webrowsetexample.java

此程序都是企业级 的数据库开发程序 全面揭示了JAVA对数据库的操作

//  com/wrox/rowset/WebRowSetExample.java
package com.wrox.rowset;

import java.io.*;
import java.sql.*;
import javax.sql.*;
import sun.jdbc.rowset.*;

public class WebRowSetExample {
  WebRowSet webRs;
  int recordingid;

  public static void main(String[] args) {
    WebRowSetExample wrse = new WebRowSetExample();
    try {
      boolean done = false;
      BufferedReader in = 
	new BufferedReader(new InputStreamReader(System.in));
      while (!done) {
	wrse.recordingid = 0;
	System.out.print("Enter a RecordingId (0 to exit) : ");
	String s = in.readLine();
	int result = new Integer(s).intValue();
	if (result == 0) {
	  done = true;
	} else {
	  wrse.recordingid = result;
	  wrse.populateRowSet();
	  wrse.writeXml();
	}
      }
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

  void populateRowSet()
    throws ClassNotFoundException, SQLException 
  {
    Connection connection = null;
    try {
      Class.forName("COM.cloudscape.core.JDBCDriver");
      String url = "jdbc:cloudscape:c:/wrox/database/Wrox4370.db";
      String username = "APP";
      String password = "";
      connection = DriverManager.getConnection(url, username, password);
      Statement statement = connection.createStatement();
      String sqlCount = "SELECT count(*) FROM tracks WHERE " +
	"recordingid=" + recordingid;
      ResultSet rset = statement.executeQuery(sqlCount);
      int count = 0;
      if (rset.next()) {
	count = rset.getInt(1);
      }

      webRs = null;
      if (count > 0) {
	System.out.println("Found " + count +
			   " tracks for recordingid " + recordingid);
	System.out.println("Querying database for track data...");
	String sqlQuery = "SELECT * FROM tracks WHERE " +
	  "recordingid=" + recordingid;
	webRs = new WebRowSet();
	webRs.setCommand(sqlQuery);
	webRs.execute(connection);
      }
    } finally {
      try { connection.close(); } catch (Exception ignored) {}
    }
  }

  void writeXml() throws SQLException, IOException
  {
    if (webRs == null) {
      System.out.println("No track data found for recording id");
      return;
    }
    FileWriter fw = null;
    try {
      File file = new File("recording" + recordingid + "Tracks.xml");
      fw = new FileWriter(file);
      System.out.println("Writing track data to file " + 
			 file.getAbsolutePath());
      webRs.writeXml(fw);
    } finally {
      fw.flush();
      fw.close();
    }
  }
}