JDBC复习

青旅半醒 2021-07-25 01:29 392阅读 0赞

**目录**

什么是JDBC

图解

需要的jar包

新建一个数据库

导入数据库依赖

JDBC固定步骤

实战1

实战2

--------------------

# 什么是JDBC #

Java database Connection：Java数据库连接

# 图解 #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70][]

# 需要的jar包 #

1 java.sql

2 javax.sql

3 mysql-connector-java:连接驱动

# 新建一个数据库 #

CREATE TABLE `users` (
      `id` int(11) NOT NULL,
      `name` varchar(50) DEFAULT NULL,
      `password` varchar(40) DEFAULT NULL,
      `email` varchar(50) DEFAULT NULL,
      `birthday` date DEFAULT NULL,
      PRIMARY KEY (`id`)
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
    INSERT INTO users (id,name,password,email,birthday)VALUES(1,'张三','123456','cakin@qq.com','2020-01-01');

# 导入数据库依赖 #

<dependencies>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.46</version>
        </dependency>
    </dependencies>

IDEA连接数据源

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70 1][]

# JDBC固定步骤 #

1 加载驱动

2 连接数据库

3 向数据库发送SQL的对象Statement：CRUD

4 编写SQL

5 执行SQL

6 关闭连接

# 实战1 #

package com.cakin;
    
    
    import java.sql.*;
    
    
    /**
    * @ClassName: JdbcTest
    * @Description: Jdbc测试
    * @Date: 2020/6/18
    * @Author: cakin
    */
    public class JdbcTest {
        public static void main(String[] args) throws ClassNotFoundException, SQLException {
            // useUnicode=true&characterEncoding=utf8 解决中文乱码
            String url = "jdbc:mysql://localhost:3306/jdbc?useUnicode=true&characterEncoding=utf8";
            String username = "root";
            String password = "123456";
    
    
            // 1 加载驱动
            Class.forName("com.mysql.jdbc.Driver");
            // 2 获得连接对象
            Connection connection = DriverManager.getConnection(url, username, password);
            // 3 获得发送SQL对象statement，可以进行增删查改操作
            Statement statement = connection.createStatement();
            // 4 编写SQL
            String sql = "select * from users";
            // 5 执行SQL
            ResultSet rs = statement.executeQuery(sql);
    
    
            while (rs.next()) {
                System.out.println("id=" + rs.getObject("id"));
                System.out.println("name=" + rs.getObject("name"));
                System.out.println("password=" + rs.getObject("password"));
                System.out.println("email=" + rs.getObject("email"));
            }
            // 6 关闭资源
            rs.close();
            statement.close();
            connection.close();
        }
    }

# 实战2 #

package com.cakin;
    
    
    import java.sql.*;
    
    
    /**
    * @ClassName: JdbcTest2
    * @Description: jdbc测试
    * @Date: 2020/6/18
    * @Author: cakin
    */
    public class JdbcTest2 {
        public static void main(String[] args) throws ClassNotFoundException, SQLException {
            // useUnicode=true&characterEncoding=utf8 解决中文乱码
            String url = "jdbc:mysql://localhost:3306/jdbc?useUnicode=true&characterEncoding=utf8";
            String username = "root";
            String password = "123456";
    
    
            // 1 加载驱动
            Class.forName("com.mysql.jdbc.Driver");
            // 2 获得连接对象
            Connection connection = DriverManager.getConnection(url, username, password);
            // 3 编写SQL
            String sql = "insert into users(`id`, `name`, `password`, `email`, `birthday`) values (?,?,?,?,?)";
            // 4 预编译
            PreparedStatement preparedStatement = connection.prepareStatement(sql);
            preparedStatement.setInt(1, 8);
            preparedStatement.setString(2, "cakin");
            preparedStatement.setString(3, "123456");
            preparedStatement.setString(4, "cakin@qq.com");
            preparedStatement.setDate(5, new Date(new java.util.Date().getTime()));
            // 5 执行
            preparedStatement.executeUpdate();
    
    
            // 6 关闭资源
            connection.close();
        }
    }

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