資料庫中使用Blob處理位元據__資料庫

長文本（Clob）和二進位檔案（Blob）的處理痛點其實不再JDBC上，而是在輸入輸出上。

package cn.itcast.jdbc;import java.io.BufferedInputStream;import java.io.BufferedOutputStream;import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.OutputStream;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;//blob最大64Kpublic class BlobTest {    public static void main(String[] args) throws SQLException, IOException {//      create();        read();    }    // 跟clob差不多，只是修改了Reader為InputStream，並setBinaryStream()設定二進位流    static void create() throws SQLException, IOException {        Connection conn = null;        PreparedStatement ps = null;        ResultSet rs = null;        try {            conn = JdbcUtils.getConnection();            String sql = "insert into blob_test(big_bit)values(?)";            ps = conn.prepareStatement(sql);            File file = new File("mudan.jpg");            InputStream in = new BufferedInputStream(new FileInputStream(file));            ps.setBinaryStream(1, in, (int) file.length()); // 位元組流            int i = ps.executeUpdate();            in.close();            System.out.println("i=" + i);        } finally {            JdbcUtils.free(rs, ps, conn);        }    }    static void read() throws SQLException, IOException {        Connection conn = null;        Statement st = null;        ResultSet rs = null;        try {            conn = JdbcUtils.getConnection();             st = conn.createStatement();            rs = st.executeQuery("select big_bit from blob_test");            while (rs.next()) {//              方法1 //              Blob blob = rs.getBlob("1");    //              InputStream in = blob.getBinaryStream();//              方法2，這個方法更好                InputStream in=rs.getBinaryStream(1);                   File file = new File("COPY.jpg");                OutputStream out = new BufferedOutputStream(new FileOutputStream(file)) ;                byte[] buff = new byte[1024]; // 緩衝區                for (int i = 0; (i = in.read(buff)) > 0;)                    out.write(buff, 0, i);                out.close();                in.close();            }        } finally {            JdbcUtils.free(rs, st, conn);        }    }}