在Java编程中，如何使用不同的行方法来获取表中的行，更新表等？假定数据库名称是：testdb，其中有两张表:employee和dept，employee表中有4条记录,dept表中有2条记录。

创建数据库表的语句 -

use testdb;
-- 员工表
drop table if exists employees;
create table if not exists employees (
  id int not null primary key,
  age int not null,
  name varchar(64),
  dept_id int(10)
);
INSERT INTO employees VALUES (100, 28, 'MaxSu', 1);
INSERT INTO employees VALUES (101, 25, 'WeiWang', 2);
INSERT INTO employees VALUES (102, 30, 'KidaSu', 2);
INSERT INTO employees VALUES (103, 28, 'KobeBryant', 1);
----
-- 部门表
drop table if exists dept;
create table if not exists dept (
  id int not null primary key,
  name varchar (64)
);
INSERT INTO dept VALUES (1, '技术部');
INSERT INTO dept VALUES (2, '市场部');

以下示例使用ResultSet的first(), last(), deletRow(), getRow(), insertRow()方法来删除或插入ResultSet的行并移动指针到第一个或最后一个记录。

package com.yiibai;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

import java.sql.*;

public class UseRowMethods {
    public static void main(String[] args) throws Exception {
        String JDBC_DRIVER = "com.mysql.jdbc.Driver";
        String DB_URL = "jdbc:mysql://localhost/testdb?useSSL=false";
        String User = "root";
        String Passwd = "123456";
        try {
            Class.forName(JDBC_DRIVER);
        } catch (ClassNotFoundException e) {
            System.out.println("Class not found " + e);
        }
        Connection con = DriverManager.getConnection(DB_URL, User, Passwd);
        Statement stmt = con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);

        String query = "select * from employees";
        ResultSet rs = stmt.executeQuery(query);
        rs.last();
        System.out.println("No of rows in table = " + rs.getRow());

        rs.moveToInsertRow();
        rs.updateInt("id", 114);
        rs.updateString("name", "Suzend");
        rs.updateString("age", "26");
        rs.insertRow();

        System.out.println("Row added");
        rs.first();
        rs.deleteRow();
        System.out.println("first row deleted");
    }
}

上述代码示例将产生以下结果。

No of rows in table = 7
Row added
first row deleted

注：如果JDBC驱动程序安装不正确，将获得ClassNotfound异常。

Class not found java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
JDBC Class found
SQL exception occuredjava.sql.SQLException: No suitable driver found for jdbc:mysql://localhost/testdb

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