Spring Boot integration mybatis annotations error - spring

Question

When I run the following program I receive the following error. How can I solve it?
Description:
file [E:\program\github\demo\target\classes\com\example\demo\mapper\UserMapper.class] required a single bean, but 4 were found:
- &userMapper: defined in file [E:\program\github\demo\target\classes\com\example\demo\mapper\UserMapper.class]
- systemEnvironment: a programmatically registered singleton - contextParameters: a programmatically registered singleton - contextAttributes: a programmatically registered singleton
Action:
Consider marking one of the beans as #Primary, updating the consumer to accept multiple beans, or using #Qualifier to identify the bean that should be consumed
Disconnected from the target VM, address: '127.0.0.1:58011', transport: 'socket'
Process finished with exit code 1
Here is my Spring Boot config file application.properties:
spring.datasource.driverClassName=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf8&autoReconnect=true&rewriteBatchedStatements=TRUE
spring.datasource.username=root
spring.datasource.password=123456
mybatis.type-aliases-package=com.example.demo.entity
DemoApplication.java -- bootstrap class
#SpringBootApplication
#EnableTransactionManagement
#MapperScan(value="com.example.demo.mapper")
public class DemoApplication {
#Autowired
private UserService userService;
#RequestMapping("add")
public void add(User user) {
userService.addUser(user);
}
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}
entity -- User.java
public class User implements Serializable {
private int userId;
private String username;
public int getUserId() {
return userId;
}
public void setUserId(int userId) {
this.userId = userId;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
#Override
public String toString() {
return "User{" +
"userId=" + userId +
", username='" + username + '\'' +
'}';
}
}
Service -- UserService.java
public interface UserService {
void addUser(User user);
}
Service implementation -- UserServiceImpl.java
#Service
public class UserServiceImpl implements UserService {
#Autowired
private UserMapper userMapper;
#Override
#Transactional
public void addUser(User user) {
userMapper.insert(user);
}
}
Mybatis interface -- UserMapper.java
#Mapper
public interface UserMapper {
#Insert(
value = "insert into user values(#{user.userId},#{user.username})"
)
void insert(User user);
}