Java Reference
In-Depth Information
You can use the
getColumnCount()
method to find the number of columns in the result and
the
getColumnName(int)
method to get the column names. For example, ListingĀ 32.7 dis-
plays all the column names and contents resulting from the SQL SELECT statement
select
* from Enrollment
. The output is shown in FigureĀ 32.26.
L
ISTING
32.7
TestResultSetMetaData.java
1
import
java.sql.*;
2
3
public class
TestResultSetMetaData {
4
public static void
main(String[] args)
5
throws
SQLException, ClassNotFoundException {
6
// Load the JDBC driver
7 Class.forName(
"com.mysql.jdbc.Driver"
);
8 System.out.println(
"Driver loaded"
);
9
10
// Connect to a database
11 Connection connection = DriverManager.getConnection
12 (
"jdbc:mysql://localhost/javabook"
,
"scott"
,
"tiger"
);
13 System.out.println(
"Database connected"
);
14
15
// Create a statement
16 Statement statement = connection.createStatement();
17
18
// Execute a statement
19 ResultSet resultSet = statement.executeQuery
20 (
"select * from Enrollment"
);
21
22 ResultSetMetaData rsMetaData = resultSet.getMetaData();
23
for
(
int
i =
1
; i <= rsMetaData.getColumnCount(); i++)
24 System.out.printf(
"%-12s\t"
, rsMetaData.getColumnName(i));
25 System.out.println();
26
27
// Iterate through the result and print the students' names
28
while
(resultSet.next()) {
29
for
(
int
i =
1
; i <= rsMetaData.getColumnCount(); i++)
30 System.out.printf(
"%-12s\t"
, resultSet.getObject(i));
31 System.out.println();
32 }
33
34
// Close the connection
35 connection.close();
36 }
37 }
load driver
connect database
create statement
create result set
result set metadata
column count
column name
F
IGURE
32.26
The
ResultSetMetaData
interface enables you to obtain result set
information.
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