在golang中迭代接口方法

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我正在尝试迭代接口中的所有方法。我找到了一些例子 - 但我似乎无法让我的例子工作。我正在尝试使用我在其他包中使用的封装结构来执行此操作 - 但对于本例 - 它位于同一个包内。

我正在尝试迭代所有 get 函数（在我的示例中我只有一个 - 但在现实生活中我有几个

我希望我的输出是两行

• “2009/11/10 23:00:00 gettenantuuidqueryinstring”
• "2009/11/10 23:00:00 (tenant_uuid in (uuid_to_bin('8df030a1-a057-4f53-a011-a2b1cff673a1'),uuid_to-bin('9df030a1-a057-4f53-a011-a2b1cff673a) 1')) ”

相反，我得到第一行然后恐慌

• “2009/11/10 23:00:00 gettenantuuidqueryinstring”
• “恐慌：反射：对零值调用reflect.value.call”

这是 on go 演示 https://go.dev/play/p/ysnj46qnift

package main

import (
    "fmt"
    "log"
    "reflect"
    "strings"

    "github.com/google/uuid"
)

func main() {
    pipedTenantUUIDs := "8df030a1-a057-4f53-a011-a2b1cff673a1|8df030a1-a057-4f53-a011-a2b1cff673a1"
    so, responseCode, err := createTenantSearch(pipedTenantUUIDs)
    if err != nil {
        log.Println(err, responseCode)
    }

    t := reflect.TypeOf(&so).Elem()
    v := reflect.ValueOf(&so)

    for i := 0; i < t.NumMethod(); i++ {

        method := t.Method(i)
        if strings.HasPrefix(method.Name, "get") {
            log.Println(method.Name)
            whereVal := v.MethodByName(method.Name).Call(nil)
            log.Println(whereVal[0])
        }
    }

}

// I want my output to be two lines
//  "2009/11/10 23:00:00 getTenantUUIDQueryInString"
//  "2009/11/10 23:00:00 (tenant_uuid IN (UUID_TO_BIN('8df030a1-a057-4f53-a011-a2b1cff673a1'),UUID_TO-BIN('9df030a1-a057-4f53-a011-a2b1cff673a1'))"
//
// instead i get a the first line and then panic
// "2009/11/10 23:00:00 getTenantUUIDQueryInString"
// "panic: reflect: call of reflect.Value.Call on zero Value"
// this is how i have everything set up

type iTenantSearch interface {
    mapTenantUUID(pipedString string) error
    getTenantUUIDQueryInString() string
}

type tenantSearch struct {
    tenantUUID []uuid.UUID
}

func (ts *tenantSearch) mapTenantUUID(pipedString string) error {
    splitString := strings.Split(pipedString, "|")

    for i := 0; i < len(splitString); i++ {
        parsedUUID, err := uuid.Parse(splitString[i])
        if err != nil {
            ts.tenantUUID = []uuid.UUID{}
            return fmt.Errorf("tenant uuid failed to parse: %s", err)
        }
        ts.tenantUUID = append(ts.tenantUUID, parsedUUID)
    }
    return nil
}

func (ts *tenantSearch) getTenantUUIDQueryInString() string {
    inString := ""
    if ts.tenantUUID != nil {
        inString = inString + `(tenant_uuid IN (`
        for i, s := range ts.tenantUUID {
            if i == (len(ts.tenantUUID) - 1) {
                inString = inString + `UUID_TO_BIN('` + s.String() + `')`
            } else {
                inString = inString + `UUID_TO_BIN('` + s.String() + `'),`
            }
        }
        inString = inString + `))`
    }
    return inString
}

func createTenantSearch(tenantUUIDs string) (iTenantSearch, int, error) {
    var tso tenantSearch

    if tenantUUIDs != "" {
        err := tso.mapTenantUUID(tenantUUIDs)
        return nil, 400, err
    }
    return &tso, 200, nil
}

正确答案

感谢 cerise limón，我找到了答案..这是更正后的代码...

1. 修复了创建函数中的逻辑
2. 导出了我的 get 方法
3. 将 v 设置为 itenantsearch： v :=reflect.valueof(&so).elem() – 樱桃柠檬

这是 https://go.dev/play/p/7fG9FcIr6vQ 上的工作代码

package main

import (
    "fmt"
    "log"
    "reflect"
    "strings"

    "github.com/google/uuid"
)

func main() {
    pipedTenantUUIDs := "8df030a1-a057-4f53-a011-a2b1cff673a1|8df030a1-a057-4f53-a011-a2b1cff673a1"
    so, responseCode, err := createTenantSearch(pipedTenantUUIDs)
    if err != nil {
        log.Println(err, responseCode)
    }

    t := reflect.TypeOf(&so).Elem()
    v := reflect.ValueOf(&so).Elem()

    for i := 0; i < t.NumMethod(); i++ {

        method := t.Method(i)
        if strings.HasPrefix(method.Name, "Get") {
            log.Println(method.Name)
            whereVal := v.MethodByName(method.Name).Call(nil)
            log.Println(whereVal[0])
        }
    }

}

type iTenantSearch interface {
    mapTenantUUID(pipedString string) error
    GetTenantUUIDQueryInString() string
}

type tenantSearch struct {
    tenantUUID []uuid.UUID
}

func (ts *tenantSearch) mapTenantUUID(pipedString string) error {
    splitString := strings.Split(pipedString, "|")

    for i := 0; i < len(splitString); i++ {
        parsedUUID, err := uuid.Parse(splitString[i])
        if err != nil {
            ts.tenantUUID = []uuid.UUID{}
            return fmt.Errorf("tenant uuid failed to parse: %s", err)
        }
        ts.tenantUUID = append(ts.tenantUUID, parsedUUID)
    }
    return nil
}

func (ts *tenantSearch) GetTenantUUIDQueryInString() string {
    inString := ""
    if ts.tenantUUID != nil {
        inString = inString + `(tenant_uuid IN (`
        for i, s := range ts.tenantUUID {
            if i == (len(ts.tenantUUID) - 1) {
                inString = inString + `UUID_TO_BIN('` + s.String() + `')`
            } else {
                inString = inString + `UUID_TO_BIN('` + s.String() + `'),`
            }
        }
        inString = inString + `))`
    }
    return inString
}

func createTenantSearch(tenantUUIDs string) (iTenantSearch, int, error) {
    var tso tenantSearch

    err := tso.mapTenantUUID(tenantUUIDs)
    if err != nil {
        return nil, 400, err
    }
    return &tso, 200, nil
}

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