jdbc.driver_class=oracle.jdbc.driver.OracleDriver jdbc.connection.url=jdbc:oracle:thin:@localhost:1521:orcl jdbc.connection.username=scott jdbc.connection.password=tiger

import java.io.IOException; import java.io.InputStream; import java.util.Properties; //读取配置文件（属性文件）的工具类 public class ConfigManager {  private static ConfigManager configManager;  // properties.load(inputStream);读取属性文件  private static Properties properties;  // 在构造工具类时，进行配置文件的读取  private ConfigManager() {   String configFile = "database.properties";   properties = new Properties();   InputStream is = ConfigManager.class.getClassLoader()     .getResourceAsStream(configFile);   try {    // 读取配置文件    properties.load(is);    is.close();   } catch (IOException e) {    e.printStackTrace();   }  }  // 通过单例模式设置实例化个数  public static ConfigManager getInstance() {   if (configManager == null) {    configManager = new ConfigManager();   }   return configManager;  }  // 通过key获取对应的value  public String getString(String key) {   return properties.getProperty(key);  } }

import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import com.book.util.ConfigManager; //基类：数据库操作通用类 public class BaseDao {  protected Connection conn;  protected PreparedStatement ps;  protected Statement stmt;  protected ResultSet rs;  // 获取数据库连接  public boolean getConnection() {   // // 读取配置信息   String driver = ConfigManager.getInstance().getString(     "jdbc.driver_class");   String url = ConfigManager.getInstance().getString(     "jdbc.connection.url");   String username = ConfigManager.getInstance().getString(     "jdbc.connection.username");   String password = ConfigManager.getInstance().getString(     "jdbc.connection.password");   // 加载JDBC驱动   try {    Class.forName(driver);    // 与数据库建立连接    conn = DriverManager.getConnection(url, username, password);   } catch (ClassNotFoundException e) {    return false;   } catch (SQLException e) {    return false;   }   return true;  }  // 增删改的通用方法  public int executeUpdate(String sql, Object[] params) {   int updateRows = 0;   getConnection();   try {    ps = conn.prepareStatement(sql);    // 填充占位符    for (int i = 0; i < params.length; i++) {     ps.setObject(i + 1, params[i]);     System.out.println(i + 1 + "---" + params[i]);    }    System.out.println(sql);    updateRows = ps.executeUpdate();   } catch (SQLException e) {    e.printStackTrace();   }   return updateRows;  }  // 查询  public ResultSet executeSQL(String sql, Object[] params) {   getConnection();   try {    ps = conn.prepareStatement(sql);    // 填充占位符    for (int i = 0; i < params.length; i++) {     ps.setObject(i + 1, params[i]);    }    rs = ps.executeQuery();   } catch (SQLException e) {    e.printStackTrace();   }   return rs;  }  // 关闭资源  public void closeAll(){   try {    if(rs!=null){     rs.close();    }    if(stmt!=null){     stmt.close();    }    if(ps!=null){     ps.close();    }    if(conn!=null){     conn.close();    }   } catch (SQLException e) {    e.printStackTrace();   }  } }