JAVA JDBC 增删改查简单例子

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);
        }
    }

}