1 package jdbcDome;
  2 
  3 import java.sql.Connection;
  4 import java.sql.DriverManager;
  5 import java.sql.ResultSet;
  6 import java.sql.SQLException;
  7 import java.sql.Statement;
  8 
  9 /**
 10  * JDBC工具類
 11  * @author sunjian
 12  *
 13  */
 14 public class DBUtil {
 15     
 16     private static Connection conn = null;    //數(shù)據(jù)庫連接對象
 17     private Statement stmt = null;            //數(shù)據(jù)庫sql語句對象
 18     private ResultSet rs = null;            //數(shù)據(jù)庫結(jié)果集對象
 19     
 20     private static final String DRIVER="com.mysql.jdbc.Driver";//這是一個連接數(shù)據(jù)庫必填的常量
 21     private static final String URL = "jdbc:mysql://localhost:3308/shxt"; //數(shù)據(jù)庫的URL 3308為端口  shxt是那個數(shù)據(jù)庫
 22     private static final String USER = "root";  //數(shù)據(jù)庫的賬號
 23     private static final String PWD = "mysql";    //數(shù)據(jù)庫的密碼
 24     
 25     private static DBUtil db=null;
 26     
 27     public static DBUtil getDB() {
 28         //判斷是否為空，這樣的方式更加節(jié)省資源
 29         if(db == null) {
 30             db = new DBUtil();//實例化對象
 31         }
 32         return db;
 33     }
 34     //將構(gòu)造器隱藏，這樣就無法調(diào)用構(gòu)造器
 35     private DBUtil() {
 36         //................
 37     }
 38     
 39     
 40     //獲得數(shù)據(jù)庫連接，加載驅(qū)動
 41     public static Connection getConn() {
 42         //加載驅(qū)動
 43         try {
 44             Class.forName(DRIVER);
 45             try {
 46                 conn=DriverManager.getConnection(URL, USER, PWD);
 47             } catch (SQLException e) {
 48                 // TODO Auto-generated catch block
 49                 e.printStackTrace();
 50             }
 51         } catch (ClassNotFoundException e) {
 52             e.printStackTrace();
 53         }
 54         return conn;
 55     }
 56     
 57     //處理增刪改sql的方法
 58     public int update(String sql) {
 59         int num = 0;
 60         conn=getConn();
 61         try {
 62             stmt=conn.createStatement();
 63             num = stmt.executeUpdate(sql);
 64         } catch (SQLException e) {
 65             e.printStackTrace();
 66         }
 67         return num;
 68     }
 69     
 70     //處理查詢sql的方法
 71     public ResultSet query(String sql) {
 72         conn=getConn();
 73         try {
 74             stmt=conn.createStatement();
 75             rs=stmt.executeQuery(sql);
 76         } catch (SQLException e) {
 77             e.printStackTrace();
 78         }
 79         return rs;
 80     }
 81     
 82     //釋放資源的方法
 83     public void close() {
 84         try {
 85             if(rs != null) {
 86                 rs.close();
 87             }
 88             
 89             if(stmt != null) {
 90                 stmt.close();
 91             }
 92             
 93             if(conn != null) {
 94                 conn.close();
 95             }
 96         } catch (SQLException e) {
 97             e.printStackTrace();
 98         }
 99     }
100 }

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