blob类型字段[通俗易懂]

 @Test
public void testInsert() { 

Connection conn=null;
PreparedStatement ps=null;
try { 

//1、连接数据库
conn = JDBCUtils.getConnection();
//2、预编译sql
String sql = "insert into customers(name,email,birth,photo) values(?,?,?,?)";
//3、获得PreparedStatement对象
ps = conn.prepareStatement(sql);
ps.setObject(1, "刘备");
ps.setObject(2, "liu@qq.com");
ps.setObject(3, "1992-09-08");
FileInputStream is = new FileInputStream(new File("推广004.png"));
ps.setBlob(4, is);
//提交
ps.execute();
} catch (Exception e) { 

e.printStackTrace();
} finally { 

JDBCUtils.closeResouce(conn, ps);
}
}

@Test
public void testQuery(){ 

Connection conn=null;
PreparedStatement ps=null;
ResultSet rs=null;
InputStream is=null;
FileOutputStream fos=null;
try { 

//1、连接数据库
conn = JDBCUtils.getConnection();
//2、预编译sql
String sql = "select id,name,email,birth,photo from customers where id = ?";
ps = conn.prepareStatement(sql);
ps.setInt(1, 27);
//3、提交数据
rs = ps.executeQuery();
if(rs.next()){ 

int id=rs.getInt("id");
String name=rs.getString("name");
String email=rs.getString("email");
Date birth = rs.getDate("birth");
Customer cus = new Customer(id,name,email,birth);
System.out.println(cus);
//将Blob类型以文件的方式保存在本地
Blob photo = rs.getBlob("photo");
is = photo.getBinaryStream();
fos = new FileOutputStream("01.jpg");
byte[] buffer = new byte[1024];
int len;
while ((len=is.read(buffer))!=-1){ 

fos.write(buffer,0,len);
}
}
} catch (Exception e) { 

e.printStackTrace();
}finally { 

try { 

if(is != null)
is.close();
} catch (IOException e) { 

e.printStackTrace();
}
try { 

if(fos != null)
fos.close();
} catch (IOException e) { 

e.printStackTrace();
}
JDBCUtils.closeResource(conn,ps,rs);
}
}