jdbconnection.java

《struts 应用开发完全手册》中的源代码第一到第五章。

package com.dao;
import java.sql.*;

public class JDBConnection {
    private final String dbDriver = "net.sourceforge.jtds.jdbc.Driver"; //连接sql数据库的方法
      private final String url = "jdbc:jtds:sqlserver://localhost:1433/db_dispatch";
      private final String userName = "sa";
      private final String password = "";
      private Connection con = null;

      public JDBConnection() {
       try {
         Class.forName(dbDriver).newInstance();         //加载数据库驱动
       }
       catch (Exception ex) {
         System.out.println("数据库加载失败");
       }
     }

//创建数据库连接
      public boolean creatConnection() {
        try {
          con = DriverManager.getConnection(url, userName, password);
          con.setAutoCommit(true);

        }
        catch (SQLException e) {
          System.out.println(e.getMessage());
          System.out.println("creatConnectionError!");
        }
        return true;
      }
//对数据库的增加、修改和删除的操作
      public boolean executeUpdate(String sql) {

        if (con == null) {
          creatConnection();
        }
        try {
          Statement stmt = con.createStatement();
          int iCount = stmt.executeUpdate(sql);
          System.out.println("操作成功，所影响的记录数为" + String.valueOf(iCount));
        }
        catch (SQLException e) {
          System.out.println(e.getMessage());
          System.out.println("executeUpdaterError!");
        }
        return true;
      }
//对数据库的查询操作
      public ResultSet executeQuery(String sql) {
        ResultSet rs;
        try {
          if (con == null) {
            creatConnection();
          }
          Statement stmt = con.createStatement();
          try {
            rs = stmt.executeQuery(sql);
          }
          catch (SQLException e) {
            System.out.println(e.getMessage());
            return null;
          }
        }
        catch (SQLException e) {
          System.out.println(e.getMessage());
          System.out.println("executeQueryError!");
          return null;
        }
        return rs;
      }
//关闭数据库的操作
      public void closeConnection() {
        if (con != null) {
          try {
            con.close();
          }
          catch (SQLException e) {
            e.printStackTrace(); //To change body of catch statement use File | Settings | File Templates.
            System.out.println("Failed to close connection!");
          }
          finally {
            con = null;
          }
        }
      }

}