database.java

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");
  }

  /**
   * 编码转换
   */

  public String toSql(String newString) {
    try {
      String sqlString = new String(newString.getBytes("ISO-8859-1"), "GBK");
      return sqlString;
    }
    catch (Exception e) {}
    return "null";
  }

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

  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,ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
  }

  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);

    }

  }

}