jdbc操作mysql数据库

淩亂°似流年 2022-08-13 12:46 239阅读 0赞

package jdbc.demo;
    
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import java.sql.Statement;
    
    import org.junit.Test;
    
    
    public class Demo1 {
    	/*
    	 * 操作一
    	 */
    	@Test
    	public void fun() throws ClassNotFoundException, SQLException{
    		
    		Class.forName("com.mysql.jdbc.Driver");
    		String url = "jdbc:mysql://localhost:3306/mydb1";
    		String username = "root";
    		String password = "123";
    		//注意包要导正确
    		Connection con = DriverManager.getConnection(url, username, password);
    //		System.out.println(con);
    		
    		//进行对数据库操作
    		Statement stmt = con.createStatement();
    		//插入  只能写一条，不用加分号
    		String sql = "insert into stu values('0003','haha',16,'male')";
    		//影响了几行
    		int r = stmt.executeUpdate(sql);
    		System.out.println(r);
    	}
    	
    	/*
    	 * 查询
    	 */
    	@Test
    	public void fun2() throws ClassNotFoundException, SQLException{
    		Class.forName("com.mysql.jdbc.Driver");
    		String url = "jdbc:mysql://localhost:3306/mydb1";
    		String username = "root";
    		String password = "123";
    		
    		Connection con = DriverManager.getConnection(url, username, password);
    		
    		Statement stmt = con.createStatement();
    
    		String qSql = "select * from stu";
    		//必须是查询语句
    		ResultSet rs = stmt.executeQuery(qSql);
    		while(rs.next()){
    			//通过列编号获取值
    			String num = rs.getString(1);
    			String name = rs.getString(2);
    			int age = rs.getInt(3);
    			String gender = rs.getString(4);
    			
    			System.out.println(num+","+name+","+age+","+gender);
    		}
    		
    		/*
    		 * 关闭资源
    		 * 倒关
    		 */
    		rs.close();
    		stmt.close();
    		con.close();
    	}
    	
    	/*
    	 * 规范化，
    	 * 在try外引用，try里实例化，finally中关闭，关闭时要进行判断是否为空
    	 */
    	
    }