【JavaEE案例】员工管理系统

拼搏现实的明天。 2024-03-25 09:40 100阅读 0赞

**【案例介绍】**

<table style="width:500px;"> 
 <tbody> 
  <tr> 
   <td>员工编号（id）</td> 
   <td>员工名称（name）</td> 
   <td>员工年龄（age）</td> 
   <td>员工职位（position）</td> 
  </tr> 
  <tr> 
   <td>1</td> 
   <td>张三</td> 
   <td>20</td> 
   <td>员工</td> 
  </tr> 
  <tr> 
   <td>2</td> 
   <td>李四</td> 
   <td>18</td> 
   <td>员工</td> 
  </tr> 
  <tr> 
   <td>3</td> 
   <td>王五</td> 
   <td>35</td> 
   <td>经理</td> 
  </tr> 
 </tbody> 
</table>

现有一员工表，要求根据员工表在数据库中创建一个employee表，根据所学知识完成一个员工管理系统，该系统需要实现以下几个功能。

（1）根据id查询员工信息。

（2）新增员工信息。

（3）根据id修改员工信息。

（4）根据id删除员工信息。

**【案例实现】**

![8931a59888074d6991269a8c4c5e2ebf.png][]

**1.数据准备：**在MySQL中创建一个名称为mybatis的数据库

CREATE DATABASE mybatis;

在数据库中创建employee表

CREATE TABLE employee(
    	id int primary key auto_increment,
    	name varchar(20) not null,
    	age int not null,
    	position varchar(20)
    );

并插入3条数据

INSERT INTO employee(id,name,age,position) VALUES(null,'张三',20,'员工'),(null,'李四',18,'员工'),(null,'王五',35,'经理');

**2.引入相关依赖：**在项目的pom.xml文件中导入MySQL驱动包、JUnit测试包、MyBatis的核心包等相关依赖。

<?xml version="1.0" encoding="UTF-8"?>
    <project xmlns="http://maven.apache.org/POM/4.0.0"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
     
        <groupId>org.xinhua</groupId>
        <artifactId>MyBatisTest</artifactId>
        <version>1.0-SNAPSHOT</version>
     
        <properties>
            <maven.compiler.source>17</maven.compiler.source>
            <maven.compiler.target>17</maven.compiler.target>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        </properties>
     
        <dependencies>
            <dependency>
                <groupId>org.mybatis</groupId>
                <artifactId>mybatis</artifactId>
                <version>3.5.11</version>
            </dependency>
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>8.0.28</version>
            </dependency>
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>4.12</version>
                <scope>compile</scope>
            </dependency>
        </dependencies>
        <build>
            <resources>
                <resource>
                    <directory>src/main/java</directory>
                    <includes>
                        <include>**/*.properties</include>
                        <include>**/*.xml</include>
                    </includes>
                    <filtering>true</filtering>
                </resource>
            </resources>
        </build>
     
    </project>

**3.POJO类准备：**创建持久化类Employee，并在类中声明id（编号）、name（姓名）、age（年龄）和position（职位）属性，以及属性对应的getter/setter方法。

package com.itheima.pojo;
    
    public class Employee {
        private Integer id;
        private String name;
        private Integer age;
        private String position;
    
        public void setId(Integer id)
        {
            this.id = id;
        }
        public void setName(String name)
        {
            this.name = name;
        }
        public void setAge(Integer age)
        {
            this.age = age;
        }
        public void setPosition(String position)
        {
            this.position = position;
        }
    
        public Integer getId()
        {
            return id;
        }
        public String getName()
        {
            return name;
        }
        public Integer getAge()
        {
            return age;
        }
        public String getPosition()
        {
            return position;
        }
    
        @Override
        public String toString() {
            return "Employee{"+"id="+id+",name="+name+",age="+age+",position="+position+"}";
        }
    }

**4.创建映射文件EmployeeMapper.xml：**该文件主要用于配置SQL语句和Java对象之间的映射 。

<?xml version="1.0" encoding="UTF-8" ?>
    <!DOCTYPE mapper
            PUBLIC "-//mybatis.org//DTD mapper 3.0//EN"
            "http://myBatis.org/dtd/mybatis-3-mapper.dtd">
    
    <mapper namespace="com.itheima.mapper.EmployeeMapper">
    
        
        <select id="select01" parameterType="Integer"
                resultType="com.itheima.pojo.Employee">
            select * from employee where id = #{id}
        </select>
    
        
        <insert id="insert02" parameterType="com.itheima.pojo.Employee">
            insert into employee(id,name,age,position)values (#{id},#{name},#{age},#{position})
        </insert>
    
        
        <update id="update03" parameterType="com.itheima.pojo.Employee">
            update employee set name= #{name},age = #{age},position= #{position} where id = #{id}
        </update>
    
        
        <delete id="delete04" parameterType="Integer">
            delete from employee where id=#{id}
        </delete>
    </mapper>

**5.创建数据库连接信息配置文件db.properties：**在该文件中配置数据库连接的参数。

mysql.driver=com.mysql.cj.jdbc.Driver
    mysql.url=jdbc:mysql://localhost:3306/mybatis?serverTimezone=UTC&\
      characterEncoding=utf8&useUnicode=true&useSSL=false
    mysql.username=root
    mysql.password=root

**6.创建MyBatis的核心配置文件mybatis-config.xml：**该文件主要用于项目的环境配置。

<?xml version="1.0" encoding="UTF-8" ?>
    <!DOCTYPE configuration
            PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
            "http://mybatis.org/dtd/mybatis-3-config.dtd">
    <configuration>
        
        
        <properties resource="db.properties"/>
        <environments default="development">
            <environment id="development">
                <transactionManager type="JDBC"/>
                
                <dataSource type="POOLED">
                    <property name="driver" value="${mysql.driver}"/>
                    <property name="url" value="${mysql.url}"/>
                    <property name="username" value="${mysql.username}"/>
                    <property name="password" value="${mysql.password}"/>
                </dataSource>
            </environment>
        </environments>
    
        
        <mappers>
            <mapper resource="mappers/EmployeeMapper.xml"/>
        </mappers>
    
    </configuration>

**7.编写MyBatisUtils工具类：**该类用于封装读取配置文件信息的代码。

package com.itheima.Utils;
    
    import java.io.Reader;
    import org.apache.ibatis.io.Resources;
    import org.apache.ibatis.session.SqlSession;
    import org.apache.ibatis.session.SqlSessionFactory;
    import org.apache.ibatis.session.SqlSessionFactoryBuilder;
    
    public class MyBatisUtils {
        private static SqlSessionFactory sqlSessionFactory = null;
        //初始化SQLSessionFactory类加载MyBatis的配置文件
        static {
            try {
                //使用MyBatis提供的Resources类加载MyBatis的配置文件
                Reader reader = Resources.getResourceAsReader("mybatis-config.xml");
                //构建SqlSessionFactory工厂
                sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
            }catch(Exception e){
                e.printStackTrace();
            }
        }
        public static SqlSession getSession(){
            //获取SqlSession对象的静态方法
            return sqlSessionFactory.openSession(true);
            //若传入true表示关闭事务控制，自动提交;false表示开启事务控制
        }
    }

**8.编写测试类**

package com.itheima;
    import com.itheima.pojo.Employee;
    import com.itheima.Utils.MyBatisUtils;
    import org.apache.ibatis.session.SqlSession;
    import org.junit.Test;
    
    public class MyBatisTest {
        //(1)根据id查询员工信息
        @Test
        public void select01() {
            //通过工具类获取SQLSession对象
            SqlSession sqlSession = MyBatisUtils.getSession();
            //创建Employee对象接收SQL语句的查询结果
            Employee employee01 = sqlSession.selectOne("select01",2);
            System.out.println(employee01);
            //关闭事务
            sqlSession.close();
        }
        //(2)新增员工信息
        @Test
        public void insert02() {
            SqlSession sqlSession = MyBatisUtils.getSession();
            //实例化Employee
            Employee employee = new Employee();
            employee.setId(4);
            employee.setName("赵六");
            employee.setAge(100);
            employee.setPosition("老板");
            //这里的insertID一定要与EmployeeMapper文件中的id对应，要一模一样
            sqlSession.insert("insert02",employee);
            System.out.println("添加成功！");
            sqlSession.close();
        }
        //(3)根据id修改员工信息
        @Test
        public void update03() {
            SqlSession sqlSession = MyBatisUtils.getSession();
            Employee employee = new Employee();
            employee.setId(3);
            employee.setName("陈二");
            employee.setAge(40);
            employee.setPosition("经理");
            sqlSession.insert("update03",employee);
            System.out.println("更新成功！");
            sqlSession.close();
        }
        //(4)根据id删除员工信息
        @Test
        public void delete04() {
            SqlSession sqlSession = MyBatisUtils.getSession();
            sqlSession.delete("delete04", 1);
            System.out.println("删除成功！");
            sqlSession.close();
        }
    }

**9.运行结果**

![051bfd081dc049caa5f2942439219c23.png][]

[8931a59888074d6991269a8c4c5e2ebf.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/25/b652d6dd7b014558b20ce3ae52dda8a0.png
[051bfd081dc049caa5f2942439219c23.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/25/83e9f1bfeeec404dafd5a634616feb23.png