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1
43
44 package foo;
45
46 import java.sql.PreparedStatement  ;
47 import java.sql.ResultSet ;
48 import java.sql.Statement ;
49
50 import javax.naming.Context ;
51 import javax.naming.InitialContext ;
52 import javax.sql.DataSource ;
53 import javax.transaction.UserTransaction ;
54
55 public class DBTest{
56
57 int foo = -1;
58
60 public void init(String completion) {
61 try{
62 Context ctx = new InitialContext ();
63
64 DataSource ds =
66 (DataSource )ctx.lookup("java:comp/env/jdbc/myDB");
67
68 UserTransaction ut = (UserTransaction )ctx.lookup("java:comp/UserTransaction");
69
70 java.sql.Connection conn = ds.getConnection();
71
72 System.out.println("<<< beginning the transaction >>>");
73 ut.begin();
74
75 Statement stmt = conn.createStatement();
77 ResultSet rst =
78 stmt.executeQuery("select id, foo from testdata");
79 if(rst.next()) {
80 foo=rst.getInt(2);
81 }
82 System.out.println("foo = "+ foo +" (before completion)");
83
84 PreparedStatement pstmt = conn.prepareStatement("update testdata set foo=? where id=1");
85 pstmt.setInt(1,++foo);
86 pstmt.executeUpdate();
87
88 if (completion != null && completion.equals("commit")) {
89 System.out.println("<<< committing the transaction >>>");
90 ut.commit();
91 } else {
92 System.out.println("<<< rolling back the transaction >>>");
93 ut.rollback();
94 }
95
96 rst =
98 stmt.executeQuery("select id, foo from testdata");
99 if(rst.next()) {
100 foo=rst.getInt(2);
101 }
102 System.out.println("foo = "+ foo +" (after completion)");
103
104 conn.close();
105 System.out.println("<<< done >>>");
106 }catch(Exception e) {
107 System.out.print("DBTest >> ");
108 e.printStackTrace();
109 }
110 }
111
112 public String getFoo() { return ""+foo; }
113 }
114
115 |
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