J2EE 中的数据库连接类

关键字: jdbc 数据库 java j2ee
1.DBConfig.properties
Properties代码
#属性文件，存放JDBC联接数据库的参数  
#sql2005驱动  
#DataBaseDriver = com.microsoft.sqlserver.jdbc.SQLServerDriver  
#DataBaseURL = jdbc:sqlserver://localhost:1433;SelectMode=cursor;DatabaseName=drp  
#DataBaseUser = sa  
#DataBaseUserPassword =   
 
#mysql驱动  
DataBaseDriver = com.mysql.jdbc.Driver  
DataBaseURL = jdbc:mysql://localhost:3306/drp  
DataBaseUser = root  
DataBaseUserPassword = root 

2.DBConnectionException.java

Java代码
package com.mp.struts.util;  
 
/** 
* 该异常类用来封装联接数据库时可能出现的异常 
* @author  黄良宝
* 
*/ 
@SuppressWarnings("serial")  
public class DBConnectionException extends Exception{  
    public DBConnectionException(String message) {  
        super(message);  
    }  
} 
package com.mp.struts.util;

/**
* 该异常类用来封装联接数据库时可能出现的异常
* @author  黄良宝
*
*/
@SuppressWarnings("serial")
public class DBConnectionException extends Exception{
public DBConnectionException(String message) {
super(message);
}
}

3.DBConnection.java
Java代码
package com.mp.struts.util;  
import java.io.InputStream;  
import java.io.IOException;  
import java.sql.*;  
import java.util.Properties;  
 
/** 
* 实用工具类,获得通过JDBC联接数据库的联接对象. 
* 联接数据库所需的参数放在资源属性文件DBConfig.properties中, 
* 该文件位于类路径的根目录下 
* @author  黄良宝
* 
*/ 
public class DBConnection {  
 
    private static String CONFIG_FILENAME = "DBConfig.properties";  
    private static String driverName = "";  
    private static String url = "";  
    private static String user = "";  
    private static String password = "";  
 
 
    /** 
     * 返回数据库联接 
     *  
     * @return Connection 
     * @throws DBConnectionException  
     * @throws SQLException  
     * @throws SQLException 
     */ 
    public static Connection getConnection() throws DBConnectionException, SQLException {  
        Properties prop = new Properties();  
 
        // 读取配置文件信息  
        InputStream in = DBConnection.class.getResourceAsStream("/" 
                + CONFIG_FILENAME);  
          
        Connection conn = null;  
        try {  
            //装载属性文件  
            prop.load(in);  
            //从属性文件中读取JDBC联接数据库的参数  
            driverName = prop.getProperty("DataBaseDriver");  
            user = prop.getProperty("DataBaseUser");// 用户,口令  
            password = prop.getProperty("DataBaseUserPassword");//口令  
            url = prop.getProperty("DataBaseURL");// url  
            // 装载驱动程序  
            Class.forName(driverName);  
            conn = DriverManager.getConnection(url, user, password);  
        } catch (IOException e) {  
            throw new DBConnectionException("装载数据库配置文件" + CONFIG_FILENAME  
                    + "时错误!");  
        } catch (ClassNotFoundException e) {  
            throw new DBConnectionException("装载驱动程序" + driverName + "时错误!");  
        }  
        return conn;  
    }  
      
    /** 
     *  
     * @param conn 
     * @throws SQLException 
     */ 
    public static void closeConn(Connection conn) throws SQLException {  
        if(conn != null) {  
            conn.close();  
            conn = null;  
        }  
    }  
 
    /** 
     *  
     * @param stmt 
     * @throws SQLException 
     */ 
    public static void closeStmt(Statement stmt) throws SQLException {  
        if(stmt != null) {  
            stmt.close();  
            stmt = null;  
        }  
    }  
      
    /** 
     *  
     * @param rs 
     * @throws SQLException 
     */ 
    public static void closeRs(ResultSet rs) throws SQLException {  
        if(rs != null) {  
            rs.close();  
            rs = null;  
        }  
    }  
    /** 
     * 测试主函数 
     * 如果未抛出异常则说明正确 
     * @param args 
     * @throws Exception 
     */ 
    public static void main(String[] args) throws Exception {  
          
        Connection conn = DBConnection.getConnection();  
        System.out.println("Connection -"+ conn.getCatalog() +" OK!");  
        DBConnection.closeConn(conn);  
        System.out.println("Connection is closed! now connection = " + conn.getCatalog());  
    }  
}