Java面向对象练习-实现员工管理系统（MySQL数据库存储）
需求详见：需求内容
本次变更：
1新建DBConnection类，用于获取/关闭数据库连接
2新建SQL工具类，存放数据库增删改查方法
3Test.java修改存储方式，调用SQL工具类
第一步：建库建表
Mysql中新建数据库名为：“EmployeeManager”，在该数据库下新建一个员工表：Employee，建表SQL如下：
--创建表Employee
create table Employee
(
id varchar(50) primary key,
name varchar(50),
position varchar(50),
holiday int,
salary decimal(8,2));
--插入两条数据
insert into Employee(id,name,position,holiday,salary) values('1','张三','普通员工',3,6700.00);
insert into Employee(id,name,position,holiday,salary) values('2','李四','普通员工',3,6700.00);
第二部：引入数据库驱动包
原有项目中导入数据库的驱动Jar包。
Eclipse引入方式：右键项目-build path-Configure Build path 弹出的对话框选择Libraries选项卡，点击右方的add External jar 然后选择你的驱动包点击确定就行。
Maven引入方式：pom中添加如下依赖（以Mysql为例）：
mysql
mysql-connector-java
6.0.6
PS：仓库地址推荐https://mvnrepository.com/
第三步：创建数据库连接类
接下来项目中新增数据库连接类DBConnection.java，源码如下
注意：若Mysql版本为8.0以上，url后缀增加
“&useSSL=false&serverTimezone=UTC”
并将驱动包替换为8.0以上版本
package jingshenxiaohuo.com.test;
/**
* @program: testApplication
* @description:连接工具类
* @version: V1
**/
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class DBConnection {
private static Connection conn = null;
/*
* SQLServer:
* classname:com.microsoft.sqlserver.jdbc.SQLServerDriver
* url:jdbc:sqlserver://localhost:1433;DatabaseName=EmployeeManager;user=sa;password=123
* Oralce:
* classname:oracle.jdbc.driver.OracleDriver
* url:jdbc:oracle:thin:@localhost:1521:orcl
* Postgres:
* classname:org.postgresql.Driver
* url:jdbc:postgresql://localhost/myDB
*/
//使用MYSql
private static final String classname="com.mysql.Driver";
private static final String url="jdbc:mysql://localhost/EmployeeManager?user=root&password=Abc123++";
//获取连接
public static Connection getConnection(){
try {
Class.forName(classname);
conn = DriverManager.getConnection(url);
} catch (Exception e) {
System.out.println("连接异常，异常信息："+e.getMessage());
}
return conn;
}
//关闭连接
public static void close(){
try {
conn.close();
} catch (SQLException e) {
System.out.println("关闭失败，异常信息："+e.getMessage());
}
}
}
第四步：创建数据库操作类
接下来项目中新增数据库操作类DBOption.java，实现对员工数据的增删改查操作，源码如下
package jingshenxiaohuo.com.test;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
/**
* @program: testApplication
* @description:
* @version: V1
**/
public class DBOption {
//添加
public static boolean add(Employee employee){
boolean isSaved = false;
try {
Connection conn = DBConnection.getConnection();
//?为占位符
String sql = "insert into Employee(id,name,position,holiday,salary) values(?,?,?,?,?)";
PreparedStatement ps = null;
ps = conn.prepareStatement(sql);
//指sql中第一个？为ID
ps.setString(1, employee.ID+"");
ps.setString(2, employee.name);
ps.setString(3, employee.position);
ps.setInt(4, employee.holiday);
ps.setDouble(5, employee.salary);
isSaved = ps.execute();
ps.close();
conn.close();
} catch (Exception e) {
System.out.println("存储异常，异常原因："+e.getMessage());
}
return isSaved;
}
//修改
public static boolean update(Employee employee){
boolean isUpdate = false;
try {
Connection conn = DBConnection.getConnection();
//?为占位符
String sql = "update Employee set id=?,name=?,position=?,holiday=?,salary=? where name=?";
PreparedStatement ps = null;
ps = conn.prepareStatement(sql);
//指sql中第一个？为ID
ps.setString(1, employee.ID+"");
ps.setString(2, employee.name);
ps.setString(3, employee.position);
ps.setInt(4, employee.holiday);
ps.setDouble(5, employee.salary);
ps.setString(6, employee.name);
isUpdate = ps.execute();
ps.close();
conn.close();
} catch (Exception e) {
System.out.println("更新异常，异常原因："+e.getMessage());
}
return isUpdate;
}
//删除
public static boolean delete(String name){
boolean isDelete = false;
try {
Connection conn = DBConnection.getConnection();
//?为占位符
String sql = "delete from Employee where name=?";
PreparedStatement ps = null;
ps = conn.prepareStatement(sql);
//指sql中第一个？为ID
ps.setString(1, name);
isDelete = ps.execute();
ps.close();
conn.close();
} catch (Exception e) {
System.out.println("删除异常，异常原因："+e.getMessage());
}
return isDelete;
}
//查询
public static void query(){
try {
Connection conn = DBConnection.getConnection();
String sql = "select * from Employee";
PreparedStatement ps = conn.prepareStatement(sql);
ResultSet rs = ps.executeQuery();
while (rs.next()) {
System.out.println(rs.getString(1) + "\t" + rs.getString(2) + "\t" + rs.getString(3) + "\t\t" + rs.getString(4) + "\t" + rs.getString(5));
}
rs.close();
ps.close();
conn.close();
} catch (Exception e) {
System.out.println("查询异常，异常原因："+e.getMessage());
}
}
//查询单个人根据人名
public Employee selectEmployeeByName(String name){
Employee employee = null;
try {
Connection conn = DBConnection.getConnection();
String sql = "select * from Employee where name = '"+name+"'";
PreparedStatement ps = conn.prepareStatement(sql);
ResultSet rs = ps.executeQuery();
if(rs.next()) {
employee = new Employee(rs.getString(1), rs.getString(2), rs.getString(3), rs.getInt(4), rs.getDouble(5));
}
rs.close();
ps.close();
conn.close();
} catch (Exception e) {
System.out.println("查询异常，异常原因："+e.getMessage());
}
return employee;
}
}
最后，就是进入操作类TestEMD.java的编写了，代码如下：
package jingshenxiaohuo.com.test;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
/**
* @program: testApplication
* @description:
* @version: V1
**/
public class Test {
private static Scanner sc = new Scanner(System.in);
private static List em = new ArrayList();
//操作入口
public static void opt() {
System.out.println("---- 工资管理系统 ----");
System.out.println("-------------------------------");
System.out.println("--- 1 增加 ---");
System.out.println("--- 2 删除 ---");
System.out.println("--- 3 修改 ---");
System.out.println("--- 4 查询 ---");
System.out.println("--- 0 退出 ---");
System.out.println("-------------------------------");
System.out.println("请输入你要选择的操作：");
Scanner sc = new Scanner(System.in);
String s = sc.next();
switch (s) {
case "1":
addEmployee();
break;
case "2":
delEmployee();
break;
case "3":
updateEmployee();
break;
case "4":
queryEmployee();
break;
case "0":
System.out.println("谢谢使用");
break;
default:
System.out.println("指令错误请重新输入！");
opt();
break;
}
}
//新增员工
public static void addEmployee() {
System.out.println("------增加员工------");
System.out.println("请输入相关信息：");
System.out.print("ID：");
String id = sc.next();
System.out.print("姓名:");
String name = sc.next();
System.out.print("职务:");
String position = sc.next();
System.out.print("请假天数:");
int holiday = sc.nextInt();
System.out.print("基本工资:");
double salary = sc.nextInt();
Employee a = null;
switch (position) {
case "普通员工":
a = new CommonEmployee(id,name,position,holiday,salary);
break;
case "经理":
a = new Manager(id,name,position,holiday,salary);
break;
case "董事长":
a = new Director(id,name,position,holiday,salary);
break;
default:
System.out.println("不存在此职务，请重新输入！");
addEmployee();
break;
}
if (a != null) {
a.sumSalary();
em.add(a);
//数据库存储
DBOption.add(a);
System.out.println("添加成功！");
}
opt();
}
//删除员工
public static void delEmployee() {
System.out.println("----------删除员工---------");
System.out.println("请输入员工姓名：");
String n = sc.next();
for (int i = 0; i < em.size(); i++) {
if (em.get(i).name.equals(n)) {
System.out.println("你要删除的是：");
em.get(i).display();
System.out.println("你确定要删除吗？\n [Y]确定，[N]取消");
String s = sc.next();
if (s.toLowerCase().equals("y")) {
em.remove(i);
//删除员工
boolean isDeleted = DBOption.delete(n);
if(isDeleted){
System.out.println("删除成功！");
}
opt();
} else if (s.toLowerCase().equals("n")) {
opt();
} else {
System.out.println("输入指令不正确，请重新输入！");
delEmployee();
}
} else {
if (i != em.size() - 1) {
continue;
} else {
System.out.println("你输入的账号不存在！请重新输入！");
delEmployee();
}
}
}
}
//修改员工
public static void updateEmployee(){
System.out.println("--------------修改员工资料-------------");
System.out.println("请输入你要修改的姓名：");
String s = sc.next();
out: for (int i = 0; i < em.size(); i++) {
if (em.get(i).name.equals(s)) {
System.out.println("你要修改的是：");
em.get(i).display();
System.out.println("请重新输入相关信息：");
System.out.print("ID：");
String id = sc.next();
System.out.print("姓名:");
String name = sc.next();
System.out.print("职务:");
String position = sc.next();
System.out.print("请假天数:");
int holiday = sc.nextInt();
System.out.print("基本工资:");
double salary = sc.nextDouble();
if (em.get(i).position.equals(position)) {
em.get(i).ID = id;
em.get(i).name = name;
em.get(i).position = position;
em.get(i).holiday = holiday;
em.get(i).salary = salary;
em.get(i).sumSalary();
System.out.println("修改成功！");
em.get(i).display();
}else{
Employee a = null;
switch (position) {
case "普通员工":
a = new CommonEmployee(id,name,position,holiday,salary);
break;
case "经理":
a = new Manager(id,name,position,holiday,salary);
break;
case "董事长":
a = new Director(id,name,position,holiday,salary);
break;
default:
System.out.println("不存在此职务，请重新输入！");
addEmployee();
break;
}
if (a != null) {
a.sumSalary();
em.set(i, a);
DBOption.update(a);
}
}
opt();
} else {
if (i != em.size() - 1) {
continue out;
} else {
System.out.println("你输入的员工不存在！请重新输入！");
updateEmployee();
}
}
}
}
//查询员工
public static void queryEmployee() {
//查询所有并展示
DBOption.query();
//继续操作
opt();
}
public static void main(String[] args) {
Test.opt();
}
}
小伙看完记得给个