Java之oracle數據庫連接和MySQL數據庫連接

Java連接數據庫需要加載對應的數據庫驅動。驅動的話自己去下載，然後按如圖所示添加到項目中。

oracle數據庫連接：

package 數據庫連接測試;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

public class oracle測試 {

	final static String DRIVER = "oracle.jdbc.OracleDriver";
	final static String URL = "jdbc:oracle:thin:@localhost:1521:orcl";
	final static String USERNAME = "SCOTT";
	final static String PASSWORD = "tiger";

	public List queryInfo() {
		Connection conn = null;
		Statement stmt = null;
		ResultSet rs = null;
		List<String> list = new ArrayList<>();

		try {
			// 1加載數據庫驅動
			Class.forName(DRIVER);
			// 2獲取數據庫連接
			conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
			// 3通過連接，獲取一個Statement的對象，用來操作數據庫
			String sql = "select * from emp";
			stmt = conn.createStatement();
			rs = stmt.executeQuery(sql);
			while (rs.next()) {
				String name = rs.getString("ename");
				list.add(name);
			}
		} catch (SQLException | ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally {
			if (conn != null) {
				try {
					conn.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			if (rs != null) {
				try {
					rs.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			if (stmt != null) {
				try {
					stmt.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}

		return list;
	}

	public static void main(String[] args) {
		oracle測試 oo = new oracle測試();
		List<String> list = oo.queryInfo();
		for (String name : list) {
			System.out.println(name);
		}
	}

}

MySQL數據庫連接：

package 數據庫連接測試;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

public class mysql連接 {

	final static String DRIVER = "com.mysql.jdbc.Driver";
	final static String URL = "jdbc:mysql://localhost:3306/shop";
	final static String user = "root";
	final static String password = "";

	public List queryInfo() {

		List list = new ArrayList<String>();
		Statement stmt = null;
		ResultSet rs = null;
		Connection conn = null;
		try {
			Class.forName(DRIVER);
			conn = DriverManager.getConnection(URL, user, password);
		
//			判斷是否成功連接到數據庫
//			if (!conn.isClosed())
//				System.out.println("Succeeded connecting to the Database!");
			
			stmt = conn.createStatement();
			rs = stmt.executeQuery("SELECT * FROM admin");
			while (rs.next()) {
				String name = rs.getString("username");
				list.add(name);
			}

		} catch (SQLException | ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}finally {
			if(rs != null){
				try {
					rs.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			if(conn != null){
				try {
					conn.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			if(stmt != null){
				try {
					stmt.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}
		return list;
	}

	public static void main(String[] args) {
		mysql連接 mm = new mysql連接();
		List<String> list = new ArrayList();
		list = mm.queryInfo();
		for (String name : list) {
			System.out.println(name);
		}
	}
}