jdbcbean.java

这是用JAVA做的一个BOOKSTORE的模拟程序,运行之后的用户名 和密码就靠读者的智慧了 ,从源码里可以找到

package BookStore;

import java.io.*;
import java.sql.*;
import java.util.*;
import javax.naming.*;
import javax.sql.*;


public class JDBCBean implements Serializable{

  Connection conn = null;
  Statement stmt = null;
  ResultSet rs = null;
  DataSource ds = null;

  //构造方法，初始化环境，查找数据源
  public JDBCBean()
  {
    try{
      Context ctx = null;

      // Put connection properties in to a hashtable
      Hashtable ht = new Hashtable();
      ht.put(Context.INITIAL_CONTEXT_FACTORY,
             "weblogic.jndi.WLInitialContextFactory");
      ht.put(Context.PROVIDER_URL,
             "t3://localhost:7001");

      //获取 weblogic Server JNDI的初始上下文环境
      ctx = new InitialContext(ht);

      //查找 JNDI名字为 myConnection 的数据源
      ds = (DataSource) ctx.lookup("myConnection");
    }
    catch (Exception e)
    {
      System.out.println("getConnection method is Error: " + e.getMessage());
    }
  }


//建立连接,此连接为JDBC－应用服务器连接，需要先建连接池与数据源
//且数据源的JNDI名字为myConnection
  public void getJDBCConnection(){
  try{

        //从连接池里取出一个连接
        conn = ds.getConnection();
        //建立语句对象
        stmt = conn.createStatement();

  }
  catch(Exception e){
    System.out.println("Connection is Error: " + e.getMessage());
  }
  }


//关闭连接
  public void closeConnect()
  {
    try
    {
      if (rs != null)
        rs.close(); //关闭结果集

      if (stmt != null)
        stmt.close(); //关闭语句对象

      if (conn != null)
        conn.close(); //关闭连接

    }
    catch (Exception e)
    {
      System.out.println("myConnection is Error: " + e.getMessage());
      rs = null;
      stmt = null;
      conn = null;
    }
  }

//查书的数量
  public int queryNum(String bookBH)
  {
    String query = "SELECT * from BookInfo where BookBH ="+bookBH;
    System.out.println(query);
    try
    {
      if (conn == null)
        //先连接数据库
        getJDBCConnection();

      System.out.println("connection ok");
      rs = stmt.executeQuery(query);
      System.out.println("query ok");
      int temp = 0;
      while(rs.next())
      {
      temp =  rs.getInt("BookNumber");
      }
      System.out.println("数量为"+temp);

      closeConnect();
      return temp;

    }

    catch (Exception e)
    {
         System.out.println("executeQuery error here: " + e.getMessage());
    }
    closeConnect();
    return 0;
  }

//执行查询sql语句
  public ResultSet selectBookInfo(){
  rs = null;
  String sql = "SELECT * FROM BookInfo";

  try{
    if(conn == null)
      //先连接数据库
        getJDBCConnection();

    rs = stmt.executeQuery(sql);  //执行查询sql语句

  }catch(Exception e){
     System.out.println("executeQuery error here: " + e.getMessage());
  }
  return rs;
  }

//执行更新sql语句
  public boolean executeUpdate(String bookBH,int newNum){
    boolean update = false;
    int rowCount = 0;
    newNum--;
    String sql = "UPDATE BookInfo SET BookNumber="+newNum+" WHERE BookBH="+bookBH;
    System.out.println(sql);

    try{
      if(conn == null)
        //如果没连接，先连接数据库
        getJDBCConnection();

      if(conn != null){  //有连接，则执行sql更新语句
        stmt = conn.createStatement();
        rowCount = stmt.executeUpdate(sql);
        if(rowCount != 0)

          update = true;
      }

    }catch(SQLException e){
      System.err.println("Conn.executeUpdate " + e.getMessage());
    }
    //关闭连接
    closeConnect();
    return update;
  }



}