JDBC-查询功能

 创建 HumanResourceApp 主类

package hr;

import hr.command.Command;
import hr.command.QueryCommand;

import java.util.Scanner;

public class HumanResourceApp {
    public static void main(String[] args) {
        System.out.println("1-查询部门员工");
        Scanner in = new Scanner(System.in);
        Integer cmd = in.nextInt();
        switch (cmd) {
            case 1:
                Command command = new QueryCommand();
                command.execute();
                break;
        }
    }
}

创建 Command 接口

package hr.command;

public interface Command {
    public void execute();
}

创建 QueryCommand 类 

package hr.command;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.Scanner;

public class QueryCommand implements Command {
    @Override
    public void execute() {

        System.out.print("请输入部门名称：");
        Scanner in = new Scanner(System.in);
        String pdname = in.next();

        Connection conn = null;

        try {
            //1. 加载并注册JDBC驱动
            Class.forName("com.mysql.cj.jdbc.Driver");

            //2. 创建数据库连接
            conn = DriverManager.getConnection(
                    "jdbc:mysql://localhost:3306/zang?useSSL=false&useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai",
                    "root", "password"
            );

            //3. 创建Statement对象
            Statement stmt = conn.createStatement();
            ResultSet rs = stmt.executeQuery("select * from employee where dname='" + pdname + "'");

            //4. 遍历查询结果
            while (rs.next()) {
                Integer eno = rs.getInt(1); //eno
                String ename = rs.getString("ename");
                Float salary = rs.getFloat("salary");
                String dname = rs.getString("dname");
                System.out.println(dname + "-" + eno + "-" + ename + "-" + salary);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            //5. 关闭连接,释放资源
            try {
                if (conn != null && conn.isClosed() == false) {
                    conn.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
}