1、数据库配置文件jdbc.properties

driver=com.mysql.jdbc.Driver

url=jdbc:mysql://localhost:3306/test

username=root

password=

2、数据库数据类JdbcUtils

package com.test;

import java.io.IOException;

import java.io.InputStream;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.util.Properties;

public class JdbcUtils {

private static String driver = null;

    private static String url = null;

    private static String username = null;

    private static String password = null;

    // 加载驱动，获取数据库连接信息

    static {

        try {

            // 加载配置文件

            InputStream in = JdbcUtils.class.getClassLoader().getResourceAsStream("DB.properties");

            Properties properties = new Properties();

            properties.load(in);

            driver = properties.getProperty("driver");

            url = properties.getProperty("url");

            username = properties.getProperty("username");

            password = properties.getProperty("password");

            // 加载驱动

            Class.forName(driver);

        } catch (IOException e) {

            e.printStackTrace();

        } catch (ClassNotFoundException e) {

            e.printStackTrace();

        }

    }

    /**

     * 获取数据库连接

     * @throws SQLException

     */

    public static Connection getConnection() {

        try {

            return DriverManager.getConnection(url, username, password);

        } catch (SQLException e) {

            e.printStackTrace();

        }

        return null;

    }

    /**

     * 释放资源

     * @param connection

     * @param preparedStatement

     * @param resultSet

     */

    public static void releaseDB(Connection connection, PreparedStatement preparedStatement, ResultSet resultSet) {

        if (connection != null) {

            try {

                connection.close();

            } catch (SQLException e) {

                e.printStackTrace();

            }

        }

        if (preparedStatement != null) {

            try {

                preparedStatement.close();

            } catch (SQLException e) {

                e.printStackTrace();

            }

        }

        if (resultSet != null) {

            try {

                resultSet.close();

            } catch (SQLException e) {

                e.printStackTrace();

            }

        }

    }

}

3、增删改查

package com.test;

import java.sql.Connection;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

public class JdbcTest {

public void insert() {

Connection connection = null;

PreparedStatement preparedStatement = null;

try {

// 获取连接

connection = JdbcUtils.getConnection();

// 准备sql语句

String sql = "INSERT INTO user(id,name,age) VALUES(?,?,?)";

// 获取PrepareStatement对象

preparedStatement = connection.prepareStatement(sql);

// 填充占位符

preparedStatement.setInt(1, 6);

preparedStatement.setString(2, "小A");

preparedStatement.setInt(3, 25);

// 执行sql

int num = preparedStatement.executeUpdate();// 返回影响到的行数

System.out.println("一共影响到" + num + "行");

} catch (SQLException e) {

e.printStackTrace();

} finally {

JdbcUtils.releaseDB(connection, preparedStatement, null);

}

}

public void update() {

Connection connection = null;

PreparedStatement preparedStatement = null;

try {

// 获取连接

connection = JdbcUtils.getConnection();

// 准备sql语句

String sql = "update user set age = ? where name = ?";

// 获取PrepareStatement对象

preparedStatement = connection.prepareStatement(sql);

// 填充占位符

preparedStatement.setInt(1, 30);

preparedStatement.setString(2, "小A");

// 执行sql

int num = preparedStatement.executeUpdate();// 返回影响到的行数

System.out.println("一共影响到" + num + "行");

} catch (SQLException e) {

e.printStackTrace();

} finally {

JdbcUtils.releaseDB(connection, preparedStatement, null);

}

}

public void query() {

        Connection connection = null;

        PreparedStatement preparedStatement = null;

        ResultSet resultSet = null;

        try {

            connection = JdbcUtils.getConnection();

            String sql = "SELECT name,age FROM user";

            preparedStatement = connection.prepareStatement(sql);

            resultSet = preparedStatement.executeQuery();

            // 遍历结果集

            while (resultSet.next()) {

                String name = resultSet.getString(1);

                Integer age = resultSet.getInt(2);                

                System.out.println("name:" + name + ", age:" + age);

            }

        } catch (Exception e) {

        e.printStackTrace();

        } finally {

            JdbcUtils.releaseDB(connection, preparedStatement, resultSet);

        }

    }

public void delete() {

        Connection connection = null;

        PreparedStatement preparedStatement = null;

        try {

            connection = JdbcUtils.getConnection();

            String sql = "DELETE FROM user WHERE id = ?";

            preparedStatement = connection.prepareStatement(sql);

            preparedStatement.setInt(1, 6);

            int num = preparedStatement.executeUpdate();

            System.out.println("一共影响到" + num + "行");

        } catch (Exception e) {

        e.printStackTrace();

        } finally {

            JdbcUtils.releaseDB(connection, preparedStatement, null);

        }

    }

}

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