Java开发笔记

多表查询和分页查询

多表

实现复杂关系映射，可以使用@Results注解，@Result注解，@One注解，@Many注解组合完成复杂关系的配置。

（MybatisPLus对多表无变化，以上为Mybatis的注解。）

测试

@Select("select * from t_user")
@Results(
        {
                @Result(column = "id", property = "id"),
                @Result(column = "name",property = "name"),
                @Result(column = "password",property = "password"),
                @Result(column = "id",property = "message",javaType = List.class,
                many = @Many(select="top.rczmm.springboot1.Mapper.MessageMapper.selectById"))
        }
)
List<User> selectAllUsersMessage();

分页

编写配置文件

package top.rczmm.springboot1.configuration;


import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class MybatisPlusConfig {
    @Bean
    public MybatisPlusInterceptor paginationInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        PaginationInnerInterceptor paginationInnerInterceptor = new PaginationInnerInterceptor(DbType.MYSQL);
        interceptor.addInnerInterceptor(paginationInnerInterceptor);
        return interceptor;
    }
}

测试

@GetMapping("findAll")
public IPage findAll() {
    Page<User> page = new Page<>(0,2);
    return userMapper.SelectPage(page);
}