Spring+SpringMVC+MyBatisPlus详解

前言：学习过程中了解到MyBatis-Plus 功能非常强大，于是乎学了起来，结合已有框架进行整合，但是发现好多博客都是与SpringBoot进行整合的。所以总结一个与spring+SpringMVC整合详细笔记供大家参考。后续也会总结一个与springBoot的整合，毕竟SpringBoot更为主流。

第一步：搭建Maven架构、完善项目结构。

第二步：在文件中导入所需要的依赖

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="/POM/4.0.0" xmlns:xsi="http:///2001/XMLSchema-instance"
  xsi:schemaLocation="/POM/4.0.0 /xsd/maven-4.0.">
  <modelVersion>4.0.0</modelVersion>

  <groupId></groupId>
  <artifactId>ssmp</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <properties>
    <>UTF-8</>
  </properties>

  <dependencies>
    <!-- Apache工具组件 -->
    <dependency>
      <groupId></groupId>
      <artifactId>commons-lang3</artifactId>
      <version>3.10</version>
    </dependency>

    <!--mybatis-plus-->
    <dependency>
      <groupId></groupId>
      <artifactId>mybatis-plus</artifactId>
      <version>3.3.2</version>
    </dependency>

    <!--mysql驱动包-->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.38</version>
    </dependency>

    <!--spring-->
    <dependency>
      <groupId></groupId>
      <artifactId>spring-context</artifactId>
      <version>5.2.</version>
    </dependency>

    <dependency>
      <groupId></groupId>
      <artifactId>spring-orm</artifactId>
      <version>5.2.</version>
    </dependency>

    <!--数据连接池-->
    <dependency>
      <groupId></groupId>
      <artifactId>druid</artifactId>
      <version>1.2.3</version>
    </dependency>

    <!--log4j-->
    <dependency>
      <groupId>log4j</groupId>
      <artifactId>log4j</artifactId>
      <version>1.2.17</version>
    </dependency>

    <!--测试/配合spring-test进行测试类的测试（junit版本不能低于4.5）-->
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.13.1</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId></groupId>
      <artifactId>spring-test</artifactId>
      <version>5.2.</version>
      <scope>test</scope>
    </dependency>

    <!--spring-->
    <dependency>
      <groupId></groupId>
      <artifactId>spring-context</artifactId>
      <version>5.2.</version>
    </dependency>
    <dependency>
      <groupId></groupId>
      <artifactId>spring-beans</artifactId>
      <version>5.2.</version>
    </dependency>
    <dependency>
      <groupId></groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>5.2.</version>
    </dependency>
    <dependency>
      <groupId></groupId>
      <artifactId>spring-jdbc</artifactId>
      <version>5.2.</version>
    </dependency>
    <dependency>
      <groupId></groupId>
      <artifactId>spring-aspects</artifactId>
      <version>5.2.</version>
    </dependency>
    <dependency>
      <groupId></groupId>
      <artifactId>spring-context-support</artifactId>
      <version>5.2.</version>
    </dependency>
    <dependency>
      <groupId></groupId>
      <artifactId>spring-aop</artifactId>
      <version>5.2.</version>
    </dependency>
    <dependency>
      <groupId></groupId>
      <artifactId>spring-web</artifactId>
      <version>5.2.</version>
    </dependency>
    <dependency>
      <groupId></groupId>
      <artifactId>spring-core</artifactId>
      <version>5.2.</version>
    </dependency>
    <dependency>
      <groupId></groupId>
      <artifactId>spring-test</artifactId>
      <version>5.2.</version>
      <scope>test</scope>
    </dependency>

    <!--文件上传组件-->
    <dependency>
      <groupId></groupId>
      <artifactId>fastjson</artifactId>
      <version>1.2.73</version>
    </dependency>
    <dependency>
      <groupId>commons-fileupload</groupId>
      <artifactId>commons-fileupload</artifactId>
      <version>1.3.3</version>
    </dependency>

    <!--JSTL jsp页面使用的标签-->
    <dependency>
      <groupId></groupId>
      <artifactId>jstl</artifactId>
      <version>1.2</version>
    </dependency>
    <dependency>
      <groupId>taglibs</groupId>
      <artifactId>standard</artifactId>
      <version>1.1.2</version>
    </dependency>

  </dependencies>

</project>

第三步：准备一张表，并生成对应的实体类。

• @TableName：映射表名
• @TableId(type = )：映射主键自增
• @TableField(“user_account”)：映射字段名

@TableName("oa_user")
public class OaUser {

    // 主键自增
    @TableId(type = IdType.AUTO)
    private Long userId;
    
	@TableField("user_account")
    private String userAccount;

    private String userPassword;

    private String userPhone;

    private Integer userGender;
	
	// get()/set()方法......
}

第四步：修改配置文件

• 数据源配置文件：

url=jdbc:mysql://localhost:3306/oa_zan?relaxAutoCommit=true&zeroDateTimeBehavior=convertToNull
driver=
user=root
password=root

• spring的配置文件： 如果需要用到分页，需要添加分页插件。

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="/schema/beans"
       xmlns:xsi="http:///2001/XMLSchema-instance"
       xmlns:context="/schema/context"
       xsi:schemaLocation="/schema/beans
       /schema/beans/
       /schema/context
       /schema/context/">

    <!--扫描dao和service层的注解-->
    <context:component-scan base-package=""/>

    <!--引入文件、配置数据源连接-->
    <context:property-placeholder location="classpath:"/>
    <bean id="dataSource" class="">
        <property name="driverClassName" value="${driver}"/>
        <property name="url" value="${url}"/>
        <property name="username" value="${user}"/>
        <property name="password" value="${password}"/>
    </bean>

    <!--创建sqlSessionFactory对象-->
    <bean id="sqlSessionFactory" class="">
        <property name="dataSource" ref="dataSource"/>
        <property name="typeAliasesPackage" value=""/>
        <property name="configuration">
            <bean class="">
                <property name="autoMappingBehavior" value="FULL"/>
                <property name="mapUnderscoreToCamelCase" value="true"/>
            </bean>
        </property>
        <!--分页插件-->
        <property name="plugins">
            <array>
                <bean class="">
                    <property name="dbType" value="MYSQL"/>
                </bean>
            </array>
        </property>
    </bean>

    <!--递归扫描dao成接口，进行动态映射-->
    <bean class="">
        <property name="basePackage" value=""/>
    </bean>

</beans>

• SpringMVC的配置文件： （SpringMVC的配置文件不需要修改）

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="/schema/beans"
       xmlns:xsi="http:///2001/XMLSchema-instance"
       xmlns:context="/schema/context"
       xmlns:mvc="/schema/mvc"
       xsi:schemaLocation="/schema/beans /schema/beans/ /schema/context /schema/context/ /schema/mvc /schema/mvc/">

    <!--扫描controller层的注解-->
    <context:component-scan base-package=""/>

    <!--注解驱动控制器-->
    <mvc:annotation-driven>
        <mvc:message-converters>
            <bean class="">
                <property name="supportedMediaTypes">
                    <list>
                        <value>application/json;charset=UTF-8</value>
                    </list>
                </property>
            </bean>
            <bean class="">
                <property name="supportedMediaTypes">
                    <list>
                        <value>text/html;charset=UTF-8</value>
                        <value>application/json</value>
                    </list>
                </property>
                <property name="features">
                    <list>
                        <!--日期转换格式-->
                        <value>WriteDateUseDateFormat</value>
                    </list>
                </property>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>

    <!--配置视图解析器-->
    <bean class="">
        <property name="prefix" value="/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

    <!--引入静态资源-->
    <mvc:resources mapping="/**" location="/"/>

    <!--配置文件上传-->
    <bean class="">
        <!--配置文件上传大小限制和文件编码-->
        <property name="maxUploadSize" value="5000000"/>
        <property name="defaultEncoding" value="UTF-8"/>
    </bean>

</beans>

• 的配置文件可有可无。

• 的配置文件（不需要修改）

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="/xml/ns/javaee"
         xmlns:xsi="http:///2001/XMLSchema-instance"
         xsi:schemaLocation="/xml/ns/javaee
         /xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">

  <context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath:</param-value>
  </context-param>

  <listener>
    <listener-class></listener-class>
  </listener>

  <servlet>
    <servlet-name>springmvc</servlet-name>
    <servlet-class></servlet-class>
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>springmvc</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>

  <!--字符编码过滤器-->
  <filter>
    <filter-name>characterEncodingFile</filter-name>
    <filter-class></filter-class>
    <init-param>
      <param-name>encoding</param-name>
      <param-value>utf-8</param-value>
    </init-param>
  </filter>
  <filter-mapping>
    <filter-name>characterEncodingFile</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>
</web-app>

第五步：写Dao接口、继承 BaseMapper<T>

• 泛型T指定所要操作的实体类（实体类跟数据表又进行了映射）

public interface OaUserDao extends BaseMapper<OaUser> {
}

第六步：写service层调用MyBatis-Plus封装好的方法、实现具体的业务

• service 层接口的实现类，对一些常用方法进行举例。

@Service
public class OaUserServiceImpl implements OaUserService {

    @Autowired
    private OaUserDao oaUserDao;

    /**
     * 根据条件查询，条件可以为空，条件为空则为查询全部
     * @return
     */
    public List<OaUser> selectList(OaUser oaUser) {
        if (oaUser == null) {
            return oaUserDao.selectList(null);
        }
        QueryWrapper<OaUser> wrapper = new QueryWrapper<>();
        wrapper.eq("user_account" , oaUser.getUserAccount());
        return oaUserDao.selectList(wrapper);
    }

    /**
     * 根据ID查询指定用户
     * @param userId
     * @return
     */
    public OaUser selectOne(Integer userId){
        return oaUserDao.selectById(userId);
    }

    /**
     * 根据条件进行分页查询，条件可以为空
     * @param page  当前页码
     * @param rows  每页数据量
     * @return
     */
    @Override
    public List<OaUser> selectByPage(Integer page, Integer rows) {
        // 创建分页对象,包装分页数据
        IPage<OaUser> oaUserPage = new Page<>(page, rows);
        IPage<OaUser> oaUserIPage = oaUserDao.selectPage(oaUserPage, null);
        List<OaUser> records = oaUserIPage.getRecords();
        return records;
    }
    
	/**
     * 按条件查询，把条件封装到map中
     * @param map key:数据库字段，value：前端接收的值
     * @return
     */
    @Override
    public List<OaUser> selectByMap(Map map) {
        return oaUserDao.selectByMap(map);
    }

    /**
     * 批量查询
     * @param list
     * @return
     */
    @Override
    public List<OaUser> selectByBatchId(List<Integer> list) {
        return oaUserDao.selectBatchIds(list);
    }

    /**
     * 根据ID删除
     * @param userId
     * @return
     */
    @Override
    public int deleteById(Integer userId) {
        return oaUserDao.deleteById(userId);
    }

    /**
     * 根据ID批量删除
     * @param list
     * @return
     */
    @Override
    public int deleteBatchIds(List<Integer> list) {
        return oaUserDao.deleteBatchIds(list);
    }

    /**
     * 通过指定条件删除，把条件封装的map中
     * @param map key：数据库的字段。value：值
     * @return
     */
    @Override
    public int deleteMap(Map map) {
        return oaUserDao.deleteByMap(map);
    }
}

• 测试示例

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:")
public class TestMyBatisPlus {
	@Test
    public void test(){
        Map<String, String> map = new HashMap<>();
        map.put("user_account" , "aaa");
        map.put("user_password" , "aaa");
        oaUserService.selectByMap(map).forEach(System.out::println);
    }
}

第七步：实现controller层，进行页面交互

@Controller
@RequestMapping("/user")
public class OaUserController {

    @Autowired
    private OaUserService oaUserService;

    @RequestMapping("/query")
    public String getAll(OaUser oaUser , Model model){
        List<OaUser> userList = oaUserService.selectList(oaUser);
        model.addAttribute("userList" , userList);
        return "index";
    }

    @RequestMapping("/getOne")
    public String selectById(Integer userId , Model model){
        OaUser oaUser = oaUserService.selectOne(userId);
        model.addAttribute("oaUser" , oaUser);
        return "details";
    }
}

最后一步：jsp页面数据展示

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
<%@ taglib prefix="c" uri="/jsp/jstl/core" %>

<html>
<title>首页</title>
<style type="text/css">
    #customers {
        text-align: center;
        font-family: "Trebuchet MS", Arial, Helvetica, sans-serif;
        width: 100%;
    }

    #customers th {
        height: 50px;
        font-size: 1.1em;
        text-align: center;
        padding-top: 5px;
        padding-bottom: 4px;
        background-color: #A7C942;
        color: #ffffff;
    }

    #customers td {
        height: 50px;
    }
</style>
</head>
<body>
<div style="width: 100%;text-align: center">
    <h1>用户查询查询</h1>
</div>
<table id="customers">
    <tr>
        <th>用户账户</th>
        <th>用户电话</th>
        <th>用户性别</th>
        <th>创建时间</th>
        <th>操作</th>
    </tr>
    <c:forEach items="${userList}" var="userList" varStatus="i">
            <tr style="background-color: powderblue">
                <td>${}</td>
                <td>${}</td>
                <c:choose>
                    <c:when test="${ == 1}">
                        <td>男</td>
                    </c:when>
                    <c:when test="${ == 0}">
                        <td>女</td>
                    </c:when>
                </c:choose>
                <td>${}</td>
                <td><a href="#">查询</a></td>
            </tr>
        </c:if>
    </c:forEach>
</table>

</body>
</html>

条件构造器（重要）

有些复杂的SQL我们需要用到 官方网址

常用词解释：

• where WHERE 语句，拼接 + WHERE 条件
• and AND 语句，拼接 + AND 字段=值
• andNew AND 语句，拼接 + AND (字段=值) （新的括号）
• or OR 语句，拼接 + OR 字段=值
• orNew OR 语句，拼接 + OR (字段=值)
• eq 等于=
• allEq 基于 map 内容等于=
• ne 不等于<>
• gt 大于>
• ge 大于等于>=
• lt 小于<
• le 小于等于<=
• like 模糊查询 LIKE
• notLike 模糊查询 NOT LIKE
• in IN 查询
• notIn NOT IN 查询
• isNull NULL 值查询
• isNotNull IS NOT NULL
• groupBy 分组 GROUP BY
• having HAVING 关键词
• orderBy 排序 ORDER BY
• orderAsc ASC 排序 ORDER BY
• orderDesc DESC 排序 ORDER BY
• exists EXISTS 条件语句
• notExists NOT EXISTS 条件语句
• between BETWEEN 条件语句
• notBetween NOT BETWEEN 条件语句
• addFilter *拼接 SQL
• last 拼接在最后，例如：last(“LIMIT 1”)

示例：

• service的实现类：

@Override
    public List<OaUser> getByList(Wrapper wrapper) {
        return oaUserDao.selectList(wrapper);
    }

    @Override
    public List<OaUser> getByListName(Wrapper wrapper) {
        return oaUserDao.selectList(wrapper);
    }

• 测试类

@Test
    public void test01() {
        // 查询user_account不为空的用户，并且密码不为空的用户，性别为男的
        QueryWrapper<OaUser> wrapper = new QueryWrapper<>();
        wrapper.isNotNull("user_account")
               .isNotNull("user_password")
               .eq("user_gender", 1);
        oaUserService.getByList(wrapper).forEach(System.out::println);
    }

    @Test
    public void test02(){
        // 查询名字
        QueryWrapper<OaUser> wrapper = new QueryWrapper<>();
        wrapper.eq("user_account","aaa");
        // 查询一个数据，出现多个结果使用List 或者 Map
        List<OaUser> byListName = oaUserService.getByListName(wrapper);
        System.out.println(byListName);
    }