自写的mysqljdbc程序

连接mysql数据库：mydata

 1 import java.sql.*;
 2 
 3 public class TestMysqlConnection {
 4 
 5     /**
 6      * @param args
 7      */
 8     public static void main(String[] args) {
 9         Connection con=null;
10         PreparedStatement pSta=null;
11         ResultSet rs=null;
12         con = DBManager.getConnection();
13         String sql = "select * from dept";
14         try {
15             pSta = con.prepareStatement(sql);
16             rs = pSta.executeQuery();
17             while (rs.next()) {
18                 int depno = rs.getInt("depno");
19                 String dname = rs.getString("dname");
20                 String loc = rs.getString("loc");
21                 System.out.println(depno + "--" + dname + "--" + loc);
22             }
23         } catch (SQLException e) {
24             // TODO Auto-generated catch block
25             e.printStackTrace();
26         }finally{
27             DBManager.closeResultSet(rs);
28             DBManager.closeStatement(pSta);
29             DBManager.closeConnection(con);
30         }
31     }
32 }
33 
34 class DBManager {
35     public static Connection getConnection() {
36         Connection con = null;
37         
38         try {
39             Class.forName("com.mysql.jdbc.Driver");
40             con = DriverManager
41                     .getConnection("jdbc:mysql://localhost:3306/mydata?user=root&password=root");
42         } catch (ClassNotFoundException e) {
43             // TODO Auto-generated catch block
44             e.printStackTrace();
45         } catch (SQLException e) {
46             // TODO Auto-generated catch block
47             e.printStackTrace();
48         }
49         return con;
50     }
51 
52     public static void closeResultSet(ResultSet rs) {
53         try {
54             if (rs != null) {
55                 rs.close();
56                 rs = null;
57             }
58         } catch (SQLException e) {
59             // TODO Auto-generated catch block
60             e.printStackTrace();
61         }
62     }
63 
64     public static void closeStatement(PreparedStatement pSta) {
65         try {
66             if (pSta != null) {
67                 pSta.close();
68                 pSta = null;
69             }
70         } catch (SQLException e) {
71             // TODO Auto-generated catch block
72             e.printStackTrace();
73         }
74     }
75 
76     public static void closeConnection(Connection con) {
77         try {
78             if (con != null && !con.isClosed()) {
79                 con.close();
80             }
81         } catch (SQLException e) {
82             // TODO Auto-generated catch block
83             e.printStackTrace();
84         }
85     }
86 
87 }

PreparedStatement接口继承自Statement接口，PreparedStatement实例包含已编译的SQL语句，且SQL语句可以有输入参数。这些输入参数在SQL语句创建时并未被指定，而是为每个输入参
数保留一个问号作为占位符。在执行PreparedStatement对象之前，必须通过setXXX方法来设置每个输入参数的值。例如：
　　pSta.setInt(1,1);就是为第一个参数设置整型值1.
　　pSta.setString(2,"博客园");就是为第二个参数设置String类型值"博客园".