一、通用数据类
二、增加数据
三、查询数据
======通用数据类===========================
package com.sss.util; import java.sql.*; public class DB { public static Connection getConn() { Connection conn = null; try { Class.forName("com.mysql.jdbc.Driver"); conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/smud","root","root"); } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); } return conn; } public static PreparedStatement prepare(Connection conn, String sql) { PreparedStatement pstmt = null; try { if(conn != null) { pstmt = conn.prepareStatement(sql); } } catch (SQLException e) { e.printStackTrace(); } return pstmt; } public static 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; } public static 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; } */ public static ResultSet getResultSet(Statement stmt, String sql) { ResultSet rs = null; try { if(stmt != null) { rs = stmt.executeQuery(sql); } } catch (SQLException e) { e.printStackTrace(); } return rs; } public static void executeUpdate(Statement stmt, String sql) { try { if(stmt != null) { stmt.executeUpdate(sql); } } catch (SQLException e) { e.printStackTrace(); } } public static void close(Connection conn) { try { if(conn != null) { conn.close(); conn = null; } } catch (SQLException e) { e.printStackTrace(); } } public static void close(Statement stmt) { try { if(stmt != null) { stmt.close(); stmt = null; } } catch (SQLException e) { e.printStackTrace(); } } public static void close(ResultSet rs) { try { if(rs != null) { rs.close(); rs = null; } } catch (SQLException e) { e.printStackTrace(); } } public static void close(ResultSet rs,Statement stmt,Connection conn) { try { if(rs != null) { rs.close(); rs = null; } if(stmt != null) { stmt.close(); stmt = null; } if(conn != null) { conn.close(); conn = null; } } catch (SQLException e) { e.printStackTrace(); } } }