java对mysql增删查改_Java实现对mysql数据库的增删查改

前面我们已经讲过如何实现对mysql数据库的连接。最简单的数据库操作就是增删查改。

其实对懂得实现对数据库的连接，其余的，对于一些简单的操作都是很简单的。

查看数据

public static void show_info() throws ClassNotFoundException, SQLException{

sql = "select * from stu_info";

Connection con = connect();

Statement st = con.createStatement();

ResultSet rs = st.executeQuery(sql);

System.out.println("学号\t姓名\t出生日期 \t性别\t课程号");

while(rs.next()){

System.out.println(rs.getString(1)+"\t"+rs.getString(2)+"\t"+rs.getString(3)+"\t"+rs.getString(4)+"\t"+rs.getString(5));

}

con.close();

}

添加数据

public static void insert() throws ClassNotFoundException, SQLException{

Connection con = connect();

System.out.println("请输入数据：");

Scanner input = new Scanner(System.in);

int sID = input.nextInt();

String sName = input.next();

String brithday = input.next();

String sex = input.next();

String s_cid = input.next();

Statement st = con.createStatement();

sql = "insert into stu_info values(?,?,?,?,?)";

PreparedStatement pre = (PreparedStatement) con.prepareStatement(sql);

pre.setInt(1, sID);

pre.setString(2, sName);

pre.setString(3, brithday);

pre.setString(4, sex);

pre.setString(5, s_cid);

int count = pre.executeUpdate();

System.out.println(count+"条数据发生了变化");

pre.close();

con.close();

}

修改数据

public static void modify() throws ClassNotFoundException, SQLException{

Connection con = connect();

Scanner input = new Scanner(System.in);

System.out.println("输入修改的学号");

int sID = input.nextInt();

System.out.println("输入修改信息");

String sName = input.next();

String brithday = input.next();

String sex = input.next();

String s_cid = input.next();

sql ="update stu_info set sName = ?,birthday = ?,sex = ? ,s_cid = ? where sID = " +sID;

PreparedStatement pre = (PreparedStatement) con.prepareStatement(sql);

pre.setString(1, sName);

pre.setString(2, brithday);

pre.setString(3, sex);

pre.setString(4, s_cid);

int count = pre.executeUpdate();

System.out.println(count+"条数据发生变化");

pre.close();

con.close();

}

删除数据

public static void delete() throws ClassNotFoundException, SQLException{

Connection con = connect();

System.out.println("输入删除的学号");

Scanner input = new Scanner(System.in);

int sID = input.nextInt();

sql = "delete from stu_info where sID = " +sID;

Statement st = con.createStatement();

int count = st.executeUpdate(sql);

System.out.println(count+"条数据发生了变化");

con.close();

}

这里出现了两个不同的类Statement 和PrepardStatement。其中PrepardStatement是由Statement继承过来的。

PrepardStatement提高了代码的可读性和维护性