {  private static String url="jdbc:mysql://localhost:3306/test";  private static String user="root";  private static String password="123456";  private static Connection con;  public static void main(String[] args) throws Exception {    Class.forName("com.mysql.jdbc.Driver");    con=DriverManager.getConnection(url,user,password);    shangchuan();    xiazai();      }  //添加图片到数据库test4的file表  public static void shangchuan() throws Exception{    String sql="insert into image(name,content) values(?,?)";    PreparedStatement ptmt=con.prepareStatement(sql);    ptmt.setString(1, "美女.jpg");    InputStream is=null;    is=new FileInputStream("D://Pictures//3.jpg");    ptmt.setBinaryStream(2, is,is.available());    //方法说明：PreparedStatement.setBinaryStream(int parameterIndex, InputStream x, int length)    ptmt.execute();    System.out.println("图片添加成功！");  }  //从数据库中把图片下载至桌面  public static void xiazai() throws Exception{    String sql="select content from image where id=3";//在我这里3.jpg是第三张图片    Statement stmt=con.createStatement();    ResultSet rs=stmt.executeQuery(sql);//将查询结果给rs    if(rs.next()){      InputStream is=rs.getBinaryStream("fcontent");      //.getBinaryStream():a Java input stream that delivers the database column value as a stream of uninterpreted bytes      FileOutputStream fos=new FileOutputStream("C://Users//Desktop//美女.jpg");      byte[] buffer=new byte[1024];      int len=0;      while((len=is.read(buffer))!=-1){        fos.write(buffer,0,len);//将数据库的图片写出      }      System.out.println("下载成功！已下载至桌面，请查看");    }else{      System.out.println("图片不存在！");    }    con.close();  }}