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);