Java写的常用数据库的访问类

DB类是项目用来连接数据库的辅助类：

封装和数据库的连接。

主要是和数据库连接的相关信息：

1.找到驱动程序

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

 

2.连接字符串

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

 

3.PreparedStatement

 

4. Statement

 

5. Result

 

 

package com.bjsxt.shopping.util;

import java.sql.*;

 

publicclass DB {

    publicstatic Connection getConn() {

       Connection conn = null;

       try {

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

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

       } catch (ClassNotFoundException e) {

           e.printStackTrace();

       } catch (SQLException e) {

           e.printStackTrace();

       }

      

       return conn;

    }

   

    publicstatic PreparedStatement prepare(Connection conn,  String sql) {

       PreparedStatement pstmt = null;

       try {

           if(conn != null) {

              pstmt = conn.prepareStatement(sql);

           }

       } catch (SQLException e) {

           e.printStackTrace();

       }

       return pstmt;

    }

   

    publicstatic PreparedStatement prepare(Connection conn,  String sql, int autoGenereatedKeys) {

       PreparedStatement pstmt = null;

       try {

           if(conn != null) {

              pstmt = conn.prepareStatement(sql, autoGenereatedKeys);

           }

       } catch (SQLException e) {

           e.printStackTrace();

       }

       return pstmt;

    }

   

    publicstatic Statement getStatement(Connection conn) {

       Statement stmt = null;

       try {

           if(conn != null) {

              stmt = conn.createStatement();

           }

       } catch (SQLException e) {

           e.printStackTrace();

       }

       return stmt;

    }

   

    /*

    public static ResultSet getResultSet(Connection conn, String sql){

       Statement stmt = getStatement(conn);

       ResultSet rs = getResultSet(stmt, sql);

       close(stmt);

       return rs;

    }

    */

   

    publicstatic ResultSet getResultSet(Statement stmt, String sql) {

       ResultSet rs = null;

       try {

           if(stmt != null) {

              rs = stmt.executeQuery(sql);

           }

       } catch (SQLException e) {

           e.printStackTrace();

       }

       return rs;

    }

   

    publicstaticvoid executeUpdate(Statement stmt, String sql) {

       try {

           if(stmt != null) {

              stmt.executeUpdate(sql);

           }

       } catch (SQLException e) {

           e.printStackTrace();

       }

    }

   

    publicstaticvoid close(Connection conn) {

       try {

           if(conn != null) {

              conn.close();

              conn = null;

           }

       } catch (SQLException e) {

           e.printStackTrace();

       }

    }

   

    publicstaticvoid close(Statement stmt) {

       try {

           if(stmt != null) {

              stmt.close();

              stmt = null;

           }

       } catch (SQLException e) {

           e.printStackTrace();

       }

    }

   

    publicstaticvoid close(ResultSet rs) {

       try {

           if(rs != null) {

              rs.close();

              rs = null;

           }

       } catch (SQLException e) {

           e.printStackTrace();

       }

    }

}