<![CDATA[
import java.sql.*;
/**
* Driver class that runs sample JDBC code on a MySQL database
*
* Get MySQL at: http://dev.mysql.com/downloads/mysql/5.0.html
* Get the MySQL JDBC at:
* http://dev.mysql.com/downloads/connector/j/3.1.html
*
* Be sure to include the MySQL JDBC .jar file as an external library
* in this Eclipse project (right click on this project, select
* "Properties." Go-to Java Buildpath, select the "Libraries" tab,
* and click the "External JAR" button.
*
* @author Alex Loddengaard (lodbot@cs)
*
*/
public class Main {
/**
* Performs sample operations on the "test" database
* @param args command-line arguments (ignored)
* @throws RuntimeException if anything goes wrong when
* interfacing with MySQL
*/
public static void main(String[] args) {
Connection conn = getConnection();
//insert a "Katie Holmes" row into the "actors" table
modifyQuery(conn, "INSERT INTO actors " +
"VALUES (2, 'Katie Holmes', 'F')");
//query for all actors
ResultSet results = selectQuery(conn, "SELECT * " +
"FROM actors");
try {
//loop through each row returned by the query and
//print the name and id
while (results.next())
System.out.println(results.getInt("id") + " " + results.getString("name"));
} catch (SQLException e) {
throw new RuntimeException("Error getting results: " + e);
}
//delete the "Katie Holmes" row from the actors table
modifyQuery(conn, "DELETE FROM actors " +
"WHERE name = 'Katie Holmes'");
}
/**
* Connects to MySQL using the MySQL JDBC driver
* and returns a connection to the database
* @return a connection to the database
* @throws RuntimeException if an error occurs connecting to the database
*/
private static Connection getConnection() {
//MySQL connection parameters
String userName = "test";
String password = "test";
//host: localhost and database: test
//host can be localhost, google.com, 192.168.1.100, etc
String url = "jdbc:mysql://localhost/test";
try {
//create a new instance of a Driver implementation
Class.forName("com.mysql.jdbc.Driver").newInstance();
//have the DriverManager use each loaded Driver implementation to connect
//with the given url, userName, and password
Connection conn = DriverManager.getConnection(url, userName, password);
return conn;
} catch (Exception e) {
throw new RuntimeException("Error connecting to database: " + e);
}
}
/**
* Queries the database using SELECT queries only and returns the results of the query
* @param conn The database connection
* @param query The SQL query string - only a SELECT query
* @return A ResultSet that contains the rows returned by the query
* @throws RuntimeException if the SQL query string is incorrect
*/
private static ResultSet selectQuery(Connection conn, String query) {
try {
PreparedStatement st = conn.prepareStatement(query);
ResultSet rs = st.executeQuery();
return rs;
} catch (SQLException e) {
throw new RuntimeException("Error querying: " + e.getMessage());
}
}
/**
* Queries the database using anything othe than SELECT queries
* and returns the results of the query
* @param conn The database connection
* @param query The SQL query string - any non-SELECT query
* @throws RuntimeException if the SQL query string is incorrect
*/
private static void modifyQuery(Connection conn, String query) {
try {
PreparedStatement st = conn.prepareStatement(query);
st.executeUpdate();
} catch (SQLException e) {
throw new RuntimeException("Error querying: " + e.getMessage());
}
}
}
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