JDBC簡單連接Oracle

JDBC

The JDBC API is a Java API that can access any kind of tabular data, especially data stored in a Relational Database.

JDBC helps you to write Java applications that manage these three programming activities:

• Connect to a data source, like a database
• Send queries and update statements to the database。
• Retrieve and process the results received from the database in answer to your query

package jdbc;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
public class jdbc_exp {

public static void main(String[] args) {
    Connection con = null;// 創建一個數據庫連接
    PreparedStatement pre = null;// 創建預編譯語句對象，一般都是用這個而不用Statement
    ResultSet result = null;// 創建一個結果集對象
    try
    {
        Class.forName("oracle.jdbc.driver.OracleDriver");// 加載Oracle驅動程序
        System.out.println("開始嘗試連接數據庫！");
        String url = "jdbc:oracle:" + "thin:@10.224.188.188:1521:tonytest";// 127.0.0.1是本機地址，XE是精簡版Oracle的默認數據庫名
        String user = "hr";// 用戶名,系統默認的賬戶名
        String password = "CCM%lab123";// 你安裝時選設置的密碼
        con = DriverManager.getConnection(url, user, password);// 獲取連接
        System.out.println("連接成功！");
        String sql = "select * from dept order by 1";// 預編譯語句，“？”代表參數
        pre = con.prepareStatement(sql);// 實例化預編譯語句
        result = pre.executeQuery();// 執行查詢，注意括號中不需要再加參數
        while (result.next())
            // 當結果集不為空時
            System.out.println("deptno: " + result.getInt("deptno") + " dname: "
                    + result.getString("dname") + " loc: " + result.getString("loc")
                    + " create_date: " + result.getString("create_date"));
    }
    catch (Exception e)
    {
        e.printStackTrace();
    }
    finally
    {
        try
        {
            // 逐一將上面的幾個對象關閉，因為不關閉的話會影響性能、并且占用資源
            // 注意關閉的順序，最后使用的最先關閉
            if (result != null)
                result.close();
            if (pre != null)
                pre.close();
            if (con != null)
                con.close();
            System.out.println("數據庫連接已關閉！");
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }

}


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