JDBC中大文本类型的处理

Oracle中大文本数据类型
Clob 长文本类型
Blob 二进制类型

MySQL数据库
Text 长文本类型
Blob 二进制类型

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-- 测试大数据类型CREATE TABLE test(     id INT PRIMARY KEY AUTO_INCREMENT,     content LONGTEXT,     img LONGBLOB);

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Text:

public class App_text {    // 全局参数    private Connection con;    private Statement stmt;    private PreparedStatement pstmt;    private ResultSet rs;    @Test    // 1. 保存大文本数据类型   ( 写longtext)    public void testSaveText() {        String sql = "insert into test(content) values(?)";        try {            // 连接            con = JdbcUtil.getConnection();            // pstmt 对象            pstmt = con.prepareStatement(sql);            // 设置参数            // 先获取文件路径            String path = App_text.class.getResource("tips.txt").getPath();            FileReader reader = new FileReader(new File(path));            pstmt.setCharacterStream(1, reader);            // 执行sql            pstmt.executeUpdate();            // 关闭            reader.close();        } catch (Exception e) {            e.printStackTrace();        } finally {            JdbcUtil.closeAll(con, pstmt, null);        }    }    @Test    // 2. 读取大文本数据类型   ( 读longtext)    public void testGetAsText() {        String sql = "select * from  test;";        try {            // 连接            con = JdbcUtil.getConnection();            // pstmt 对象            pstmt = con.prepareStatement(sql);            // 读取            rs = pstmt.executeQuery();            if (rs.next()) {                // 获取长文本数据, 方式1:                //Reader r = rs.getCharacterStream("content");                // 获取长文本数据, 方式2:                System.out.print(rs.getString("content"));            }        } catch (Exception e) {            e.printStackTrace();        } finally {            JdbcUtil.closeAll(con, pstmt, null);        }    }}

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blob

public class App_blob {    // 全局参数    private Connection con;    private Statement stmt;    private PreparedStatement pstmt;    private ResultSet rs;    @Test    // 1. 二进制数据类型   ( 写longblob)    public void testSaveText() {        String sql = "insert into test(img) values(?)";        try {            // 连接            con = JdbcUtil.getConnection();            // pstmt 对象            pstmt = con.prepareStatement(sql);            // 获取图片流            InputStream in = App_text.class.getResourceAsStream("7.jpg");            pstmt.setBinaryStream(1, in);            // 执行保存图片            pstmt.execute();            // 关闭            in.close();        } catch (Exception e) {            e.printStackTrace();        } finally {            JdbcUtil.closeAll(con, pstmt, null);        }    }    @Test    // 2. 读取大文本数据类型   ( 读longblob)    public void testGetAsText() {        String sql = "select img from  test where id=2;";        try {            // 连接            con = JdbcUtil.getConnection();            // pstmt 对象            pstmt = con.prepareStatement(sql);            // 读取            rs = pstmt.executeQuery();            if (rs.next()) {                // 获取图片流                InputStream in = rs.getBinaryStream("img");                // 图片输出流                FileOutputStream out = new FileOutputStream(new File("c://1.jpg"));                int len = -1;                byte b[] = new byte[1024];                while ((len = in.read(b)) != -1) {                    out.write(b, 0, len);                }                // 关闭                out.close();                in.close();            }        } catch (Exception e) {            e.printStackTrace();        } finally {            JdbcUtil.closeAll(con, pstmt, null);        }    }}