|
| |
| 20. 13. 1. 演示Preparedstatement |
|
|
When your SQL query is parameterized, you should use a PreparedStatement object.
A PreparedStatement object enables you to pass input parameters to the SQL statement before sending it to the database server for execution. |
|
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.Statement;
public class Main {
public static void main(String[] args) throws Exception {
Connection conn = getConnection();
Statement st = conn
.createStatement();
st.executeUpdate("create table survey (id int, myDate TIMESTAMP );");
String INSERT_RECORD = "insert into survey(id) values(?)";
PreparedStatement pstmt = conn.prepareStatement(INSERT_RECORD);
pstmt.setString(1, "1");
pstmt.executeUpdate();
ResultSet rs = st.executeQuery("SELECT * FROM survey");
outputResultSet(rs);
pstmt.setString(1, "2");
pstmt.executeUpdate();
rs = st.executeQuery("SELECT * FROM survey");
outputResultSet(rs);
rs.close();
st.close();
conn.close();
}
private static void outputResultSet(ResultSet rs) throws Exception {
ResultSetMetaData rsMetaData = rs.getMetaData();
int numberOfColumns = rsMetaData.getColumnCount();
for (int i = 1; i < numberOfColumns + 1; i++) {
String columnName = rsMetaData.getColumnName(i);
System.out.print(columnName + " ");
}
System.out.println();
System.out.println("----------------------");
while (rs.next()) {
for (int i = 1; i < numberOfColumns + 1; i++) {
System.out.print(rs.getString(i) + " ");
}
System.out.println();
}
}
private static Connection getConnection() throws Exception {
Class.forName("org.hsqldb.jdbcDriver");
String url = "jdbc:hsqldb:mem:data/tutorial";
return DriverManager.getConnection(url, "sa", "");
}
}
|
|
ID MYDATE
----------------------
1 null
ID MYDATE
----------------------
1 null
2 null |
|