Go 系列教程 —— 33. golang中struct、json、map互相轉化

結構體生成Json

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package main   import (      "encoding/json"      "fmt" )   type IT struct {      Company string `json: "-" ` //此字段不會輸出到屏幕      //Company  string   `json:"company"`       這樣打印輸出別名首字母就會小寫(二次編碼)      Subjects []string `json: "subjects" ` //二次編碼      IsOk     bool     `json: ",string" `      Price    float64  `json: ",string" ` }   func main() {      //定義一個結構體變量，同時初始化      s := IT{ "itcast" , []string{ "Golang" , "PHP" , "Java" , "C++" }, true, 666.666}        //編碼，根據內容生成json文本      //buf, err := json.Marshal(s)      //buf =  {"subjects":["Golang","PHP","Java","C++"],"IsOk":"true","Price":"666.666"}      buf, err := json.MarshalIndent(s, "" , "    " ) //格式化編碼      if err != nil {          fmt.Println( "err = " , err)          return      }        fmt.Println( "buf = " , string(buf)) }

　　

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//結果 buf =  {          "subjects" : [   //首字母小寫                 "Golang" ,                  "PHP" ,                  "Java" ,                  "C++"          ],         "IsOk" : "true" ,   //string類型         "Price" : "666.666" }

　　Json轉成結構體

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package main   import (      "encoding/json"      "fmt" )   type IT struct {      Address   string   `json: "address" `      Languages []string `json: "languages" ` //二次編碼      Status    bool     `json: "isok" `      Price     float64  `json: "price" ` }   func main() {        jsonBuf := `      {      "address" : "北京" ,      "languages" : [          "Golang" ,          "PHP" ,          "Java" ,          "Python"      ],      "status" : true,      "price" : 666.666 }`        var tmp IT                                   //定義一個結構體變量      err := json.Unmarshal([]byte(jsonBuf), &tmp) //第二個參數要地址傳遞      if err != nil {          fmt.Println( "err = " , err)          return      }      //fmt.Println("tmp = ", tmp)      fmt.Printf( "tmp = %+v\n" , tmp)        type IT2 struct {          Subjects []string `json: "languages" ` //二次編碼      }        var tmp2 IT2      err = json.Unmarshal([]byte(jsonBuf), &tmp2) //第二個參數要地址傳遞      if err != nil {          fmt.Println( "err = " , err)          return      }      fmt.Printf( "tmp2 = %+v\n" , tmp2)   }

　　

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1 2	tmp = {Address:北京 Languages:[Golang PHP Java Python] Status:false Price:666.666} tmp2 = {Subjects:[Golang PHP Java Python]}

　　Map生成Json

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package main   import (      "encoding/json"      "fmt" )   func main() {      //建立一個map      m := make( map [string] interface {}, 4) //由於類型多，能夠用interface空接口      m[ "address" ] = "北京"      m[ "languages" ] = []string{ "Golang" , "PHP" , "Java" , "Python" }      m[ "status" ] = true      m[ "price" ] = 666.666        //編碼成json      //result, err := json.Marshal(m)      //result =  {"address":"北京","languages":["Golang","PHP","Java","Python"],"price":666.666,"status":true}      result, err := json.MarshalIndent(m, "" , "    " )      if err != nil {          fmt.Println( "err = " , err)          return      }      fmt.Println( "result = " , string(result)) }

　　

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result =  {          "address" : "北京" ,          "languages" : [                  "Golang" ,                  "PHP" ,                  "Java" ,                  "Python"          ],          "price" : 666.666,          "status" : true }

　　Json轉化爲Map

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package main   import (      "encoding/json"      "fmt" )   func main() {      jsonBuf := `      {      "company" : "itcast" ,      "subjects" : [          "Go" ,          "C++" ,          "Python" ,          "Test"      ],      "isok" : true,      "price" : 666.666 }`        //建立一個map      m := make( map [string] interface {}, 4)        err := json.Unmarshal([]byte(jsonBuf), &m) //第二個參數要地址傳遞      if err != nil {          fmt.Println( "err = " , err)          return      }      fmt.Printf( "m = %+v\n" , m)        //    var str string      //    str = string(m["company"]) //err， 沒法轉換      //    fmt.Println("str = ", str)        var str string        //類型斷言, 值，它是value類型      for key, value := range m {          //fmt.Printf("%v ============> %v\n", key, value)          switch data := value.( type ) {          case string:              str = data              fmt.Printf( "map[%s]的值類型爲string, value = %s\n" , key, str)          case bool:              fmt.Printf( "map[%s]的值類型爲bool, value = %v\n" , key, data)          case float64:              fmt.Printf( "map[%s]的值類型爲float64, value = %f\n" , key, data)          case []string:              fmt.Printf( "map[%s]的值類型爲[]string, value = %v\n" , key, data)          case [] interface {}:              fmt.Printf( "map[%s]的值類型爲[]interface, value = %v\n" , key, data)          }        }   }

　　

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map [address]的值類型爲string, value = 北京 map [Languages]的值類型爲[] interface , value = [Golang PHP Java Python] map [Status]的值類型爲bool, value = true map [price]的值類型爲float64, value = 666.666000

　　[]interface{}轉json

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package main    import (      "encoding/json"      "fmt" ) func main(){      var s [] interface {}      s = append(s,5)      s = append(s,[]string{ "Golang" , "PHP" , "Java" , "Python" })      s = append(s, map [string]string{ "hello" : "world" })      result, err := json.MarshalIndent(s, "" , "    " )      if err != nil {          fmt.Println( "err = " , err)          return      }      fmt.Println( "result = " , string(result)) }

　　

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result =  [      5,      [          "Golang" ,          "PHP" ,          "Java" ,          "Python"      ],      {          "hello" : "world"      } ]