1，jdbc.properties文件

driverClassName=oracle.jdbc.driver.OracleDriver
url=jdbc:oracle:thin:@localhost:1521:BDQN
username=wjb
password=wjb

2柠偶，讀取properties文件

package cn.util;

import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

public class ConfigManager {
    //讀取jdbc.properties配置文件,單例模式 
    
    private static ConfigManager configManager;
    private static Properties properties;
    
    //單例模式必須用private構造方法，不能用public
    private ConfigManager(){
        String configFile = "jdbc.properties";
        properties = new Properties();
        InputStream is = ConfigManager.class.getClassLoader().getResourceAsStream(configFile);
        try {
            properties.load(is);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    
    //提供一個入口獲取ConfigManager,這個方法可以嚴格控制實例生成的個數(shù)
    public static ConfigManager getInstance(){
        //如果為空就創(chuàng)建一個自已的構造方法睬关，獲取ConfigManager
        if(configManager == null){
            configManager = new ConfigManager();
        }
        return configManager;
    }
    
    //以上只是獲取了properties的KEY值诱担，下面這個方法獲取對應的value值
    public String getString (String key){
        return properties.getProperty(key);
    }
    
}

3，連接數(shù)據(jù)庫的基類

package cn.dao;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import cn.pojo.Dancer;
import cn.util.ConfigManager;

public class BaseDao {
    Connection connection = null;
    ResultSet rs = null;
    PreparedStatement pst = null;
    
//連接數(shù)據(jù)庫的方法
    public boolean getConnection(){
        String driver = ConfigManager.getInstance().getString("driverClassName");
        String url = ConfigManager.getInstance().getString("url");
        String username = ConfigManager.getInstance().getString("username");
        String password = ConfigManager.getInstance().getString("password");
        
        try {
            Class.forName(driver);
            connection = DriverManager.getConnection(url, username, password);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        
        return true;
    }
    
    //增刪改
    public int executeUpdate(String sql,Object[] param){
        int row = 0;
        if(this.getConnection()){
            try {
                pst = connection.prepareStatement(sql);
                for(int i = 0;i<param.length;i++){
                    pst.setObject(i+1, param[i]);
                }
                row = pst.executeUpdate();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        return row;
    }
    
    //查詢
    public ResultSet executeQuery(String sql,Object[] param){
        if(this.getConnection()){
            try {
                pst = connection.prepareStatement(sql);
                for(int i=0;i<param.length;i++){
                    pst.setObject(i+1, param[i]);
                }
                rs = pst.executeQuery();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        
        return rs;
    }
    
    
}