ASP.NET Core 2.2 WebApi 系列【六】泛型仓储模式

为什么要使用泛型仓储？好处是？

前两章在autofac注入的时候，用的user类作为例子，写了增删改查四个接口，也就是仓储的grud。

        当我们再添加一个实体（比如student）时，studentrepository跟userrepository代码几乎一样的代码，重复量很大，为了减少冗余、提高工作效率，使用泛型仓储最好不过了

好处：

减少代码冗余

提高了开发人员的工作效率

提高对数据库访问的维护

一、泛型仓储接口和泛型仓储实现类

泛型仓储接口

在类库项目上右键->添加->新建文件夹，命名为repository，存放泛型仓储类。在repository文件夹下面新建 泛型仓储接口类：irepository，如下：

using system;
using system.collections.generic;
using system.linq;
using system.linq.expressions;
using netcorewebapi.repository.dto;

namespace netcorewebapi.repository.repository
{
    public interface irepository<t> where t : class
    {
        /// <summary>
        /// 添加实体(单个)
        /// </summary>
        /// <param name="entity">实体对象</param>
        int add(t entity);

        /// <summary>
        /// 批量插入实体(多个)
        /// </summary>
        /// <param name="list">实体列表</param>
        int addrange(list<t> list);

        /// <summary>
        /// 删除实体(单个)
        /// </summary>
        /// <param name="entity"></param>
        int remove(t entity);

        /// <summary>
        /// 批量删除实体(多个)
        /// </summary>
        /// <param name="list">实体列表</param>
        int removerange(list<t> list);
        /// <summary>
        /// 获取所有 
        /// </summary>
        /// <returns></returns>
        iqueryable<t> getall();
        /// <summary>
        /// 分页条件查询
        /// </summary>
        /// <typeparam name="tkey">排序类型</typeparam>
        /// <param name="pageindex">当前页</param>
        /// <param name="pagesize">每页大小</param>
        /// <param name="predicate">条件表达式</param>
        /// <param name="isasc">是否升序排列</param>
        /// <param name="keyselector">排序表达式</param>
        /// <returns></returns>
        page<t> searchfor<tkey>(int pageindex, int pagesize, expression<func<t, bool>> predicate,
            bool isasc, expression<func<t, tkey>> keyselector);
        /// <summary>
        /// 获取实体（主键）
        /// </summary>
        /// <param name="id">主键id</param>
        /// <returns></returns>
        t getmodelbyid(object id);
        /// <summary>
        /// 获取实体（条件）
        /// </summary>
        /// <param name="predicate">条件表达式</param>
        /// <returns></returns>
        t getmodel(expression<func<t, bool>> predicate);
        /// <summary>
        /// 查询记录数
        /// </summary>
        /// <param name="predicate">条件表达式</param>
        /// <returns>记录数</returns>
        int count(expression<func<t, bool>> predicate);
        /// <summary>
        /// 是否存在
        /// </summary>
        /// <param name="anylambda">查询表达式</param>
        /// <returns>布尔值</returns>
        bool exist(expression<func<t, bool>> anylambda);
    }
}

泛型仓储实现类

在repository文件夹下面新建 泛型仓储实现类：repository，并继承irepository，如下：

using system;
using system.collections.generic;
using system.linq;
using system.linq.expressions;
using microsoft.entityframeworkcore;
using netcorewebapi.model;
using netcorewebapi.repository.dto;

namespace netcorewebapi.repository.repository
{
    public class repository<t> : irepository<t> where t : class
    {
        private readonly mydbcontext _dbcontext;
        private dbset<t> _entity;

        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="dbcontext"></param>
        public repository(mydbcontext dbcontext)
        {
            _dbcontext = dbcontext;
        }
        private dbset<t> entity => _entity ?? (_entity = _dbcontext.set<t>());
        /// <summary>
        /// 添加实体(单个)
        /// </summary>
        /// <param name="entity">实体对象</param>
        public int add(t entity)
        {
            entity.add(entity);
            return _dbcontext.savechanges();
        }
        /// <summary>
        /// 批量插入实体(多个)
        /// </summary>
        /// <param name="list">实体列表</param>
        public int addrange(list<t> list)
        {
            entity.addrange(list);
            return _dbcontext.savechanges();
        }

        /// <summary>
        /// 删除实体(单个)
        /// </summary>
        /// <param name="entity"></param>
        public int remove(t entity)
        {
            entity.remove(entity);
            return _dbcontext.savechanges();
        }
        /// <summary>
        /// 批量删除实体(多个)
        /// </summary>
        /// <param name="list">实体列表</param>
        public int removerange(list<t> list)
        {
            entity.removerange(list);
            return _dbcontext.savechanges();
        }
        /// <summary>
        /// 获取所有
        /// </summary>
        /// <returns></returns>
        public iqueryable<t> getall()
        {
            return entity.asqueryable().asnotracking();
        }
        /// <summary>
        /// 条件查询
        /// </summary>
        /// <typeparam name="tkey">排序类型</typeparam>
        /// <param name="pageindex">当前页</param>
        /// <param name="pagesize">每页大小</param>
        /// <param name="isasc">是否升序排列</param>
        /// <param name="predicate">条件表达式</param>
        /// <param name="keyselector">排序表达式</param>
        /// <returns></returns>
        public page<t> searchfor<tkey>(int pageindex, int pagesize, expression<func<t, bool>> predicate, bool isasc,
            expression<func<t, tkey>> keyselector)
        {
            if (pageindex <= 0 || pagesize <= 0) throw new exception("pageindex或pagesize不能小于等于0");
            var page = new page<t> { pageindex = pageindex, pagesize = pagesize };
            var skip = (pageindex - 1) * pagesize;
            var able = entity.asqueryable().asnotracking();
            if (predicate == null)
            {
                var count = entity.count();
                var query = isasc
                    ? able.orderby(keyselector).skip(skip).take(pagesize)
                    : able.orderbydescending(keyselector).skip(skip).take(pagesize);
                page.totalrows = count;
                page.lslist = query.tolist();
                page.totalpages = page.totalrows / pagesize;
                if (page.totalrows % pagesize != 0) page.totalpages++;
            }
            else
            {
                var queryable = able.where(predicate);
                var count = queryable.count();
                var query = isasc
                    ? queryable.orderby(keyselector).skip(skip).take(pagesize)
                    : queryable.orderbydescending(keyselector).skip(skip).take(pagesize);
                page.totalrows = count;
                page.lslist = query.tolist();
                page.totalpages = page.totalrows / pagesize;
                if (page.totalrows % pagesize != 0) page.totalpages++;
            }
            return page;
        }
        /// <summary>
        /// 获取实体
        /// </summary>
        /// <param name="id">主键id</param>
        /// <returns></returns>
        public t getmodelbyid(object id)
        {
            return entity.find(id);
        }

        /// <summary>
        /// 获取实体（条件）
        /// </summary>
        /// <param name="predicate">条件表达式</param>
        /// <returns></returns>
        public t getmodel(expression<func<t, bool>> predicate)
        {
            return entity.firstordefault(predicate);
        }
        /// <summary>
        /// 查询记录数
        /// </summary>
        /// <param name="predicate"></param>
        /// <returns></returns>
        public int count(expression<func<t, bool>> predicate)
        {
            return predicate != null ? entity.where(predicate).count() : entity.count();
        }
        /// <summary>
        /// 是否存在
        /// </summary>
        /// <param name="anylambda"></param>
        /// <returns></returns>
        public bool exist(expression<func<t, bool>> anylambda)
        {
            return entity.any(anylambda);
        }
    }
}

分页page类

using system.collections.generic;

namespace netcorewebapi.repository.dto
{
    public class page<t>
    {
        /// <summary>
        /// 当前页
        /// </summary>
        public int pageindex { get; set; }
        /// <summary>
        /// 总页数
        /// </summary>
        public int totalpages { get; set; }
        /// <summary>
        /// 集合总数
        /// </summary>
        public int totalrows { get; set; }
        /// <summary>
        /// 每页项数
        /// </summary>
        public int pagesize { get; set; }
        /// <summary>
        /// 集合
        /// </summary>
        public ilist<t> lslist { get; set; }
    }
}

二、仓储的泛型的依赖注入。

修改startup.cs启动类中configureservices方法

        public static icontainer applicationcontainer { get; set; }
        /// <summary>
        /// //负责注入服务
        /// </summary>
        /// <param name="services"></param>
        /// <returns></returns>
        public iserviceprovider configureservices(iservicecollection services)
        {
            //获取数据库连接字符串
            var connectionstr = configuration.getconnectionstring("sqlserver");
            services.adddbcontext<mydbcontext>
                (options => options.usesqlserver(connectionstr,
                    e => e.migrationsassembly("netcorewebapi.model")));
            services.addmvc().setcompatibilityversion(compatibilityversion.version_2_2);
            //初始化容器
            var builder = new containerbuilder();
            //管道寄居
            builder.populate(services);
            //注册业务
            builder.registerassemblytypes(assembly.load("netcorewebapi.repository"), assembly.load("netcorewebapi.repository"))
                .where(t => t.name.endswith("repository"))
                .asimplementedinterfaces();
            //注册仓储，所有irepository接口到repository的映射
            builder.registergeneric(typeof(repository<>))
                //instanceperdependency：默认模式，每次调用，都会重新实例化对象；每次请求都创建一个新的对象；
                .as(typeof(irepository<>)).instanceperdependency();
            //构造
            applicationcontainer = builder.build();
            //将autofac反馈到管道中
            return new autofacserviceprovider(applicationcontainer);
        }

 

 三、测试

修改业务层---userrepository

给泛型类指定thuser，红色字体是主要更改部分。

using system.collections.generic;
using system.linq;
using netcorewebapi.model.models;
using netcorewebapi.repository.interface;
using netcorewebapi.repository.repository;

namespace netcorewebapi.repository.implement
{
    /// <summary>
    /// 业务处理
    /// </summary>
    public class userrepository:iuserrepository
    {
        private readonly irepository<tbuser> _userrepository;

        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="userrepository"></param>
        public userrepository(irepository<tbuser> userrepository)
        {
            _userrepository = userrepository;
        }
        /// <summary>
        /// 添加用户
        /// </summary>
        /// <param name="entity"></param>
        /// <returns></returns>
        public int add(tbuser entity)
        {
            return _userrepository.add(entity);
        }
        /// <summary>
        /// 删除用户
        /// </summary>
        /// <param name="entity"></param>
        /// <returns></returns>
        public int remove(tbuser entity)
        {
            return _userrepository.remove(entity);
        }
        /// <summary>
        /// 查询用户
        /// </summary>
        /// <returns></returns>
        public ilist<tbuser> getall()
        {
            return _userrepository.getall().tolist();
        }
    }
}

运行项目执行接口，可以看到跟之前一样 

如果有其他实体只需要改变传入的t就可以了，不需要再重新创建tentityrepository