Spring整合Mybatis详解(手把手教你8步搞定)

第一步：增加mybatis相关依赖

我们只需要加上pom.xml文件这些依赖即可。

       <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.41</version>
        </dependency>
        <!--mybatis-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.1</version>
        </dependency>
        <!--mapper-->
        <dependency>
            <groupId>tk.mybatis</groupId>
            <artifactId>mapper-spring-boot-starter</artifactId>
            <version>1.2.4</version>
        </dependency>
        <!-- pagehelper -->
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper-spring-boot-starter</artifactId>
            <version>1.2.3</version>
        </dependency>
        <!-- druid 数据库连接框架-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.9</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis.generator</groupId>
            <artifactId>mybatis-generator-core</artifactId>
            <version>1.3.2</version>
            <scope>compile</scope>
            <optional>true</optional>
        </dependency>

第二步：增加统一的mapper接口

在utils包中创建一个统一的mapper接口，后面所有的mapper类都会继承这个接口。

package com.mikechen.utils;

import tk.mybatis.mapper.common.Mapper;
import tk.mybatis.mapper.common.MySqlMapper;

/**
 * 继承自己的MyMapper
 *
 */
public interface MyMapper<T> extends Mapper<T>, MySqlMapper<T> {
    //TODO
    //FIXME 特别注意，该接口不能被扫描到，否则会出错
}

特别注意：该接口不能被扫描到，否则会出错。所以我把这个接口放在了utils包中。

第三步：更改application.properties配置文件

主要是mybatis相关的数据库配置。

############################################################
# 数据源相关配置，这里用的是阿里的druid 数据源
############################################################
spring.datasource.url=jdbc:mysql://localhost:3306/zwz_test
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.druid.initial-size=1
spring.datasource.druid.min-idle=1
spring.datasource.druid.max-active=20
spring.datasource.druid.test-on-borrow=true
spring.datasource.druid.stat-view-servlet.allow=true

############################################################
# mybatis 相关配置
############################################################
mybatis.type-aliases-package=com.weiz.pojo
mybatis.mapper-locations=classpath:mapper/*.xml
mapper.mappers=com.weiz.utils.MyMapper    #这个MyMapper 就是我之前创建的mapper统一接口。后面所有的mapper类都会继承这个接口
mapper.not-empty=false
mapper.identity=MYSQL
# 分页框架
pagehelper.helperDialect=mysql
pagehelper.reasonable=true
pagehelper.supportMethodsArguments=true
pagehelper.params=count=countSql

这里的配置有点多，不过最基本的配置都在这。

第四步：Mybatis Generator自动生成代码

创建GeneratorDisplay类,运行即可自动生成相关的代码，如下所示：

package com.mikechen.utils;

import java.io.File;
import java.util.ArrayList;
import java.util.List;

import org.mybatis.generator.api.MyBatisGenerator;
import org.mybatis.generator.config.Configuration;
import org.mybatis.generator.config.xml.ConfigurationParser;
import org.mybatis.generator.internal.DefaultShellCallback;

public class GeneratorDisplay {

    public void generator() throws Exception{

        List<String> warnings = new ArrayList<String>();
        boolean overwrite = true;
        //指定 逆向工程配置文件
        File configFile = new File("generatorConfig.xml"); 
        ConfigurationParser cp = new ConfigurationParser(warnings);
        Configuration config = cp.parseConfiguration(configFile);
        DefaultShellCallback callback = new DefaultShellCallback(overwrite);
        MyBatisGenerator myBatisGenerator = new MyBatisGenerator(config,
                callback, warnings);
        myBatisGenerator.generate(null);

    } 
    
    public static void main(String[] args) throws Exception {
        try {
            GeneratorDisplay generatorSqlmap = new GeneratorDisplay();
            generatorSqlmap.generator();
        } catch (Exception e) {
            e.printStackTrace();
        }
        
    }
}

第五步：在service包下创建UserService及UserServiceImpl接口实现类

1、创建UserService接口类

public interface UserService {

    public void saveUser(SysUser user) throws Exception;

    public void updateUser(SysUser user);

    public void deleteUser(String userId);

    public SysUser queryUserById(String userId);

    public List<SysUser> queryUserList(SysUser user);

    public List<SysUser> queryUserListPaged(SysUser user, Integer page, Integer pageSize);public void saveUserTransactional(SysUser user);
}

2、创建UserServiceImpl实现类

import java.util.List;

@Service
public class UserServiceImpl implements UserService {

    @Autowired
    private SysUserMapper userMapper;

    @Override
    public void saveUser(SysUser user) throws Exception {
        userMapper.insert(user);
    }

    @Override
    public void updateUser(SysUser user) {
        userMapper.updateByPrimaryKeySelective(user);
    }

    @Override
    public void deleteUser(String userId) {
        userMapper.deleteByPrimaryKey(userId);
    }

    @Override
    public SysUser queryUserById(String userId) {
        return userMapper.selectByPrimaryKey(userId);
    }

    @Override
    public List<SysUser> queryUserList(SysUser user) {
        return null;
    }

    @Override
    public List<SysUser> queryUserListPaged(SysUser user, Integer page, Integer pageSize) {
　　　　 // 分页功能实现
        PageHelper.startPage(page,pageSize);
        Example example = new Example(SysUser.class);
        Example.Criteria criteria = example.createCriteria();

        if (!StringUtils.isEmptyOrWhitespace(user.getUsername())) {
            criteria.andLike("username", "%" + user.getUsername() + "%");
        }

        if (!StringUtils.isEmptyOrWhitespace(user.getNickname())) {
            criteria.andLike("nickname", "%" + user.getNickname() + "%");
        }

        List<SysUser> userList = userMapper.selectByExample(example);

        return userList;
    }

    @Override
    public void saveUserTransactional(SysUser user) {

    }
}

第六步：编写controller层，增加MybatisController控制器

package com.weiz.controller;

import com.weiz.utils.JSONResult;
import com.weiz.pojo.SysUser;
import com.weiz.service.UserService;
import org.n3r.idworker.Sid;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.Date;
import java.util.List;

@RestController
@RequestMapping("mybatis")
public class MyBatisCRUDController {

    @Autowired
    private UserService userService;

    @Autowired
    private Sid sid;

    @RequestMapping("/saveUser")
    public JSONResult saveUser() throws Exception {
　　　　 // 自动生成ID，也可以直接用uuid
        String userId = sid.nextShort();

        SysUser user = new SysUser();
        user.setId(userId);
        user.setUsername("spring boot" + new Date());
        user.setNickname("spring boot" + new Date());
        user.setPassword("abc123");
        user.setIsDelete(0);
        user.setRegistTime(new Date());

        userService.saveUser(user);

        return JSONResult.ok("保存成功");
    }

    @RequestMapping("/updateUser")
    public JSONResult updateUser() {

        SysUser user = new SysUser();
        user.setId("10011001");
        user.setUsername("10011001-updated" + new Date());
        user.setNickname("10011001-updated" + new Date());
        user.setPassword("10011001-updated");
        user.setIsDelete(0);
        user.setRegistTime(new Date());

        userService.updateUser(user);

        return JSONResult.ok("保存成功");
    }


    @RequestMapping("/deleteUser")
    public JSONResult deleteUser(String userId) {

        userService.deleteUser(userId);

        return JSONResult.ok("删除成功");
    }

    @RequestMapping("/queryUserById")
    public JSONResult queryUserById(String userId) {

        return JSONResult.ok(userService.queryUserById(userId));
    }

    @RequestMapping("/queryUserList")
    public JSONResult queryUserList() {

        SysUser user = new SysUser();
        user.setUsername("spring boot");
        user.setNickname("lee");

        List<SysUser> userList = userService.queryUserList(user);

        return JSONResult.ok(userList);
    }

    @RequestMapping("/queryUserListPaged")
    public JSONResult queryUserListPaged(Integer page) {
        if (page == null) {
            page = 1;
        }

        int pageSize = 10;

        SysUser user = new SysUser();

        List<SysUser> userList = userService.queryUserListPaged(user, page, pageSize);

        return JSONResult.ok(userList);
    }

    @RequestMapping("/queryUserByIdCustom")
    public JSONResult queryUserByIdCustom(String userId) {

        return JSONResult.ok(userService.queryUserByIdCustom(userId));
    }

    @RequestMapping("/saveUserTransactional")
    public JSONResult saveUserTransactional() {

        String userId = sid.nextShort();

        SysUser user = new SysUser();
        user.setId(userId);
        user.setUsername("lee" + new Date());
        user.setNickname("lee" + new Date());
        user.setPassword("abc123");
        user.setIsDelete(0);
        user.setRegistTime(new Date());

        userService.saveUserTransactional(user);

        return JSONResult.ok("保存成功");
    }


}

第七步：在启动主类添加扫描器

在SpringBootStarterApplication 启动类中增加包扫描器。

@SpringBootApplication
//扫描 mybatis mapper 包路径
@MapperScan(basePackages = "com.mikechen.mapper")     
//扫描 所有需要的包, 包含一些自用的工具类包 所在的路径
@ComponentScan(basePackages = {"com.mikechen","org.n3r.idworker"})
public class SpringBootStarterApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringBootStarterApplication.class, args);
    }

}

第八步：测试

在浏览器输入controller里面定义的路径即可，只要你按照上面的步骤一步一步来，基本上就没问题。