j2ee 连接数据库封装起来的类

最新推荐文章于 2025-12-19 16:00:26 发布

最新推荐文章于 2025-12-19 16:00:26 发布 · 90 阅读

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本文提供了一个使用 Java 连接 MySQL 数据库的简单示例代码，包括加载 JDBC 驱动、建立数据库连接、创建 Statement 和 PreparedStatement 对象、执行 SQL 查询以及关闭连接等操作。

import java.sql.*;

public class DB {

    

    static {

       try {

           Class.forName("com.mysql.jdbc.Driver");

       } catch (ClassNotFoundException e) {

           e.printStackTrace();

       }

    }

    

    private static Connection getConn() {

       Connection conn = null;

       try {

           conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydata?user=root&password=root");

       } catch (SQLException e) {

           e.printStackTrace();

       }

       return conn;

    }

    

    private static Statement getStmt(Connection conn) {

       Statement stmt = null;

       try {

           stmt = conn.createStatement();

       } catch (SQLException e) {

           e.printStackTrace();

       }

       return stmt;

    }

    

    private static PreparedStatement getPStmt(Connection conn, String sql) {

       PreparedStatement pStmt =null;

       try {

           pStmt = conn.prepareStatement(sql);

       } catch (SQLException e) {

           e.printStackTrace();

       }

       return pStmt;

    }

    

    private static ResultSet executeQuery(Statement stmt, String sql) {

       ResultSet rs = null;

       try {

           rs = stmt.executeQuery(sql);

       } catch (SQLException e) {

           e.printStackTrace();

       }

       return rs;

    }

    

    private void closeConn(Connection conn) {

       if(conn!=null) {

           try {

              conn.close();

           } catch (SQLException e) {

              e.printStackTrace();

           }

           conn = null;

       }

    }

    

    private void closeStmt(Statement stmt) {

       if(stmt!=null) {

           try {

              stmt.close();

           } catch (SQLException e) {

              e.printStackTrace();

           }

           stmt = null;

       }

    }

    

    private void closePStmt(Statement pStmt) {

       if(pStmt !=null) {

           try {

              pStmt.close();

           } catch (SQLException e) {

              e.printStackTrace();

           }

           pStmt = null;

       }

    }

    

    private void closeRs(ResultSet rs) {

       if(rs !=null) {

           try {

              rs.close();

           } catch (SQLException e) {

              e.printStackTrace();

           }

           rs = null;

       }

    }

}