package com.deng.test;

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

public class JDBCTest {

    public static void main(String[] args) {
        try {
            jdbcTest();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
	
    private static void jdbcTest() throws SQLException{
        Connection conn = null;
        PreparedStatement ps1 = null;
        PreparedStatement ps2 = null;
        PreparedStatement ps3 = null;

        try {
            String username = "test";//資料庫使用者名稱
            String password = "123456";//密碼
            String ip = "192.168.1.xxx";//IP地址
            String port = "1521";//oracle 埠  固定1521
            String instance = "orcl";//資料庫例項
			
            StringBuffer url = new StringBuffer();
            url.append("jdbc:oracle:thin:@");
            url.append(ip);
            url.append(":");
            url.append(port);
            url.append(":");
            url.append(instance);
			
            System.out.println("url = " + url.toString());
			
            Class.forName("oracle.jdbc.driver.OracleDriver");//載入Oracle驅動，需要引入Oracle驅動的jar包
            conn = DriverManager.getConnection(url.toString(),username,password);

            String sql = "select fid, fname from (select fid, fname from t_test_table order by fcreatetime desc) where rownum < 2";
            ps1 = conn.prepareStatement(sql);
            ResultSet rs1 = ps1.executeQuery();//執行查詢
            
            //返回結果用next()方法取出，一行用if，多行用while遍歷
            if(rs1.next()){
                String id = rs1.getString("fid");//通過列名獲取資料，或者通過cloumnIdex
//                String id = rs1.getString(1);
                System.out.println("beforeUpdate: name = " + rs1.getString("fname"));
                sql = "update t_test_table set fname = ? where fid = ? ";
                ps2 = conn.prepareStatement(sql);//預編譯
                ps2.setString(1, "修改之後");//傳參 從1開始 一個問號對應一個值
                ps2.setString(2, id);
                int effectRows = ps2.executeUpdate();

                System.out.println(effectRows);
				
                sql = "select fname from t_test_table where fid = ?";
                ps3 = conn.prepareStatement(sql);
                ps3.setString(1, id);
				
                ResultSet rs2 = ps3.executeQuery();

                if(rs2.next())
                System.out.println("afterUpdate:  name = " + rs2.getString("fname"));
				
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            //關閉連線
            if(conn != null)
                conn.close();
            if(ps1 != null)
                ps1.close();
            if(ps2 != null)
                ps2.close();
            if(ps3 != null)
                ps3.close();
        }
    }
}