Springboot+MybatisPlus实现增删改查和分页

项目目录

添加依赖:pom.xml

    
        org.springframework.boot
        spring-boot-starter-web
    
    
        org.springframework.boot
        spring-boot-starter-test
        test
    
    
    
        mysql
        mysql-connector-java
    
    
    
        org.projectlombok
        lombok
    
    
    
        com.baomidou
        mybatis-plus-boot-starter
        3.0.5
    
    
    
        org.apache.velocity
        velocity-engine-core
        2.0
    
    
    
        com.alibaba
        druid
        1.0.29
    

配置文件application.properties

# mysql 5 驱动不同  com.mysql.jdbc.Driver
# mysql 8 驱动不同 com.mysql.cj.jdbc.Driver . 需要增加时区的配置 serverTimezone=GMT%2B8
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.url=jdbc:mysql://localhost:3306/mybatis_plus?useSSL=false&useUnicode=true&characterEncoding=utf-8&serverTimezone=GMT%2B8
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

创建一个MybatisPlus分页的拦截器MybatisPlusConfig，如果不创建，MybatisPlus就不会在sql上增加分页的语句

@Configuration
@ConditionalOnClass(value = {PaginationInterceptor.class})
public class MybatisPlusConfig {
    @Bean
    public PaginationInterceptor paginationInterceptor() {
        PaginationInterceptor paginationInterceptor = new PaginationInterceptor();
        return paginationInterceptor;
    }
}

建立实体类User

@TableName("user")
public class User {
    private Long id;
    private String name;
    private Integer age;
    private String email;
    //getter and setter
}

mapper层，建立UserMapper继承baseMapper

@Repository//代表持久层
@Mapper
public interface UserMapper extends baseMapper {}

修改启动类MybatisPlusApplication，添加@MapperScan注解

@MapperScan("com.wyx.mapper")
@SpringBootApplication
public class MybatisPlusApplication {

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

service层

public interface UserService {
    //增
    Integer add(User user);

    //删
    Integer delete(Long id);

    //改
    Integer update(User user);

    //查
    User select(Long id);

    //分页
    public IPage selectPage(long page, long size);
}

建立serviceImpl

@Service
public class UserServiceImpl implements UserService {
    @Autowired
    UserMapper userMapper;
    
    @Override
    public Integer add(User user) {
        return userMapper.insert(user);
    }

    @Override
    public Integer delete(Long id) {
        return userMapper.deleteById(id);
    }

    @Override
    public Integer update(User user) {
        return userMapper.updateById(user);
    }

    @Override
    public User select(Long id) {
        return userMapper.selectById(id);
    }

    @Override
    public IPage selectPage(long page, long size) {
        IPage iPage = userMapper.selectPage(new Page<>(page,size),null);
        return iPage;
    }
}

controller层

@Controller
@RequestMapping("/wyx")
public class UserController {
    @Autowired
    UserService userService;
    
    @RequestMapping("/add")
    @ResponseBody
    public Integer addUser(@RequestBody User user){
        return userService.add(user);
    }

    
    @RequestMapping("/delete")
    @ResponseBody
    public Integer deleteUser(@RequestBody User user){
        return userService.delete(user.getId());
    }

    
    @RequestMapping("/update")
    @ResponseBody
    public Integer updateUser(@RequestBody User user){
        return userService.update(user);
    }

    
    @RequestMapping("/select")
    @ResponseBody
    public User selectUser(@RequestBody User user){
        return userService.select(user.getId());
    }

    
    @RequestMapping("/page")
    @ResponseBody
    public List getUserPage(@Param("page") long page){
        long size = 5;
        IPage ipage =userService.selectPage(page,size);
        return ipage.getRecords();
    }
}

调用apipost接口测试

查
http://127.0.0.1:8080/wyx/select
{
	"id": 2
}

增
http://127.0.0.1:8080/wyx/add
{
    "name": "詹姆斯",
    "age": 36,
    "email": "222222222@qq.com"
}

改
http://127.0.0.1:8080/wyx/update
{
    "id": 3,
    "name": "库里",
    "age": 3,
    "email": "3333333@qq.com"
}

删
http://127.0.0.1:8080/wyx/delete
{
    "id": 5
}

分页
http://127.0.0.1:8080/wyx/page
page   2

分页:

在控制台打印日志:执行的sql语句

在application.properties中加

logging.level.com.wyx.mapper=debug
mybatis.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl

创建两张有关联的表

UserMapper新增一个接口

@Mapper
public interface UserMapper extends baseMapper {
    //联表查询用户和他们的所属部门
    List selectByUid(@Param("uid") Long uid);
}

在resources目录下新建mapper目录,创建UserMapper.xml并编写sql语句

    
        select u.name, u.age, d.departmentName
        from user u
        left join department d
        on u.department_id = d.did
        where u.uid =#{uid}
    

UserService新增接口

//联表查询
List selectByUid(Long uid);

实现类UserServiceImpl新增重写方法

@Override
public List selectByUid(Long uid) {
    return userMapper.selectByUid(uid);
}

UserController新增一个方法

@RequestMapping("/union")
@ResponseBody
public List selectByUid(@RequestBody User user){
    return userService.selectByUid(user.getUid());
}