完整源码下载：https://pan.baidu.com/s/1rNQKSnqGEO2eQJYdd0UJwA 提取码: 59s5

前篇 SpringBoot+JdbcTemplate实现数据库多联表增删改查及分页实例

这次用Mybatis重构,之后工作中大概用的比较多

相比Jpa和JdbcTemplate复杂一些，多了几个配置文件，数据库查询方式也是更像HTML风格，实体类服务层dao接口倒是简化了很多，只用写一个了

开发环境：

IDE：IDEA

开发框架：SpringBoot、Maven

JDK版本：1.8

数据库：MySql 5.7.28

调试软件：Postman安装与使用

数据库结构

1. 用户表结构：id 名字 密码 邮箱
2. 角色表结构：id 角色名
3. 用户-角色表结构：id 用户id 角色id

功能总结：

1. 增加用户
2. 更新用户
3. 根据id删除用户
4. 根据id查找用户
5. 根据用户名查找用户 (模糊查询)
6. 分页展示所有用户
7. 根据用户id增加角色
8. 根据用户id删除指定角色
9. 根据用户id查询所有角色
10. 根据用户名查询所有角色
11. 根据角色id查询所有用户
12. 根据角色名查询所有用户

项目结构： 

新建项目：

打开IDEA->File->New->Project，选择Spring Initializr

然后修改Group名称，Type选择Maven，Java version选择8   (JDK8和JDK1.8是一样的)

依次选择如右侧的配置 

修改工程文件名，新建项目完成

代码文件

首先是Mybats的配置文件，分别创建这三个包和类

主要是用来配置数据库（也可以不写，不过我删了之后就跑不起来了。。

可以直接复制，包名改成自己的就行了

DataSourceConfiguration类

package com.example.mybatis.demo.config.dao;

import com.mchange.v2.c3p0.ComboPooledDataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.beans.PropertyVetoException;

/**
 * 数据库配置类
 */
@Configuration
public class DataSourceConfiguration {

    @Value("${jdbc.driver}")
    private String jdbcDriver;
    @Value("${jdbc.url}")
    private String jdbcUrl;
    @Value("${jdbc.username}")
    private String jdbcUsername;
    @Value("${jdbc.password}")
    private String jdbcPassword;

    @Bean(name = "dataSouce")
    public ComboPooledDataSource createDataSouce() throws PropertyVetoException {
        ComboPooledDataSource dataSource = new ComboPooledDataSource();
        dataSource.setDriverClass(jdbcDriver);
        dataSource.setJdbcUrl(jdbcUrl);
        dataSource.setUser(jdbcUsername);
        dataSource.setPassword(jdbcPassword);
        //关闭连接后不自动commit
        dataSource.setAutoCommitOnClose(false);
        return dataSource;
    }
}

SessionFactoryConfiguration类

package com.example.mybatis.demo.config.dao;

import org.mybatis.spring.SqlSessionFactoryBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;

import javax.sql.DataSource;
import java.io.IOException;

/**
 * 数据库sqlSession配置类
 */

@Configuration
public class SessionFactoryConfiguration {

    @Value("${mapper_path}")
    private String mapperPath;

    @Value("${mybatis_config_file}")
    private String mybatisConfigFilePath;

    @Autowired
    private DataSource dataSouce;
    @Value("${entity_package}")
    private String entityPackage;

    @Bean(name="sqlSessionFactory")
    public SqlSessionFactoryBean createSqlSessionFactoryBean() throws IOException {
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setConfigLocation(new ClassPathResource(mybatisConfigFilePath));
        PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        String packageSearchPath = PathMatchingResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX+mapperPath;
        sqlSessionFactoryBean.setMapperLocations(resolver.getResources(packageSearchPath));
        sqlSessionFactoryBean.setDataSource(dataSouce);
        sqlSessionFactoryBean.setTypeAliasesPackage(entityPackage);
        return sqlSessionFactoryBean;
    }
}

 TransactionManagementConfiguration类

package com.example.mybatis.demo.config.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import org.springframework.transaction.annotation.TransactionManagementConfigurer;

import javax.sql.DataSource;

/**
 * 事务配置类，不可缺少，尚未知具体作用
 */
@Configuration
@EnableTransactionManagement
public class TransactionManagementConfiguration implements TransactionManagementConfigurer{

    @Autowired
    private DataSource dataSource;

    @Override
    public PlatformTransactionManager annotationDrivenTransactionManager() {
        return new DataSourceTransactionManager(dataSource);
    }
}

pom.xml配置文件

多了一个线程池配置

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.4.2</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example.mybaties</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.4</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!--线程池-->
        <dependency>
            <groupId>com.mchange</groupId>
            <artifactId>c3p0</artifactId>
            <version>0.9.5.4</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

application.properties配置文件

更喜欢yml文件的格式,不过不知道mybatis的部分怎么改...

注意数据库的配置，改成自己的

#1.项目启动的端口
server.port=8080
#2.数据库连接参数
#2.1jdbc驱动，示数据库厂商决定，这是mysql的驱动
jdbc.driver=com.mysql.cj.jdbc.Driver
#2.2数据库连接url，包括ip(127.0.0.1)、端口(3306)、数据库名(testdb)
jdbc.url=jdbc:mysql://127.0.0.1:3306/你的数据库?useUnicode=true&characterEncoding=utf-8&useSSL=false
#2.3数据库账号名
jdbc.username=你的账号名
#2.4数据库密码
jdbc.password=你的密码
#3.Mybatis配置
#3.1 mybatis配置文件所在路径
mybatis_config_file=mybatis-config.xml
#3.2 mapper文件所在路径，这样写可匹配mapper目录下的所有mapper，包括其子目录下的
mapper_path=/mapper/*.xml
#3.3 entity所在包
entity_package=com.example.mybatis.demo.entity

实体类

新建文件夹entity，创建实体类User

package com.example.mybatis.demo.entity;

public class User {

    protected Integer id;

    protected String name;

    protected String password;

    protected String email;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }
}

创建实体类Role 

package com.example.mybatis.demo.entity;

public class Role {

    private Integer id;

    private String role;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getRole() {
        return role;
    }

    public void setRole(String role) {
        this.role = role;
    }
}

创建实体类User_Role

package com.example.mybatis.demo.entity;

public class User_Role {

    private Integer id;

    private Integer user_id;

    private Integer role_id;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public Integer getUser_id() {
        return user_id;
    }

    public void setUser_id(Integer user_id) {
        this.user_id = user_id;
    }

    public Integer getRole_id() {
        return role_id;
    }

    public void setRole_id(Integer role_id) {
        this.role_id = role_id;
    }
}

 

Dao接口

新建文件夹dao，创建接口类文件userDao

接口类文件创建方法：对应文件夹右键，New->Java Class，然后选择Interface创建

package com.example.mybatis.demo.dao;

import com.example.mybatis.demo.entity.Role;
import com.example.mybatis.demo.entity.User;
import com.example.mybatis.demo.entity.User_Role;
import org.apache.ibatis.annotations.Mapper;

import java.util.List;

@Mapper
public interface Dao {

    int addUser(User user);

    User findById(Integer id);

    int addRoleById(User_Role user_role);

    int delRoleById(User_Role user_role);

    int update(User user);

    List<User> findByName(String name);

    int delete(Integer id);

    List<Role> findRoleByUserName(String name);

    List<User> findUserByRoleName(String name);

    List<Role> findRoleByUserId(Integer id);

    List<User> findUserByRoleId(Integer id);

    List<User> findAll(Integer page);

}

 

服务层接口类

新建文件夹service，创建a接口类文件UserService

package com.example.mybatis.demo.service;

import com.example.mybatis.demo.dao.Dao;
import com.example.mybatis.demo.entity.Role;
import com.example.mybatis.demo.entity.User;
import com.example.mybatis.demo.entity.User_Role;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class UserService {

    @Autowired
    private Dao Dao;

    public int addUser(User user) {
        return Dao.addUser(user);
    }

    public User findById(Integer id) {
        return Dao.findById(id);
    }

    //根据名字查找
    public List<User> findByName(String name) {
        return Dao.findByName(name);
    }

    //根据用户名查找用户所有的角色
    public List<Role> findRoleByUserName(String name) {
        return Dao.findRoleByUserName(name);
    }

    //根据角色名查找所有的用户
    public List<User> findUserByRoleName(String name) {
        return Dao.findUserByRoleName(name);
    }

    //根据id删除
    public int deleteById(Integer id) {
        return Dao.delete(id);
    }

    public int addRoleById(User_Role user_role) {
        return Dao.addRoleById(user_role);
    }

    public int delRoleById(User_Role user_role) {
        return Dao.delRoleById(user_role);
    }

    public int updateUser(User user) {
        return Dao.update(user);
    }

    public List<Role> findRoleByUserId(Integer id) {
        return Dao.findRoleByUserId(id);
    }

    public List<User> findUserByRoleId(Integer id) {
        return Dao.findUserByRoleId(id);
    }

    //查询所有
    public List<User> findAll(Integer page) {
        return Dao.findAll(page);
    }
}

控制层

新建文件夹controller，创建控制类文件UserController

功能注释都在这里了

package com.example.mybatis.demo.controller;

import com.example.mybatis.demo.entity.Role;
import com.example.mybatis.demo.entity.User;
import com.example.mybatis.demo.entity.User_Role;
import com.example.mybatis.demo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;
import java.util.Map;

@RestController
@RequestMapping("/emp")
public class Controller {

    @Autowired
    private UserService userService;

    /**
     * 增加用户
     *
     * @param user
     * @return
     */
    @PutMapping("/add")
    public String add(User user) {
        userService.addUser(user);
        return "增加用户成功";
    }

    /**
     * 根据id删除用户
     *
     * @param id
     * @return
     */
    @DeleteMapping("/delById/{id}")
    public String delById(@PathVariable Integer id) {
        userService.deleteById(id);
        return "删除用户成功";
    }

    /**
     * 通过id查找用户
     *
     * @param id
     * @return
     */
    @GetMapping("/findById/{id}")
    public User findById(@PathVariable Integer id) {
        System.out.println("id:" + id);
        return userService.findById(id);
    }

    /**
     * 通过用户名模糊查询
     *
     * @param name
     * @return
     */
    @GetMapping("/findByName/{name}")
    public List<User> findByName(@PathVariable String name) {
        return userService.findByName(name);
    }

    /**
     * 更新用户信息
     *
     * @param user
     * @return
     */
    @PostMapping("/update")
    public String update(User user) {
        userService.updateUser(user);
        return "更新用户成功";
    }

    /**
     * 通过用户名查找所有角色
     *
     * @param name
     * @return
     */
    @GetMapping("/findRoleByUserName/{name}")
    public List<Role> findRoleByUserName(@PathVariable String name) {
        return userService.findRoleByUserName(name);
    }

    /**
     * 通过角色名查找所有用户
     *
     * @param name
     * @return
     */
    @GetMapping("/findUserByRoleName/{name}")
    public List<User> findUserByRoleName(@PathVariable String name) {
        return userService.findUserByRoleName(name);
    }

    /**
     * 根据用户id查找角色
     *
     * @param id
     * @return
     */
    @GetMapping("/findRoleByUserId/{id}")
    public List<Role> findRoleByUserId(@PathVariable Integer id) {
        return userService.findRoleByUserId(id);
    }

    /**
     * 根据角色id查找用户
     *
     * @return
     */
    @GetMapping("/findUserByRoleId/{id}")
    public List<User> findUserByRoleId(@PathVariable Integer id) {
        return userService.findUserByRoleId(id);
    }

    /**
     * 分页查看所有用户
     *
     * @param page
     * @return
     */
    @GetMapping("/findAll/{page}")
    public List<User> findAll(@PathVariable Integer page) {
        page = (page - 1) * 5;
        return userService.findAll(page);
    }

    /**
     * 通过用户id和角色id增加角色
     *
     * @param user_role
     * @return
     */
    @PutMapping("/addRoleById")
    public String addRoleById(User_Role user_role) {
        userService.addRoleById(user_role);
        return "增加角色成功";
    }

    /**
     * 通过用户id和角色id删除指定角色
     *
     * @param user_role
     * @return
     */
    @DeleteMapping("/delRoleById")
    public String delRoleById(User_Role user_role) {
        userService.delRoleById(user_role);
        return "删除角色成功";
    }
}

关联层

在resouces文件夹下新建mapper包，创建DaoMapper.xml文件

这里是Mybatis写SQL语句的地方，风格类似HTML标签

传递List数据类型的时候需要写一个RestMap，将主要参数写进去

模糊查询那里(findByName)需要注意一下格式，使用concat将%与参数连接起来

<?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.example.mybatis.demo.dao.Dao">
    <!-- 根据主键查询-->
    <!--SQL操作方法  返回参数格式  传入参数格式参数-->
    <select id="findById" resultType="com.example.mybatis.demo.entity.User" parameterType="java.lang.Integer" >
        select * from user where id = #{id}
    </select>
    <insert id="addUser" parameterType="com.example.mybatis.demo.entity.User" >
        INSERT INTO user(id,name,password,email) VALUE(#{id},#{name},#{password},#{email})
    </insert>
    <delete id="delete" parameterType="java.lang.Integer" >
        DELETE FROM user where id = #{id}
    </delete>
    <update id="update" parameterType="com.example.mybatis.demo.entity.User" >
        UPDATE user
        <set>
            <if test="name!=null and name!='' ">
                name= #{name},
            </if>
            <if test="password!=null">
                password= #{password},
            </if>
            <if test="email!=null">
                email= #{email},
            </if>
        </set>
        WHERE id= #{id};
    </update>
    <resultMap id="result" type="com.example.mybatis.demo.entity.User">
        <result property="id" column="id" />
        <result property="name" column="name" />
        <result property="password" column="password"/>
        <result property="email" column="email"/>
    </resultMap>
    <select id="findByName" resultMap="result" parameterType="java.lang.String">
        SELECT user.id,user.name,user.password,user.email FROM user WHERE name like concat('%',#{name},'%')
    </select>
    <resultMap id="resultRole" type="com.example.mybatis.demo.entity.Role">
        <result property="id" column="id" />
        <result property="role" column="role" />
    </resultMap>
    <select id="findRoleByUserName" resultMap="resultRole" parameterType="java.lang.String">
        SELECT role.id,role.role FROM user_role,role WHERE user_role.user_id = (SELECT id FROM user WHERE user.name = #{name}) AND role.id = user_role.role_id;
    </select>
    <select id="findUserByRoleName" resultMap="result" parameterType="java.lang.String">
        SELECT user.id,user.name,user.password,user.email FROM user_role,user WHERE user_role.role_id = (SELECT id FROM role WHERE role.role = #{name}) AND user.id = user_role.user_id;
    </select>
    <select id="findRoleByUserId" resultMap="resultRole" parameterType="java.lang.Integer">
        SELECT role.id,role.role FROM user_role,role WHERE user_role.user_id = #{id} AND role.id = user_role.role_id;
    </select>
    <select id="findUserByRoleId" resultMap="result" parameterType="java.lang.Integer">
        SELECT user.id,user.name,user.password,user.email FROM user_role,user WHERE user_role.role_id = #{id} AND user.id = user_role.user_id;
    </select>
    <select id="findAll" resultMap="result" parameterType="java.lang.Integer">
        SELECT * FROM user LIMIT #{page},5;
    </select>
    <insert id="addRoleById" parameterType="com.example.mybatis.demo.entity.User_Role">
        INSERT INTO user_role(user_id,role_id) VALUE(#{user_id},#{role_id})
    </insert>
    <delete id="delRoleById" parameterType="java.lang.Integer">
        DELETE FROM user_role where user_id = #{user_id} AND role_id = #{role_id}
    </delete>
</mapper>

整体文件结构在文章开头

数据库结构：

user 用户表

id为主键自增非空，int类型
name非空  varchar(10)类型
password   varchar(16)类型
email         varchar(40) 类型
 

role 角色表

 user_role 用户角色关联表

 

测试：

查询全体

查询id

注意链接格式，在源码controller类中使用了RESTful规范进行查询操作

查询名字

增加用户

使用put方法进行传参，id自增所以不用加上

更新用户

删除用户

分页展示

实习的学习过程主要是做了这些，该去实战了(搬砖)