mysql.java

mail sent and revesive system jsp+mysql

package fengyun.Fastmail.beans;

import java.sql.*;
/**
 * 处理数据库的连接和访问
 * @author sanware
 * @version 1.01
 */
public class Mysql {

	private Connection conn = null;
	private Statement stmt = null;
	private PreparedStatement prepstmt = null;
	
	private static BeansConstants CONST = BeansConstants.getInstance();

	/**
	 * 构造数据库的连接和访问类
	 */
	public Mysql() throws Exception {
		Class.forName(CONST.dbdriver);
		conn = DriverManager.getConnection(CONST.dburl);
		stmt = conn.createStatement();
	}
	public Mysql(String sql) throws Exception {
		Class.forName(CONST.dbdriver);
		conn = DriverManager.getConnection(CONST.dburl);		
		this.prepareStatement(sql);
	}
	
	/**
	 * 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);
	}
	/**
	 * 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 clearParameters()
        throws SQLException
    {
        prepstmt.clearParameters();
    }
	/**
	 * 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;
		}
		conn.close();
		conn = null;
	}
}