保存圖片、文本到數據表中去

Pst對象保存大對象： BLOB - Binaray Larg Object - > 大的二進制類型 > 4G CLOB - Character larg Object - > 大的字符類型 - > 4G

1：保存一個圖片到數據表中去 – Blob create table users( name varchar(30), img blob );

@Test
public void testBlob() throws Exception {
	Connection con = ConnUtils.getCon();
	String sql = "insert into users values(?,?)";
	PreparedStatement pst = con.prepareStatement(sql);
	pst.setString(1, "Jerry");
	pst.setBinaryStream(2, new FileInputStream("D:/相片/SAM_1720.JPG"));
	pst.execute();
	pst.close();
	con.close();
}


/**
 * 查詢出圖片，保存到一個指定的目錄下
 */
@Test
public void testQueryBlob() throws Exception {
	Statement st = con.createStatement();
	// 在公司裏面開發，禁止使用 *
	ResultSet rs = st.executeQuery("select name,img from users where name='Jerry'");
	rs.next();
	//獲取字節流
	InputStream in = rs.getBinaryStream("img");
	Files.copy(in, new File("d:/a/a.jpg").toPath(), StandardCopyOption.REPLACE_EXISTING);
	
	//如下是獲取Blob對象
	Blob blob=  rs.getBlob("img");
	in = blob.getBinaryStream();
	rs.close();
	st.close();
}

2:保存大的文本到表中去Clob

create table notes( id int, text clob );

/**
 * 讀取大的文本類型
 */
@Test
public void testReadCLOB() throws Exception{
	String sql = "select * from notes";
	PreparedStatement pst = 
			con.prepareStatement(sql);
	ResultSet rs = pst.executeQuery();
	if(rs.next()){
		InputStream in =  rs.getAsciiStream("text");
		byte[] bs = new byte[1024];
		int len =0;
		while((len=in.read(bs))!=-1){
			String str = new String(bs,0,len);
			System.err.print(str);
		}
		in.close();
	}
	pst.close();
}