e256. getting blob data from a database table.txt

来自「这里面包含了一百多个JAVA源文件」· 文本 代码 · 共 26 行

A BLOB is a reference to data in a database. This example demonstrates how to retrieves bytes from a BLOB. 
    try {
        Statement stmt = connection.createStatement();
        ResultSet rs = stmt.executeQuery("SELECT col_blob FROM mysql_all_table");
    
        if (rs.next()) {
            // Get the BLOB from the result set
            Blob blob = rs.getBlob("col_blob");
    
            // Get the number bytes in the BLOB
            long blobLength = blob.length();
    
            // Get bytes from the BLOB in a byte array
            int pos = 1;   // position is 1-based
            int len = 10;
            byte[] bytes = blob.getBytes(pos, len);
    
            // Get bytes from the BLOB using a stream
            InputStream is = blob.getBinaryStream();
            int b = is.read();
        }
    } catch (IOException e) {
    } catch (SQLException e) {
    }