时间:2021-07-01 10:21:17 帮助过:23人阅读
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本模板非常适用于正在学习计算机专业的大学生,在做课程设计时,难免会遇到需要使用到数据库的情况。这里强烈推荐使用MySQL数据库,为什么呢?简单说,社会上大部分的大中小型网络公司都在使用MySQL,成本低是一个很大的原因!
本模板主要是对MySQL数据库进行增删改查操作
主要版本号:
mysql-connector-java-8.0.19
- package com;
- ?
- import java.sql.Connection;
- import java.sql.DriverManager;
- import java.sql.Statement;
- ?
- public class Insert {
- public static void main(String[] args) throws Exception {
- Class.forName("com.mysql.cj.jdbc.Driver"); //抛出异常,写法是固定的
- String url = "jdbc:mysql://localhost:3306/class?useUnicode=true&characterEncoding=utf8&useSSL=true&serverTimezone=UTC";
- String username = "root"; //数据库账户名
- String password = "123456"; //数据库登录密码
- Connection connection = DriverManager.getConnection(url, username, password);
- Statement statement = connection.createStatement(); //statement来执行sql的对象
- String sql = "INSERT INTO `student`(`name`,`pwd`,`sex`,`birthday`,`address`,`email`,`gradeid`)\n" +
- "VALUES(‘yfl‘,‘9933‘,‘女‘,‘1999-02-13‘,‘xiapu‘,‘102065@qq‘,‘2‘)";
- int num = statement.executeUpdate(sql); //执行完sql后返回受影响的行数
- if(num>0)
- System.out.println("插入成功!");
- statement.close();
- connection.close();
- }
- }
- ?
- package com;
- ?
- import java.sql.Connection;
- import java.sql.DriverManager;
- import java.sql.Statement;
- ?
- public class Delete {
- public static void main(String[] args) throws Exception {
- Class.forName("com.mysql.cj.jdbc.Driver");
- String url = "jdbc:mysql://localhost:3306/class?useUnicode=true&characterEncoding=utf8&useSSL=true&serverTimezone=UTC";
- String username = "root"; //数据库账户名
- String password = "123456"; //数据库登录密码
- Connection connection = DriverManager.getConnection(url, username, password);
- Statement statement = connection.createStatement(); //statement来执行sql的对象
- String sql = "DELETE FROM `student` WHERE id=5";
- int num = statement.executeUpdate(sql); //执行完sql后返回受影响的行数
- if(num>0)
- System.out.println("删除成功!");
- statement.close();
- connection.close();
- }
- }
- <span><span class="cm-keyword"><span class="cm-def"><span><span><span><span class="cm-keyword"><span class="cm-variable"><span class="cm-variable"><span class="cm-variable"><span><span class="cm-keyword"><span class="cm-variable"><span class="cm-variable"><span class="cm-variable"><span><span class="cm-keyword"><span class="cm-variable"><span class="cm-variable"><span class="cm-variable"><span><span><span><span class="cm-keyword"><span class="cm-keyword"><span class="cm-def"><span><span class="cm-keyword"><span class="cm-keyword"><span class="cm-variable-3"><span class="cm-variable"><span class="cm-variable-3"><span class="cm-variable"><span class="cm-keyword"><span class="cm-variable"><span><span class="cm-variable"><span class="cm-variable"><span class="cm-string"><span><span class="cm-variable-3"><span class="cm-variable"><span class="cm-operator"><span class="cm-string"><span><span class="cm-variable-3"><span class="cm-variable"><span class="cm-operator"><span class="cm-string"><span class="cm-comment"><span><span class="cm-variable-3"><span class="cm-variable"><span class="cm-operator"><span class="cm-string"><span class="cm-comment"><span><span class="cm-variable"><span class="cm-variable"><span class="cm-operator"><span class="cm-variable"><span class="cm-variable"><span class="cm-variable"><span class="cm-variable"><span class="cm-variable"><span><span class="cm-variable"><span class="cm-variable"><span class="cm-operator"><span class="cm-variable"><span class="cm-variable"><span class="cm-comment"><span><span class="cm-variable-3"><span class="cm-variable"><span class="cm-operator"><span class="cm-string"><span><span class="cm-variable-3"><span class="cm-variable"><span class="cm-operator"><span class="cm-variable"><span class="cm-variable"><span class="cm-variable"><span class="cm-comment"><span><span class="cm-keyword"><span class="cm-variable"><span class="cm-operator"><span class="cm-number"><span><span class="cm-variable"><span class="cm-variable"><span class="cm-variable"><span class="cm-string"><span><span class="cm-variable"><span class="cm-variable"><span><span class="cm-variable"><span class="cm-variable"><span><span><br><span><span>?</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>
- package com;
- ?
- import java.sql.Connection;
- import java.sql.DriverManager;
- import java.sql.Statement;
- ?
- public class Update {
- public static void main(String[] args) throws Exception {
- Class.forName("com.mysql.cj.jdbc.Driver"); //抛出异常,写法是固定的
- String url = "jdbc:mysql://localhost:3306/class?useUnicode=true&characterEncoding=utf8&useSSL=true&serverTimezone=UTC";
- String username = "root"; //数据库账户名
- String password = "123456"; //数据库登录密码
- Connection connection = DriverManager.getConnection(url, username, password);//需要抛出异常,"connection"就可以代表数据库了
- Statement statement = connection.createStatement(); //statement来执行sql的对象
- String sql = "UPDATE `student` SET `name`=‘atm‘ WHERE `id`=3";
- int num = statement.executeUpdate(sql); //执行完sql后返回受影响的行数
- if(num>0)
- System.out.println("更新成功!");
- statement.close();
- connection.close();
- }
- }
- package com;
- ?
- import java.sql.*;
- ?
- public class Select {
- public static void main(String[] args) throws ClassNotFoundException, SQLException {
- //第一步:加载驱动
- Class.forName("com.mysql.cj.jdbc.Driver"); //抛出异常,写法是固定的
- //第二步:验证用户信息和url
- String url = "jdbc:mysql://localhost:3306/class?useUnicode=true&characterEncoding=utf8&useSSL=true&serverTimezone=UTC";
- String username = "root"; //数据库账户名
- String password = "123456"; //数据库登录密码
- //第三步:连接成功后获得数据库对象
- Connection connection = DriverManager.getConnection(url, username, password);//需要抛出异常,"connection"就可以代表数据库了
- //第四步:获取执行sql的对象
- Statement statement = connection.createStatement(); //statement来执行sql的对象
- //第五步:使用sql的对象去执行sql语句
- String sql = "SELECT * FROM `student`";
- ResultSet resultSet = statement.executeQuery(sql); //执行完sql后返回一个结果集resultSet,这个结果集已经封装了全部查询出来的结果
- /*
- statement.executeQuery();//查询操作,返回ResultSet
- statement.execute();//可以执行任何SQL
- statement.executeUpdate();//更新、插入、删除都用它,返回一个受影响的行数(int)
- */
- while (resultSet.next()){ //对结果进行打印
- System.out.println("id="+resultSet.getObject("id"));
- System.out.println("name="+resultSet.getObject("name"));
- }
- //第六步:使用完毕,释放数据库的连接
- resultSet.close();
- statement.close();
- connection.close();
- //释放连接尽量遵循先创建后释放的原则
- }
- }
事实上,这样的模板更适用于操作量小的工程项目,不利于代码的整洁化,接下来小编将会把这些代码进行封装,在使用时只需要调用封装的接口即可。
Java操作MySQL数据库模板
标签:fence div date() 释放 cti password root lock 小型