数据库上传下载图片

//建立数据连接
Connection cn=null;
try {
String url="jdbc:jtds:sqlserver://192.168.1.56:1433/test";
Class.forName("net.sourceforge.jtds.jdbc.Driver");
cn=DriverManager.getConnection(url,"sa","sa");
} catch (Exception e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}


//保存图片到数据库；
try
{
FileInputStream file=new FileInputStream("f:/line3.jpg");
PreparedStatement st=cn.prepareStatement("insert into img values(?)");

st.setBinaryStream(1,file,file.available());//得到文件大小
st.execute();
System.out.println(file.available());
System.out.println("成功");
}
catch(Exception e)
{
e.printStackTrace();
}
//读取图片从数据库
try
{
PreparedStatement st=cn.prepareStatement("select * from img ");
ResultSet rs=st.executeQuery();
byte b[]=new byte[100000];
while(rs.next())
{
InputStream in=rs.getBinaryStream(1);
in.read(b);
File file=new File("F:/test.jpg"); //建立一个文件路径
FileOutputStream write=new FileOutputStream(file);//把文件输出到此路径
write.write(b);
write.close();
}
}catch(Exception e){
e.printStackTrace();
}

}