database.java~3~

图书管理系统,B/S,C/S都有,附有源代码

package database;

import java.sql.*;
import database.*;

/**
 * <p>Title: library</p>
 * <p>Description: library</p>
 * <p>Copyright: Copyright (c) 2007</p>
 * <p>Company: </p>
 * @author nino
 * @version 0.1
 */

public class DataBase {
  private Connection conn = null;
  private Statement stmt = null;
  private PreparedStatement prepstmt = null;
  private DBConnectionManager dcm=null;

void init() {
  dcm = DBConnectionManager.getInstance();
          conn = dcm.getConnection("library");
}

  /**
   * 构造数据库的连接和访问类
   */
  public DataBase() throws Exception {
  init();
          stmt = conn.createStatement();
  }

public DataBase(int resultSetType, int resultSetConcurrency)
      throws Exception {
  init();
  stmt = conn.createStatement(resultSetType, resultSetConcurrency);
}

/**
* 构造数据库的连接和访问类
* 预编译SQL语句
* @param sql SQL语句
*/
  public DataBase(String sql) throws Exception {
  init();
          this.prepareStatement(sql);
  }

  public DataBase(String sql, int resultSetType, int resultSetConcurrency)
      throws Exception {
  init();
          this.prepareStatement(sql, resultSetType, resultSetConcurrency);
  }

  /**
   * 返回连接
   * @return Connection 连接
   */
  public Connection getConnection() {
          return conn;
  }

  /**
   * PreparedStatement
   * @return sql 预设SQL语句
   */
  public void prepareStatement(String sql) throws SQLException {
          prepstmt = conn.prepareStatement(sql);
  }

  public void prepareStatement(String sql, int resultSetType, int resultSetConcurrency)
      throws SQLException {
          prepstmt = conn.prepareStatement(sql, resultSetType, resultSetConcurrency);
  }

  /**
   * 设置对应值
*
   * @param index 参数索引
   * @param value 对应值
   */
  public void setString(int index,String value) throws SQLException {
          prepstmt.setString(index, value);
  }
  public void setInt(int index,int value) throws SQLException {
          prepstmt.setInt(index,value);
  }
  public void setBoolean(int index,boolean value) throws SQLException {
          prepstmt.setBoolean(index,value);
  }
  public void setDate(int index,Date value) throws SQLException {
          prepstmt.setDate(index,value);
  }
  public void setLong(int index,long value) throws SQLException {
          prepstmt.setLong(index,value);
  }
  public void setFloat(int index,float value) throws SQLException {
          prepstmt.setFloat(index,value);
  }
  public void setBytes(int index,byte[] value) throws SQLException{
          prepstmt.setBytes(index,value);
  }



public void clearParameters()
  throws SQLException
{
  prepstmt.clearParameters();
  prepstmt=null;
}
  /**
   * 返回预设状态
   */
  public PreparedStatement getPreparedStatement() {
          return prepstmt;
  }
  /**
   * 返回状态
   * @return Statement 状态
   */
  public Statement getStatement() {
          return stmt;
  }
  /**
   * 执行SQL语句返回字段集
   * @param sql SQL语句
   * @return ResultSet 字段集
   */
  public ResultSet executeQuery(String sql) throws SQLException {
          if (stmt != null) {
                  return stmt.executeQuery(sql);
          }
          else return null;
  }

  public ResultSet executeQuery() throws SQLException {
          if (prepstmt != null) {
                  return prepstmt.executeQuery();
          }
          else return null;
  }

  /**
   * 执行SQL语句
   * @param sql SQL语句
   */
  public void executeUpdate(String sql) throws SQLException {
          if (stmt != null)
                  stmt.executeUpdate(sql);
  }
  public void executeUpdate() throws SQLException {
          if (prepstmt != null)
                  prepstmt.executeUpdate();
  }
  /**
   * 关闭连接
   */
  public void close() throws Exception {
          if (stmt != null)  {
                  stmt.close();
                  stmt = null;
          }
          if (prepstmt != null) {
                  prepstmt.close();
                  prepstmt = null;
          }
          if (conn!=null)
          {

                  dcm.freeConnection("mysql",conn);

          }

  }

}