創(chuàng)建項(xiàng)目：
image.png
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創(chuàng)建測(cè)試表
在數(shù)據(jù)庫(kù)中：創(chuàng)建測(cè)試表
create table user
(
id bigint not null AUTO_INCREMENT comment '主鍵' primary key,
age int null comment '年齡',
password varchar(32) null comment '密碼',
sex int null comment '性別',
username varchar(32) null comment '用戶名'
);
配置數(shù)據(jù)源
修改配置文件：配置數(shù)據(jù)源：application.yml
spring:
#profiles: dev
datasource:
url: jdbc:mysql://localhost:3306/helloworld?useUnicode=true&characterEncoding=utf8&serverTimezone=UTC
username: root
password: root
driver-class-name: com.mysql.cj.jdbc.Driver
編寫代碼
創(chuàng)建實(shí)體類 User.java
public class User {
private Long id;
private String username;
private String password;
private Integer age;
private Integer sex;
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public Integer getSex() {
return sex;
}
public void setSex(Integer sex) {
this.sex = sex;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
}
創(chuàng)建訪問(wèn)接口 UserMapper ( 注意需要用 @Mapper注解)
import com.example.demo4mybatis.entity.User;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;
import java.util.List;
@Mapper
public interface UserMapper {
@Select("select * from user")
List<User> selectAll();
@Select("select * from user where USERNAME= #{user_name} ")
User selectByName(@Param("user_name") String userName);
}
測(cè)試代碼
@Autowired
private UserMapper userMapper;
@Test
public void test() {
List<User> list = userMapper.selectAll();
System.out.println("--" + list.size());
User user = userMapper.selectByName("張三豐");
System.out.println("--" + user);
}
