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1 package example;
2
3 import java.io.PrintWriter  ;
4 import java.io.IOException ;
5
6 import java.sql.Connection ;
7 import java.sql.Statement ;
8 import java.sql.ResultSet ;
9 import java.sql.SQLException ;
10
11 import javax.servlet.GenericServlet ;
12 import javax.servlet.ServletRequest ;
13 import javax.servlet.ServletResponse ;
14 import javax.servlet.ServletException ;
15
16 public class SampleServlet extends GenericServlet {
17 public void init()
18 throws ServletException
19 {
20 try {
21 initDatabase(null);
22 } catch (Exception e) {
23 throw new ServletException (e);
24 }
25 }
26
27 @RequireConnection("jdbc/resin")
28 private void initDatabase(Connection conn)
29 throws SQLException
30 {
31 Statement stmt = conn.createStatement();
32
33 try {
34 ResultSet rs = stmt.executeQuery("SELECT name FROM aop_houses");
35 if (rs.next()) {
36 rs.close();
37 stmt.close();
38 return;
39 }
40 } catch (SQLException e) {
41 }
42
43 String sql = ("CREATE TABLE aop_houses (" +
44 " id INTEGER PRIMARY KEY auto_increment," +
45 " name VARCHAR(255)" +
46 ")");
47
48 stmt.executeUpdate(sql);
49
50 stmt.executeUpdate("INSERT INTO aop_houses (name) VALUES ('Gryffindor')");
51 stmt.executeUpdate("INSERT INTO aop_houses (name) VALUES ('Ravenclaw')");
52 stmt.executeUpdate("INSERT INTO aop_houses (name) VALUES ('Hufflepuff')");
53 stmt.executeUpdate("INSERT INTO aop_houses (name) VALUES ('Slytherin')");
54
55 stmt.close();
56 }
57
58 public void service(ServletRequest request,
59 ServletResponse response)
60 throws IOException , ServletException
61 {
62 response.setContentType("text/html");
63
64 PrintWriter out = response.getWriter();
65
66 try {
67 testConnection(out, null);
68 } catch (SQLException e) {
69 throw new ServletException (e);
70 }
71 }
72
73 @RequireConnection("jdbc/resin")
74 private void testConnection(PrintWriter out, Connection conn)
75 throws IOException , SQLException
76 {
77 Statement stmt = conn.createStatement();
78 ResultSet rs = stmt.executeQuery("SELECT id, name FROM aop_houses");
79
80 while (rs.next()) {
81 out.println(rs.getInt(1) + ": " + rs.getString(2) + "<br>");
82 }
83
84 rs.close();
85 stmt.close();
86 }
87 }
88 |
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Java API By Example, From Geeks To Geeks.