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对于之前的处理数据库的方法有大量代码是相同的，如注册驱动，建立连接，关闭连接

package cn.edu.hbue.wmp;import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;public class JDBCUtil {   	static{   		try {   			Class.forName("com.mysql.cj.jdbc.Driver");		} catch (ClassNotFoundException e) {   			System.out.println("JDBC driver error");			e.printStackTrace();		}	}		public static Connection getConn() {   		Connection connection = null;		try {   						String url = "jdbc:mysql://localhost:3306/grade"					+ "?user=root&password=18170021&serverTimezone=UTC";			connection = DriverManager.getConnection(url);		}catch (SQLException e) {   			System.out.println("JDBC connection error");			e.printStackTrace();		}		return connection;	}	public static void closeConn(Statement stmt,Connection conn) {   		try{   			if(stmt!= null)				stmt.close();			if(conn!=null)				conn.close();		}catch(SQLException e){   			System.out.println("close error");			e.printStackTrace();		}	}	  //之后查询要用到ResultSet	public static void closeConn(ResultSet rs, Statement stmt, Connection conn){    		try{   			if(rs != null){   				rs.close();			}			if(stmt!= null)				stmt.close();			if(conn!=null)				conn.close();		}catch(SQLException e){   			System.out.println("close error");			e.printStackTrace();		}	}}

例：通用删除

package cn.edu.hbue.wmp;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.SQLException;public class GeneralJDBCUpdate {   	public static void main(String[] args) {   		// TODO Auto-generated method stub				String sql = "delete from student where id = ?";  //有个id占位符，之后要填充，也就是通过id确定删除		update(sql,11);      	}		//要传入sql语句和不确定的占位符	public static void update(String sql,Object ... args){   				Connection connection = null;		PreparedStatement ps = null;		//1.获取连接		connection = JDBCUtil.getConn();				try {   			//2.预编译sql语句			ps = connection.prepareStatement(sql);						//3.填充占位符			for(int i = 0;i < args.length;i++){   				ps.setObject(i + 1, args[i]);			}						//4.执行sql语句			ps.execute();		} catch (SQLException e) {   			// TODO Auto-generated catch block			e.printStackTrace();		}finally{   						//5.关闭资源			JDBCUtil.closeConn(ps,connection);					}		}}