mysql数据库实现CURD操作

package jdbc_mysql.statement;

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 testStatementResultSet {

@Test

public void testDQL(){

Connection conn = null;

Statement stmt = null;

ResultSet rs = null;

try {

Class.forName("com.mysql.jdbc.Driver");

String url =
"jdbc:mysql://localhost:3306/school";

String user =
"root";

String
password = "root";

try {

conn
= DriverManager.getConnection(url, user, password);

stmt
= conn.createStatement();

String
sql = "select id,name,math from student";//可更改sql执行语句

rs
= stmt.executeQuery(sql);

//使用ResultSet

while(rs.next()){

//通过下标取数据

int
id = rs.getInt(0);

String
name = rs.getString(1);

int
math = rs.getInt(2);

System.out.println(id+name+math);

//通过字段名取数据

id=rs.getInt("id");

name
= rs.getString("name");

math
= rs.getInt("math");

System.out.println("###"+id+name+math);

}

} catch
(SQLException e) {

//
TODO Auto-generated catch block

e.printStackTrace();

}

} catch (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();

}

rs
= null;

}

if(stmt!=null){

try
{

stmt.close();

}
catch (SQLException e) {

//
TODO Auto-generated catch block

e.printStackTrace();

}

stmt
= null;

}

if(conn!=null){

try
{

conn.close();

}
catch (SQLException e) {

//
TODO Auto-generated catch block

e.printStackTrace();

}

//conn=null;

}

}

}

}