如何在Golang中使用reflect实现对象字段复制_Golang reflect对象字段复制方法汇总

func CopyFields(dst, src interface{}) error {
    dstVal := reflect.ValueOf(dst)
    srcVal := reflect.ValueOf(src)

    // 确保传入的是指针，并解引用
    if dstVal.Kind() != reflect.Ptr || !dstVal.Elem().CanSet() {
        return fmt.Errorf("destination must be a settable pointer")
    }
    if srcVal.Kind() == reflect.Ptr {
        srcVal = srcVal.Elem()
    }

    dstVal = dstVal.Elem()
    srcVal = srcVal

    dstType := dstVal.Type()
    srcType := srcVal.Type()

    for i := 0; i < dstVal.NumField(); i++ {
        df := dstVal.Field(i)
        dfName := dstType.Field(i).Name

        // 查找源对象中是否有同名字段
        sf, exists := srcType.FieldByName(dfName)
        if !exists {
            continue
        }

        srcField := srcVal.Field(sf.Index[0])
        if !df.CanSet() {
            continue
        }

        // 类型必须匹配才能赋值
        if df.Type() == srcField.Type() {
            df.Set(srcField)
        }
    }
    return nil
}

type A struct {
    Name string
    Age  int
}

type B struct {
    Name string
    Age  int
    Addr string
}

a := A{Name: "Tom", Age: 25}
var b B
CopyFields(&b, &a) // b.Name = "Tom", b.Age = 25

type A struct {
    FullName string `copy:"Name"`
    Age      int    `copy:"Age"`
}

type B struct {
    Name string
    Age  int
}

sf, exists := srcType.FieldByName(dfName)
if !exists {
    // 尝试通过标签查找
    for j := 0; j < srcVal.NumField(); j++ {
        field := srcType.Field(j)
        tag := field.Tag.Get("copy")
        if tag == dfName {
            srcField := srcVal.Field(j)
            if df.Type() == srcField.Type() && df.CanSet() {
                df.Set(srcField)
            }
            break
        }
    }
}

import "github.com/jinzhu/copier"

copier.Copy(&b, &a) // 自动按字段名复制