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EmitMapper的使用小结

2024-07-11 08:27:33   212人阅读

最近公司开发项目前端使用一个js框架，后端使用ef，js前台读取的json采用实体的dto来进行生成。

在网上看到了EmitMapper相对其他映射框架处理速度可以更快，就拿来用了。下面是代码中常用的几个块。

1.普通的映射。

    public class UserInfo    {        public int id { get; set; }        public string name { get; set; }        public string address { get; set; }    }    public class UserInfoDTO    {                public string name { get; set; }        public string address { get; set; }    }    var mapper = ObjectMapperManager.DefaultInstance.GetMapper<UserInfo, UserInfoDTO>();
    UserInfoDTO userdto = mapper.Map(user);

2.有外键关联，需要映射出外键所带名字

    public class UserInfo    {        public int id { get; set; }        public string name { get; set; }        public string address { get; set; }        public Teacher teacher { get; set; }    }    public class Teacher    {        public int id { get; set; }        public string name { get; set; }    }    public class UserInfoDTO    {        public int id { get; set; }        public string name { get; set; }        public string teacher { get; set; }    }    var user = new UserInfo {                 id = 12,                 name = "张三",                 address = "北京",                teacher = new Teacher {                     id = 11,                     name = "王五"                 }            };     var mapper = ObjectMapperManager.DefaultInstance.GetMapper<UserInfo, UserInfoDTO>(                new DefaultMapConfig()                .ConvertUsing<Teacher, string>(t => t.name)                );     UserInfoDTO userdto = mapper.Map(user);

3.两个实体之间名字不一致，需要映射。

    public class UserInfo    {        public int id { get; set; }        public string name { get; set; }        public string address { get; set; }    }    public class UserInfoDTO    {        public int id { get; set; }        public string name { get; set; }        public string userAddress { get; set; }    }    var mapper = ObjectMapperManager.DefaultInstance.GetMapper<UserInfo, UserInfoDTO>(                new DefaultMapConfig()                .MatchMembers((x, y) =>                {                    if (x == "address" && y == "userAddress")                    {                        return true;                    }                    return x == y;                })                );    UserInfoDTO userdto = mapper.Map(user);

4.需要对某一个字段进行特殊处理

    public class UserInfo    {        public int id { get; set; }        public string name { get; set; }        public string address { get; set; }    }    public class UserInfoDTO    {        public string id { get; set; }        public string name { get; set; }        public string userAddress { get; set; }        public string userJson { get; set; }    }    var user = new UserInfo {                 id = 12,                 name = "张三",                 address = "北京"            };    var mapper = ObjectMapperManager.DefaultInstance.GetMapper<UserInfo, UserInfoDTO>(                new DefaultMapConfig()                .PostProcess<UserInfoDTO>((value, state) =>                {                    //在id编号前加上今年的年份                    value.id = DateTime.Now.ToString("yyyy") + value.id;                    //实体的json格式                    value.userJson = "{\"id\":\"" + value.id + "\",\"name\":\"" + value.name + "\"}";                    return value;                })            );     UserInfoDTO userdto = mapper.Map(user);

5.忽略掉某个字段的映射

    public class UserInfo    {        public int id { get; set; }        public string name { get; set; }        public string address { get; set; }    }    public class UserInfoDTO    {        public string id { get; set; }        public string name { get; set; }        public string address { get; set; }    }    var user = new UserInfo {                 id = 12,                 name = "张三",                 address = "北京"            };    var mapper = ObjectMapperManager.DefaultInstance.GetMapper<UserInfo, UserInfoDTO>(                new DefaultMapConfig()                .IgnoreMembers<UserInfo, UserInfoDTO>(new string[] { "name" })            );    UserInfoDTO userdto = mapper.Map(user);

6.给空元素赋默认值

    public class UserInfo    {        public int id { get; set; }        public string name { get; set; }        public string address { get; set; }        public DateTime? godate { get; set; }    }    public class UserInfoDTO    {        public string id { get; set; }        public string name { get; set; }        public string address { get; set; }        public DateTime godate { get; set; }    }    var user = new UserInfo {                 id = 12,                 name = "张三",                 address = null,                godate = null            };    var mapper = ObjectMapperManager.DefaultInstance.GetMapper<UserInfo, UserInfoDTO>(                new DefaultMapConfig()                //如果日期为空设置为当前时间                .NullSubstitution<DateTime?, DateTime>((value) => DateTime.Now)                //如果string类型为null赋值为“”                .NullSubstitution<string, string>((value) => "")            );    UserInfoDTO userdto = mapper.Map(user);

常用的就上面几点，对于更深入的。有待以后研究。。。。。


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