MySQL- 使用PreparedStatement接口,实现数据表的更新,查询操作

左手的ㄟ右手 2022-12-11 05:27 172阅读 0赞

## UPDATE ##

更新

package demo2;
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.PreparedStatement;
    import java.sql.SQLException;
     
    /* * 使用PreparedStatement接口,实现数据表的更新操作 */
     
    public class JDBCDemo { 
    	public static void main(String[] args) throws ClassNotFoundException,
    			SQLException { 
    		Class.forName("com.mysql.jdbc.Driver");
    		String url = "jdbc:mysql://localhost:3306/mybase";
    		Connection con = DriverManager.getConnection(url, "root", "root");
     
    		// SQL语句,参数采用问号占位符
    		String sql = "UPDATE sort SET name =?, sprice=?, sdesc=? WHERE id=?;";
     
    		// 调用数据库连接对象con的方法PreparedStatement获取sql语句的预编译对象
    		PreparedStatement pst = con.prepareStatement(sql);
    		// 调用pst的setXXX方法设置?占位符
    		pst.setObject(1, "汽车美容");
    		pst.setObject(2, 4000);
    		pst.setObject(3, "车坏了修");
    		pst.setObject(4, 6);
     
    		// 调用pst的方法执行sql语句
    		pst.executeUpdate();
     
    		// 释放资源
    		con.close();
    		pst.close();
    	}
    }

## SELECT ##

查询

package demo2;
     
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
     
    /* * 使用PreparedStatement接口,实现数据表的查询操作 */
    public class JDBCDemo2 { 
    	public static void main(String[] args) throws Exception { 
    		Class.forName("com.mysql.jdbc.Driver");
    		String url = "jdbc:mysql://localhost:3306/mybase";
    		Connection con = DriverManager.getConnection(url, "root", "root");
     
    		String sql = "SELECT * FROM `sort`;";
     
    		PreparedStatement pst = con.prepareStatement(sql);
     
    		// 调用pst对象的方法,返回结果集
    		ResultSet rs = pst.executeQuery();
    		// 遍历结果集
    		while (rs.next()) { 
    			System.out.println(rs.getString("id") + " "
    					+ rs.getString("name") + " " + rs.getString("sprice")
    					+ " " + rs.getString("sdesc"));
    		}
     
    		pst.close();
    		con.close();
    	}
    }