jdbc 如何读写 blob 类型的数据？

向数据表中插入大数据类型

获取连接
Connection conn = JDBCUtils.getConnection();

String sql = "insert into customers(name,email,birth,photo)values(?,?,?,?)";
PreparedStatement ps = conn.prepareStatement(sql);
//java项目www fhadmin org
// 填充占位符
ps.setString(1, "张强");
ps.setString(2, "123@126.com");
ps.setDate(3, new Date(new java.util.Date().getTime()));
// 操作Blob类型的变量
FileInputStream fis = new FileInputStream("xhq.png");
ps.setBlob(4, fis);
//执行
ps.execute();

fis.close();
JDBCUtils.closeResource(conn, ps);

3 修改数据表中的Blob类型字段

Connection conn = JDBCUtils.getConnection();
String sql = "update customers set photo = ? where id = ?";
PreparedStatement ps = conn.prepareStatement(sql);
//java项目www fhadmin org
// 填充占位符
// 操作Blob类型的游戏代理变量
FileInputStream fis = new FileInputStream("coffee.png");
ps.setBlob(1, fis);
ps.setInt(2, 25);
ps.execute();
fis.close();
JDBCUtils.closeResource(conn, ps);

文章图片来源：游戏代理

4 从数据表中读取大数据类型

//java项目www fhadmin org
String sql = "SELECT id, name, email, birth, photo FROM customer WHERE id = ?";
conn = getConnection();
ps = conn.prepareStatement(sql);
ps.setInt(1, 8);
rs = ps.executeQuery();
if(rs.next()){
Integer id = rs.getInt(1);
String name = rs.getString(2);
String email = rs.getString(3);
Date birth = rs.getDate(4);
Customer cust = new Customer(id, name, email, birth);
System.out.println(cust);
//读取Blob类型的字段
Blob photo = rs.getBlob(5);
InputStream is = phohttp://www.walajiao.comto.getBinaryStream();
OutputStream os = new FileOutputStream("c.jpg");
byte [] buffer = new byte[1024];
int len = 0;
while((len = is.read(buffer)) != -1){
os.write(buffer, 0, len);
}
JDBCUtils.closeResource(conn, ps, rs);

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

if(os != null){
os.close();
}