第五篇：springboot整合mybatis

什么是 MyBatis ？

mybatis是一款优秀的持久层框架，它支持定制化SQL、存储过程以及高级映射。Mybatis避免了几乎所有的JDBC代码和手动设置参数以及获取结果集。Mybatis可以使用简单的XML或注解来配置和映射原生信息，将接口和Java的pojo object映射成数据库中的记录。

创建一个新工程，引入的pom如下：

<?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>com.wujie</groupId>
    <artifactId>springboot-mybatis</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>springboot-mybatis</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- https://mvnrepository.com/artifact/com.alibaba/druid -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.10</version>
        </dependency>

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>


</project>

配置数据源：

#数据库访问配置
#主数据源，默认的
spring:
  datasource:
    url: jdbc:mysql://localhost:3306/my?useUnicode=true&characterEncoding=utf8&useSSL=false
    type: com.alibaba.druid.pool.DruidDataSource
    driver-class-name: com.mysql.jdbc.Driver
    username: root
    password: root
    #下面为连接池补充设置，应用到上面所有的数据源中
    #初始化大小
    tomcat:
      initial-size: 5
      min-idle: 5
      max-active: 20
      max-wait: 60000  #设置超时时间
      time-between-eviction-runs-millis: 60000   #配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒
      min-evictable-idle-time-millis: 30000         #配置一个链接在池中的最小生存时间
      validation-query: select 'X'
      test-while-idle: true
      test-on-borrow: false
      test-on-return: false
server:
  port: 80
mybatis:
  mapper-locations: classpath:com/wujie/springbootmybatis/mapper/*.xml

然后使用逆向生成工具帮助我们生成pojo、dao、mapper文件，为我们大大的节约了我们的开发时间。（工具在后面）

创建service

public interface StudentService {
    int deleteByPrimaryKey(Integer id);

    int insertSelective(StudentEntity record);

    StudentEntity selectByPrimaryKey(Integer id);

    List<StudentEntity> findALl();

    int updateByPrimaryKeySelective(StudentEntity record);

}

创建service的实现

 

@Service
public class StudentServiceImpl implements StudentService {
    @Autowired
    private StudentDao studentDao;
    @Override
    public int deleteByPrimaryKey(Integer id) {
        return studentDao.deleteByPrimaryKey(id);
    }

    @Override
    public int insertSelective(StudentEntity record) {
        return studentDao.insertSelective(record);
    }

    @Override
    public StudentEntity selectByPrimaryKey(Integer id) {
        return studentDao.selectByPrimaryKey(id);
    }

    @Override
    public List<StudentEntity> findALl() {
        return studentDao.findAll();
    }

    @Override
    public int updateByPrimaryKeySelective(StudentEntity record) {
        return studentDao.updateByPrimaryKeySelective(record);
    }
}

创建controller

@RestController
@RequestMapping("student")
public class StudentController {
    @Autowired
    private StudentService studentService;
    @RequestMapping("add")
    public String add(StudentEntity studentEntity){
        Integer i = studentService.insertSelective(studentEntity);
        if (i != 1) {
            return "add fail";
        }else{
            return "add success";
        }
    }

    @RequestMapping("update")
    public String update(StudentEntity studentEntity){
        Integer i = studentService.updateByPrimaryKeySelective(studentEntity);
        if (i != 1) {
            return "update fail";
        }else{
            return "update success";
        }
    }

    @RequestMapping("list")
    public Object list(Integer id){
        if(id != null){
            StudentEntity studentEntity = studentService.selectByPrimaryKey(id);
            if(studentEntity != null){
                return studentEntity;
            }else {
                return " this id is not data";
            }
        }else {
            List<StudentEntity> aLl = studentService.findALl();
            if (aLl != null && aLl.size() > 0) {
                return aLl;
            }else {
                return "data is null";
            }
        }

    }

    @RequestMapping("delete")
    public String delete(Integer id){
        Integer i = studentService.deleteByPrimaryKey(id);
        if (i != 1) {
            return "delete fail";
        }else {
            return "delete success";
        }
    }
}

注意：

我在运行的时候报错了Invalid bound statement (not found): com.wujie.springbootmybatis.dao.StudentDao.findALl，找不到对应的方法，我们可以按照以下步骤一一排除：

1. 查看我们的对应dao以及mapper是否有错
2. 查看mapper文件位置是否配置
3. 查看启动类上是否加了@MapperScan（"mapper地址"）注解
4. 查看target中是否有xml文件，如果没有请在pom中添加

<resources>
            <resource>
                <directory>${basedir}/src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
        </resources>

经过以上步骤，基本上就能够解决，如果还不能解决，请联系我！

欢迎关注我的公众号我们一起学习：

源码地址

mybatis逆向生成工具