spring boot +mybatis整合 1.创建spring boot工程 file——>new——>project——>spring initializr 创建完成后目录结构如下 配置配置文件application.properties

#页面热加载 spring.thymeleaf.cache = false #配置请求的默认上下文路径 server.servlet.context-path=/springboot0525 #端口号 server.port=8888 # 数据库访问配置 spring.datasource.url = jdbc:mysql://localhost:3306/test01?useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC spring.datasource.username = root spring.datasource.password = 123456 spring.datasource.driverClassName = com.mysql.jdbc.Driver spring.datasource.max-idle=10 spring.datasource.max-wait=10000 spring.datasource.min-idle=5 spring.datasource.initial-size=5 #配置实体类包扫描 mybatis.type-aliases-package=com.linewell.springboot0525.model #配置mapper.xml文件扫描 mybatis.mapper-locations=classpath:mappers/*.xml #视图解析器 spring.mvc.view.prefix=/ spring.mvc.view.suffix=.jsp

mybatis.mapper-locations=classpath:mappers/*.xml配置中的classpath路径是基于resource路径填写mapper.xml文件的路径 mybatis.type-aliases-package=com.linewell.springboot0525.model填写mapper.xml对应的实体类的完整包路径

也可以不使用application.properties，在application.yml文件中配置，如下方式配置（只是举个例子，yml的配置文件不全），当然也可以使用二者结合，将不同的内容分别配置在这两个文件中，不要重复配置同一内容。yml文件根据有层次，变量与值之间以冒号隔开，冒号后要有空格，.properties文件中变量与之之间是以等号隔开

server: servlet: context-path: /springboot0525 port: 8888 maxHttpHeaderSize : 3145728 mybatis: typeAliasesPackage: com.linewell.springboot0525.model mapper-locations: classpath:mappers/*.xml

配置开始编写代码 注意spring boot的主程序上要配上mapper.java文件的包扫描 代码编写完成后的目录结构如下 代码如下： UserController文件

package com.linewell.springboot0525.controller; import com.linewell.springboot0525.model.UserPO; import com.linewell.springboot0525.service.UserService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.ResponseBody; @Controller @RequestMapping("user") public class UserController { @Autowired private UserService userService; @ResponseBody @RequestMapping("/getUser") public UserPO getUserById(int id){ System.out.println("=======Controller=====id==="+id); UserPO userPO = userService.getUserById(id); return userPO; } }

UserMapper文件

package com.linewell.springboot0525.dao; import com.linewell.springboot0525.model.UserPO; public interface UserMapper { UserPO getUserById(int id); }

UserPO文件

package com.linewell.springboot0525.model; public class UserPO { private int id; private String username; private int age; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } @Override public String toString() { return "UserPO{" + "id=" + id + ", username='" + username + '\'' + ", age=" + age + '}'; } }

UserServiceImpl文件

package com.linewell.springboot0525.service.impl; import com.linewell.springboot0525.dao.UserMapper; import com.linewell.springboot0525.model.UserPO; import com.linewell.springboot0525.service.UserService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import javax.annotation.Resource; @Service public class UserServiceImpl implements UserService { @Autowired UserMapper userMapper; @Override public UserPO getUserById(int id) { System.out.println("======ServiceImpl==id==="+ id); UserPO userPO = userMapper.getUserById(id); return userPO; } }

UserService

package com.linewell.springboot0525.service; import com.linewell.springboot0525.model.UserPO; import org.springframework.stereotype.Service; public interface UserService { UserPO getUserById(int id); }

Springboot0525Application文件

package com.linewell.springboot0525; import org.mybatis.spring.annotation.MapperScan; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication @MapperScan("com.linewell.springboot0525.dao") public class Springboot0525Application { public static void main(String[] args) { SpringApplication.run(Springboot0525Application.class, args); } }

如果在serviceImpl层中userMapper上添加 @Autowired后提示Could not autowire. No beans of ‘UserMapper’ type found @Autowired UserMapper userMapper; 可以pom文件中添加如下依赖

UserMapper.xml文件，mapper.xml文件常见完成后不要随便移动其位置，否则会报类似这样的错误 Invalid bound statement (not found): com.linewell.springboot0525.dao.UserMapper.getUserById <?xml version="1.0" encoding="UTF-8"?> select * from user where id = #{id} ``` org.mybatis.spring.boot mybatis-spring-boot-starter 1.1.1 ``` 测试

数据库test01中的数据

在控制台上打印sql语句 参考：https://blog.csdn.net/qq_16855077/article/details/84975564 在application.yml中配置

logging: level: com.linewell.springboot0525.dao: debug

com.linewell.springboot0525.dao为useMapper.java文件所在的包 或者在application.properties文件中配置也可以，在application.properties中配置如下

logging.level.com.linewell.springboot0525.dao=debug