JDBC程序

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代码

package com.micro.profession.jdbc.practice;

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

public class HelloJDBC {
    static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
    static final String DB_URL = "jdbc:mysql://localhost/cloud_study";
    static final String USER = "root";
    static final String PASSWORD = "123456";

    public static void helloword() throws ClassNotFoundException {
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;

        // 1.装载驱动程序
        Class.forName(JDBC_DRIVER);
        // 2.建立数据库连接
        try {
            conn = DriverManager.getConnection(DB_URL, USER, PASSWORD);
            // 3.执行SQL语句
            stmt = conn.createStatement();
            rs = stmt.executeQuery("select userName from user");
            // 4.获取执行结果
            while (rs.next()) {
                System.out.println("Hello " + rs.getString("userName"));
            }
        } catch (SQLException e) {
            // 异常处理
            e.printStackTrace();
        } finally {
            // 5.清理环境
            try {
                if (conn != null)
                    conn.close();
                if (stmt != null)
                    stmt.close();
                if (rs != null)
                    rs.close();
            } catch (SQLException e) {
                // ignore
            }
        }

    }

    public static void main(String[] args) throws ClassNotFoundException {
        helloword();
    }

}

jdbc驱动使用Maven

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.18</version>
</dependency>

cmd使用mysql

mysql -u root -p