dbconn.java

试卷分析系统 基于struts的试卷分析系统！ 对初学框架的人很有好处哦！

/*
 * Created on 2006-3-512:38:57
 *
 * To change the template for this generated file go to
 * Window>Preferences>Java>Code Generation>Code and Comments
 */
package com.hbnu.common;
import java.sql.*;
import java.util.ArrayList;
/**
 * @author aim
 *
 * To change the template for this generated type comment go to
 * Window>Preferences>Java>Code Generation>Code and Comments
 */
/**
 * 公用数据库访问类
 */
public class DBConn
{
    
    ResultSet rs=null;
	/**数据库连接对象*/
	private Connection conn = null;
	/**数据库执行对象*/
	private Statement statement =null;
	/**记录数据库列数*/
	private int columNum = 0;
	/**记录数据库中数据的行数*/
	private int velNum = 0;
	/**驱动程序地址、用户、密码*/ 
    String sConnStr="jdbc:mysql://127.0.0.1:3306/sjfx?user=root&password=1234&useUnicode=true&characterEncoding=GB2312"; 
/**
 * 连接数据库函数
 * @throws SQLException
 * @throws ClassNotFoundException
 * @throws IllegalAccessException
 * @throws InstantiationException
 */
public void start() throws SQLException, InstantiationException, IllegalAccessException, ClassNotFoundException{
	Class.forName("org.gjt.mm.mysql.Driver").newInstance();
	conn= DriverManager.getConnection(sConnStr);
	statement=conn.createStatement();
}
/**
 * 删除对象函数
 * @param sql       SQL执行语句
 * @throws Exception
 */
public int execDelete(String sql) throws Exception {	
	return execInsert(sql);
	}
/**
 * 修改对象函数
 * @param sql       SQL执行语句
 * @throws Exception
 */	
public int execUpdate(String sql) throws SQLException, Exception {
	return execInsert(sql);
}

/**
 * 插入数据函数
 * @param sql       SQL执行语句
 * @throws Exception
 */	
public int execInsert(String sql) throws SQLException, Exception {
	
	PreparedStatement statement = null;
	int rstCnt = 0;
	
	try {
		statement =conn.prepareStatement(sql);
		/* SQL返回聚集 */
		rstCnt = statement.executeUpdate();
		
	} catch (SQLException e) {
		throw e;
		
	} finally {
		/* 判断 */
		if (statement != null) {
			statement.close();
			statement = null;
		}
	}
	
	return rstCnt;
}

/**
 * 关闭数据库连接
 * @throws Exception
 */   
public void execClose()throws Exception{
	statement.close();
	conn.close();	
    }
/**
 * 返回数据记录的列数
 * @return
 */
public int getColumNum() {
	return this.columNum;
	}
/**
 * 返回数据记录的行数
 * @return
 */
public int getvelNum() {
	return this.velNum;
	}
/**
 * 数据查询函数
 * @param sql       SQL执行语句
 * @return          返回数据结果
 * @throws Exception
 */	    
public ArrayList execSelect(String sql) throws Exception {
	ResultSet rs=statement.executeQuery(sql); 
	ArrayList arrayList = new ArrayList();
	try {
		  if ( rs != null ) {
			    /*创建一个元数据，描述数据库信息或数据库的一部分数据*/
			    ResultSetMetaData rsmd = rs.getMetaData();
				/*获得数据记录列数*/
			    columNum = rsmd.getColumnCount();
			    /*建立字符串数组，每个数组存储一条记录*/
				String[] strRow = new String[columNum];	
				velNum = 0;
				/*循环访问数据结果*/				
				while(rs.next()) {
					/*把一条记录存储到一个数组中*/
					for (int i=1; i<=columNum; i++) {
						strRow[i-1] = rs.getString(i);
						}
					/*把字符串数组加到arraylist对象中*/
					arrayList.add(strRow.clone());
					velNum++;
						}						
			    }
		  else
			  velNum = 0;
		}
	catch (SQLException e) {
		throw e;			
		} 
	finally {			
		if (rs != null) {
			/*关闭数据结果集*/
		     rs.close();
		     rs = null;
		     }
		}		
	return arrayList;
}
}