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How do I query and insert CLOBs data from database?

程序员文章站 2024-03-04 12:31:05
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Only for reference.

 

import java.io.File;
import java.io.FileWriter;
import java.io.Reader;
import java.sql.*;

public class TestOperClob {
private static String url = "jdbc:oracle:thin:@localhost:1521:orcl";
    private static String username = "test";
    private static String password = "test";

    public void queryClob(){
      Connection conn = null;
        try {
            conn = getConnection();
            String sql = "SELECT name, description, data FROM documents ";
            PreparedStatement stmt = conn.prepareStatement(sql);
            ResultSet resultSet = stmt.executeQuery();
            while (resultSet.next()) {
                String name = resultSet.getString(1);
                System.out.println("Name        = " + name);
                String description = resultSet.getString(2);
                System.out.println("Description = " + description);

                File data = new File("C:\\The Appfuce Primer.txt");

                // Get the character stream of our CLOB data
                Reader reader = resultSet.getCharacterStream(3);
                FileWriter writer = new FileWriter(data);
                char[] buffer = new char[1];
                while (reader.read(buffer) > 0) {
                    writer.write(buffer);
                }
                writer.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            closeConnection(conn);
        }
    }

    public void insertClob(){
      try{
          conn = getConnection();
          conn.setAutoCommit(false);
          String sql = "INSERT INTO documents (name, description, data) VALUES (?, ?, ?)";
          PreparedStatement stmt = conn.prepareStatement(sql);
          stmt.setString(1, "The AppFuse Primer.txt");
          stmt.setString(2, "The AppFuse Primer");

          File data = new File("C:\\The AppFuse Primer.txt");
          reader = new FileReader(data);
          stmt.setCharacterStream(3, reader, (int) data.length());
          stmt.execute();
          conn.commit();
      } catch (SQLException e) {
          e.printStackTrace();
      } finally {
          if (reader != null) {
              reader.close();
          }
          closeConnection(conn);
      }
    }

     private static Connection getConnection() throws Exception {  
        Connection connection = null;  
        Class.forName("com.mysql.jdbc.Driver");  
        connection = DriverManager.getConnection("jdbc:mysql://localhost/bookstore", "root", "");  
        return connection;  
    }  
      
    private static void closeConnection(Connection connection) throws SQLException {  
        if (connection != null && !connection.isClosed()) {           
            connection.close();  
        }  
    }
    public static void main(String[] args) throws Exception {
        queryClob();
        insertClob();
    }
}