一、jdbc使用preparedStatement執行dql(查詢)語句示例

package edu.aeon.jdbc.crud;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import edu.aeon.aeonutils.AeonJdbcUtils;
/**
 * [說明]:使用jdbc進行資料操作
 * @author aeon
 */
public class
 
 JDBC_insert {
    /**
     * 使用jdbc進行增加操作(DML)
     */
    public static void jdbc_insert(){
        Connection connection=null;
        PreparedStatement preparedStatement = null;
        try {
            connection = AeonJdbcUtils.getMySqlConnection();
            String sql="insert into user(userid,username,userpw) values (?,?,?)";
            
 
//將sql語句進行預編譯然後儲存到preparedStatement物件中
            preparedStatement = connection.prepareStatement(sql);
            preparedStatement.setInt(1, 10006);
            preparedStatement.setString(2, "aeon");
            preparedStatement.setString(3, "aeon");
            int rowCount = preparedStatement.executeUpdate();
            System.out.println(rowCount
 
+"條資料被插入！");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }finally {
            AeonJdbcUtils.closeDB(null, preparedStatement, connection);
        }
    }
    /**
     * 查詢操作(DQL)
     * @param args
     */
    public static void jdbc_select(){
        Connection connection = null;
        PreparedStatement preparedStatement = null;
        ResultSet  resultSet = null;
        try {
            connection=AeonJdbcUtils.getMySqlConnection();
            String sql="select userid,username,userpw from user where userid > ?";
            preparedStatement=connection.prepareStatement(sql);
            preparedStatement.setInt(1, 10002);
            resultSet = preparedStatement.executeQuery();
            System.out.println("使用者id\t使用者名稱\t使用者密碼");
            while(resultSet.next()){
            int userid=resultSet.getInt("userid");
            String username=resultSet.getString("username");
            String userpw=resultSet.getString("userpw");
            System.out.println(userid+"\t"+username+"\t"+userpw);
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }finally{
            AeonJdbcUtils.closeDB(resultSet, preparedStatement, connection);
        }
    }
    public static void main(String[] args) {
        //jdbc_insert();
        jdbc_select();
    }
}

資料庫截圖：

執行結果截圖：