//获取连接
Connection conn = JDBCUtils.getConnection();
String sql = "insert into customers(name,email,birth,photo)values(?,?,?,?)";
PreparedStatement ps = conn.prepareStatement(sql);
//填充占位符
ps.setString(1, "韩立人");
ps.setString(2, "hlr@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)

查询BOLB类型数据

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 = photo.getBinaryStream();//从查询出来的Blob对象中获取二进制流
    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();
}

二、批量插入

批量执行SQL语句

当需要成批插入或者更新记录时，可以采用java的批量更新机制，这一机制允许多条语句一次性提交给数据库批量处理。通常情况下比单独提交处理更有效率

JDBC的批量处理语句包括下面三个方法

1、addBatch(String)：添加需要批量处理的SQL语句或是参数
2、executeBatch()：执行批量处理语句
3、clearBatch()：清空缓存的数据

两种批量执行SQL语句的情况：

多条SQL语句的批量处理
一个SQL语句的批量传参

高效的批量插入：

方式一：使用Statement

Connection conn = JDBCUtils.getConnection();
Statement st = conn.createStatement();
for(int i = 1;i <= 20000;i++){
    String sql = "insert into goods(name) values('name_' + "+ i +")";
    st.executeUpdate(sql);
}

方式二：使用PreparedStatement(比Statement高效)

long start = System.currentTimeMillis();
Connection conn = JDBCUtils.getConnection();
String sql = "insert into goods(name)values(?)";
PreparedStatement ps = conn.prepareStatement(sql);
for(int i = 1;i <= 20000;i++){
    ps.setString(1, "name_" + i);
    ps.executeUpdate();
}
long end = System.currentTimeMillis();
System.out.println("花费的时间为：" + (end - start));//82340
JDBCUtils.closeResource(conn, ps);

方式三：使用批量处理语句对方式二优化

public void testInsert1() throws Exception{
        long start = System.currentTimeMillis();
        Connection conn = JDBCUtils.getConnection();
        String sql = "insert into goods(name)values(?)";
        PreparedStatement ps = conn.prepareStatement(sql);
        for(int i = 1;i <= 1000000;i++){
            ps.setString(1, "name_" + i);
            //1.“攒”sql
            ps.addBatch();
            if(i % 500 == 0){
                //2.执行
                ps.executeBatch();
                //3.清空
                ps.clearBatch();
            }
        }
        long end = System.currentTimeMillis();
        System.out.println("花费的时间为：" + (end - start));//20000条：625
        //1000000条:14733
        JDBCUtils.closeResource(conn, ps);
}

方式四：使用Connection的setAutoCommit()方法对方式三优化

public void testInsert2() throws Exception{
    long start = System.currentTimeMillis();
    Connection conn = JDBCUtils.getConnection();
    //1.设置为不自动提交数据
    conn.setAutoCommit(false);
    String sql = "insert into goods(name)values(?)";
    PreparedStatement ps = conn.prepareStatement(sql);
    for(int i = 1;i <= 1000000;i++){
        ps.setString(1, "name_" + i);
        //1.“攒”sql
        ps.addBatch();
        if(i % 500 == 0){
            //2.执行
            ps.executeBatch();
            //3.清空
            ps.clearBatch();
        }
    }
    //2.手动提交数据
    conn.commit();
    long end = System.currentTimeMillis();
    System.out.println("花费的时间为：" + (end - start));//1000000条:4978
    JDBCUtils.closeResource(conn, ps);
}