Javassm（Spring+SpringMVC+MyBatis）项目实例

Myth丶恋晨 2022-10-29 10:29 93阅读 0赞

# 一、项目介绍 #

> 使用了`SSM`（`Spring+SpringMVC+MyBatis`）框架，查询数据库中的数据并显示到页面上。末尾资料上有全部源码以供参考。效果如下：  
> ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2gxNTgzNTE2MTI1MA_size_16_color_FFFFFF_t_70]

# 二、项目准备 #

## 2.1 准备数据库 ##

CREATE DATABASE /*!32312 IF NOT EXISTS*/`ssm` /*!40100 DEFAULT CHARACTER SET utf8 */;
    
    USE `ssm`;
    
    DROP TABLE IF EXISTS `departments`;
    
    CREATE TABLE `departments` (
      `id` int(11) NOT NULL AUTO_INCREMENT,
      `name` varchar(100) NOT NULL,
      PRIMARY KEY (`id`)
    ) ENGINE=InnoDB AUTO_INCREMENT=7 DEFAULT CHARSET=utf8;
    
    insert  into `departments`(`id`,`name`) values 
    (1,'教学部'),
    (2,'教务部'),
    (3,'运营部'),
    (4,'咨询部'),
    (5,'就业部'),
    (6,'财务部');
    
    DROP TABLE IF EXISTS `employees`;
    
    CREATE TABLE `employees` (
      `id` int(11) NOT NULL AUTO_INCREMENT,
      `last_name` varchar(100) NOT NULL,
      `email` varchar(100) DEFAULT NULL,
      `gender` int(11) DEFAULT NULL,
      `dept_id` int(11) DEFAULT NULL,
      PRIMARY KEY (`id`),
      KEY `dept_id` (`dept_id`),
      CONSTRAINT `employees_ibfk_1` FOREIGN KEY (`dept_id`) REFERENCES `departments` (`id`)
    ) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8;
    
    insert  into `employees`(`id`,`last_name`,`email`,`gender`,`dept_id`) values 
    (1,'韩总','hanyanbing@atguigu.cn',1,1),
    (2,'马云','mayun@alibaba.com',1,2),
    (3,'马化腾','mahuateng@tencent.com',1,3);

## 2.2 创建`web`项目（自行准备） ##

## 2.3 准备`jar`包 ##

> 预览  
> ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2gxNTgzNTE2MTI1MA_size_16_color_FFFFFF_t_70 1]  
> 备注：有不理解的自行百度，都是必不可少的`jar`包

# 三、项目开始 #

## 3.1 总预览 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2gxNTgzNTE2MTI1MA_size_16_color_FFFFFF_t_70 2]

## 3.2 `web.xml`配置文件 ##

<servlet>
            <servlet-name>dispatcherServlet</servlet-name>
            <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
            <init-param>
                <param-name>contextConfigLocation</param-name>
                <param-value>classpath:springmvc.xml</param-value>
            </init-param>
            <load-on-startup>1</load-on-startup>
        </servlet>
        <servlet-mapping>
            <servlet-name>dispatcherServlet</servlet-name>
            <url-pattern>/</url-pattern>
        </servlet-mapping>
        
        <context-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:beans.xml</param-value>
        </context-param>
        
        
        <listener>
            <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
        </listener>

## 3.3 配置`SpringMVC`配置文件（`Springmvc.xml`） ##

<context:component-scan base-package="com.atguigu.ssm" use-default-filters="false">
    		
            <context:include-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
        </context:component-scan>
    
        
        <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="viewResolver">
        	
            <property name="prefix" value="/WEB-INF/views/"/>
            
            <property name="suffix" value=".jsp"/>
        </bean>
    
        <mvc:annotation-driven/>

> 备注：这里的`mvc`导入的是`xmlns:mvc="http://www.springframework.org/schema/mvc"`  
> 还会有一些后续的配置如处理静态资源等因为这个项目不需要所以不做配置

## 3.4 数据库`properties`文件 ##

#key=value
    jdbc.username=root
    jdbc.password=123456
    jdbc.url=jdbc:mysql://localhost:3306/ssm
    jdbc.driverClassName=com.mysql.jdbc.Driver
    
    jdbc.initialSize=5
    jdbc.maxActive=10

## 3.4 编写`Spring`配置文件（`Spring.xml`） ##

<context:component-scan base-package="com.atguigu.ssm">
            
            <context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
        </context:component-scan>
    
        
        <context:property-placeholder location="classpath:druid.properties"/>
    
        
        <bean id="druidDataSource" class="com.alibaba.druid.pool.DruidDataSource">
            <property name="username" value="${jdbc.username}"/>
            <property name="password" value="${jdbc.password}"/>
            <property name="url" value="${jdbc.url}"/>
            <property name="driverClassName" value="${jdbc.driverClassName}"/>
            <property name="initialSize" value="${jdbc.initialSize}"/>
            <property name="maxActive" value="${jdbc.maxActive}"/>
        </bean>
    
        
        <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
            <property name="dataSource" ref="druidDataSource"/>
        </bean>
    
        
        <tx:annotation-driven></tx:annotation-driven>
    
        
        
        <bean id="sqlSessionFactoryBean" class="org.mybatis.spring.SqlSessionFactoryBean">
            
            <property name="dataSource" ref="druidDataSource"></property>
            
            <property name="configLocation" value="classpath:mybatis-config.xml"></property>
            
            <property name="mapperLocations" value="classpath:com/atguigu/ssm/mapper/*.xml"></property>
            
        </bean>
    
        
        <mybatis-spring:scan base-package="com.atguigu.ssm.mapper"></mybatis-spring:scan>

> 备注：这里的`tx`导入的是`xmlns:tx="http://www.springframework.org/schema/tx"`

## 3.4 编写页面（`index.jsp`） ##

<%--写一个超链接--%>
    	<a href="${pageContext.request.contextPath}/getEmployee">获取所有员工</a>

## 3.5 编写请求（`EmployeeController.java`） ##

@Controller
    public class EmployeeController {
        
    
        @Autowired
        private EmployeeService employeeService;
    
        @RequestMapping(value = "/getEmployee",method = RequestMethod.GET)
        public String getEmployee(Map<String,Object> map){
        
            //调用EmployeeService中的获取员工的方法
            List<Employee> employees = employeeService.getEmployee();
            map.put("emps",employees);
            System.out.println(employees);
            return "list";
        }
    }

> 这里返回的是字符串，在`springmvc`视图解析器中已经配置过前缀和后缀了，他会自动生成路径。

## 3.6 编写跳转页面 ##

<center>
        <c:if test="${empty requestScope.emps}">
            <h1>没有任何员工</h1>
        </c:if>
        <c:if test="${not empty requestScope.emps}">
            <h1>员工信息</h1>
            <table border="1" cellpadding="10" cellspacing="0">
                <tr>
                    <th>Id</th>
                    <th>LastName</th>
                    <th>Email</th>
                    <th>Gender</th>
                    <th>Department</th>
                    <th colspan="2">操作</th>
                </tr>
                <c:forEach items="${requestScope.emps}" var="emp">
                    <tr>
                        <td>${emp.id}</td>
                        <td>${emp.lastName}</td>
                        <td>${emp.email}</td>
                        <td>
                            <c:if test="${emp.gender == 1}">
                                男
                            </c:if>
                            <c:if test="${emp.gender == 0}">
                                女
                            </c:if>
                        </td>
                        <td>${emp.department.departmentName}</td>
                        <td><a href="#">Edit</a> </td>
                        <td><a href="#">Delete</a></td>
                    </tr>
                </c:forEach>
            </table>
        </c:if>
        <br>
        <br>
        <a>添加新员工</a>
    </center>

> 备注：先引入`jstl`在开头写`<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>`

## 3.7 编写实体类（`Employee`，`Department`） ##

public class Department {
        
    
    	private Integer id;
    	private String departmentName;
    
    	···空参有参构造
    
    	···get、set方法
    
    	···toString方法
    }

public class Employee {
        
    
    	private Integer id;
    	private String lastName;
    	private String email;
    	private Integer gender;
    	
    	private Department department;
    	
    	···空参有参构造
    
    	···get、set方法
    
    	···toString方法

## 3.8 编写service（`EmployeeService.java`、`EmployeeServiceImpl.java`） ##

public interface EmployeeService {
        
    	//获取所有员工信息
        List<Employee> getEmployee();
    }

@Service
    public class EmployeeServiceImpl implements EmployeeService {
        
    
        @Autowired
        private EmployeeMapper employeeMapper;
    
        @Override
        public List<Employee> getEmployee() {
        
            //调用employeeMapper中获取所有员工的方法
            List<Employee> employees = employeeMapper.getEmployees();
            return employees;
        }
    }

## 3.9 编写`Mapper`（`MyBatis`的全局配置文件、`EmployeeMapper.java`、`EmployeeMapper.xml`） ##

<?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>
    
        
        <settings>
            
            <setting name="mapUnderscoreToCamelCase" value="true"/>
        </settings>
    
    </configuration>

public interface EmployeeMapper {
        
        List<Employee> getEmployees();
    }

<?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.atguigu.ssm.mapper.EmployeeMapper">
        <select id="getEmployees" resultMap="myEmp" >
            select e.*,d.id d_id,d.name d_name
            from employees e
            left join departments d
            on e.dept_id = d.id
        </select>
    
        
        <resultMap id="myEmp" type="com.atguigu.ssm.entities.Employee">
            
            <id column="id" property="id"></id>
    
            <result column="last_name" property="lastName"></result>
            <result column="email" property="email"></result>
            <result column="gender" property="gender"></result>
            <result column="last_name" property="lastName"></result>
    
            <association property="department" javaType="com.atguigu.ssm.entities.Department">
                
                <id column="d_id" property="id"></id>
                
                <result column="d_name" property="departmentName"></result>
            </association>
        </resultMap>
    </mapper>

## 3.10 总结 ##

> 到现在项目部分算是写完了开始配置Tomcat就可以运行了  
> 项目源代码参考[SSM（Spring+SpringMVC+MyBatis）项目实例][SSM_Spring_SpringMVC_MyBatis]

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[SSM_Spring_SpringMVC_MyBatis]: https://download.csdn.net/download/h15835161250/15242929