JDBCステートメントの例 – レコードのリストを選択する
次に、JDBCステートメントを使用してテーブルからレコード全体を選択し、ResultSetオブジェクトを介してすべてのレコードを表示する方法を示す例を示します。 selectクエリを発行するには、次のように `Statement.executeQuery`メソッドを呼び出します。
String selectTableSQL = "SELECT USER__ID, USERNAME from DBUSER";
Statement statement = dbConnection.createStatement();
ResultSet rs = statement.executeQuery(selectTableSQL);
while (rs.next()) {
String userid = rs.getString("USER__ID");
String username = rs.getString("USERNAME");
}
完全な例…
package com.mkyong.jdbc;
import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class JDBCStatementSelectExample {
private static final String DB__DRIVER = "oracle.jdbc.driver.OracleDriver";
private static final String DB__CONNECTION = "jdbc:oracle:thin:@localhost:1521:MKYONG";
private static final String DB__USER = "user";
private static final String DB__PASSWORD = "password";
public static void main(String[]argv) {
try {
selectRecordsFromDbUserTable();
} catch (SQLException e) {
System.out.println(e.getMessage());
}
}
private static void selectRecordsFromDbUserTable() throws SQLException {
Connection dbConnection = null;
Statement statement = null;
String selectTableSQL = "SELECT USER__ID, USERNAME from DBUSER";
try {
dbConnection = getDBConnection();
statement = dbConnection.createStatement();
System.out.println(selectTableSQL);
//execute select SQL stetement
ResultSet rs = statement.executeQuery(selectTableSQL);
while (rs.next()) {
String userid = rs.getString("USER__ID");
String username = rs.getString("USERNAME");
System.out.println("userid : " + userid);
System.out.println("username : " + username);
}
} catch (SQLException e) {
System.out.println(e.getMessage());
} finally {
if (statement != null) {
statement.close();
}
if (dbConnection != null) {
dbConnection.close();
}
}
}
private static Connection getDBConnection() {
Connection dbConnection = null;
try {
Class.forName(DB__DRIVER);
} catch (ClassNotFoundException e) {
System.out.println(e.getMessage());
}
try {
dbConnection = DriverManager.getConnection(DB__CONNECTION, DB__USER,
DB__PASSWORD);
return dbConnection;
} catch (SQLException e) {
System.out.println(e.getMessage());
}
return dbConnection;
}
}
