连接数据库的类

王朝java/jsp·作者佚名  2006-01-08
窄屏简体版  字體: |||超大  

这是我在网上找到的 CODE 基础上加以修改后自己用来连接数据库的类。

分为三个部分:参数设置,数据库连接,后面还附有应用例子。

如果不能直接应用请与我联系: fajaven@vip.sina.com

/*************************

* 连接数据库的参数设置

*************************/

package net.asales.mysql;

public class BeansConstants {

public static String dbdriver;

public static String dburl;

private String database = "asales";

private String usr = "root";

private String passwd = "";

private BeansConstants(String dbms) {

//当前只设置了 mysql 的驱动程序

if (dbms == "mysql") {

this.dbdriver = "org.gjt.mm.mysql.Driver";

this.dburl = "jdbc:mysql://localhost/" + this.database + "?useUnicode=true&characterEncoding=gb2312" + "&user=" + this.usr + "&password=" + this.passwd;

} else {

this.dbdriver = "none";

}

}

public static BeansConstants getInstance(String dbms) {

BeansConstants bc = new BeansConstants(dbms);

return bc;

}

public String getDatabase() { return this.database; }

public String getUsr() { return this.usr; }

public String getPasswd() { return this.passwd; }

public String getDbdriver() { return this.dbdriver; }

public String getDburl() { return this.dburl; }

public void setDatabase(String database) { this.database = database; }

public void setUsr(String usr) { this.usr = usr; }

public void setPasswd(String passwd) { this.passwd = passwd; }

public static void main(String[] args) {

BeansConstants CONST = BeansConstants.getInstance("mysql");

System.out.println("driver = " + CONST.dbdriver + "\nurl = " + CONST.dburl);

}

}

/*****************************

* 处理数据库的连接和访问

* @author javen

* @version 0.98

*****************************/

package net.asales.mysql;

import java.sql.*;

import java.io.*;

public class Mysql {

private Connection conn = null;

private Statement stmt = null;

private PreparedStatement prepstmt = null;

//这是一个全局类,里面放置数据库的参数,如数据库主机 访问用户名 密码等

private BeansConstants CONST = BeansConstants.getInstance("mysql");

/**

* 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);

}

/**

* PreparedStatement

* @return sql 预设SQL语句

*/

public void prepareStatement(String sql) throws SQLException {

prepstmt = conn.prepareStatement(sql);

}

public Connection getConn() { return this.conn; }

public Statement getStmt() { return this.stmt; }

public PreparedStatement getPrepstmt() { return this.prepstmt; }

/**

* 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;

}

}

//连接案例

<%@ page import="java.sql.*" %>

<jsp:useBean id="SQL" scope="session" class="net.asales.mysql.Mysql" />

sql = "SELECT * FROM table";

ResultSet rs = SQL.executeQuery(sql);

sql = "INSERT INTO table (id, name) values('', '')";

SQL.executeUpdate(sql);

 
 
 
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