我如何在Go中动态创建JSON结构?

huangapple go评论109阅读模式
英文:

How can I create a JSON structure dynamically from Go?

问题

就像序列化JSON一样。

我的当前代码不起作用,我认为这可能与_Map、_String等不是公共的有关。

// vim:ft=go:ts=2

package main

import "json"
import "fmt"
import vector "container/vector"

func main() {
  groceries := vector.New(0);
  groceries.Push(&json._String{s:"Eggs"});
  groceries.Push(&json._String{s:"Bread"});
  groceries.Push(&json._String{s:"Milk"});
  var tree json.Json = &json._Map{m:map[string]json.Json{
    "hello": &json._String{s:"world"},
    "groceries": &json._Array{a:groceries}
  }};
  fmt.Printf(json.JsonToString(tree));
}
英文:

As in, serializing JSON.

My current code doesn't work, and I think it must have something to do with the fact that _Map, _String, etc. are not public.

// vim:ft=go:ts=2

package main

import "json"
import "fmt"
import vector "container/vector"

func main() {
  groceries := vector.New(0);
  groceries.Push(&json._String{s:"Eggs"});
  groceries.Push(&json._String{s:"Bread"});
  groceries.Push(&json._String{s:"Milk"});
  var tree json.Json = &json._Map{m:map[string]json.Json{
    "hello": &json._String{s:"world"},
    "groceries": &json._Array{a:groceries}
  }};
  fmt.Printf(json.JsonToString(tree));
}

答案1

得分: 1

请查看$GOROOT/src/pkg/json/generic_test.go中的TestJsonMap函数,它似乎做了与您想要的类似的事情。相关的代码如下:

var jsontests = []string{
    `null`,
    `true`,
    `false`,
    `"abc"` // , etc.
}
values := make(map[string]Json);
mapstr := "{";
for i := 0; i < len(jsontests); i++ {
    val, ok, errtok := StringToJson(jsontests[i]);
    if !ok {
        t.Errorf("StringToJson(%#q) => error near %v", jsontests[i], errtok)
    }
    if i > 0 {
        mapstr += ",";
    }
    values[jsontests[i]] = val;
    mapstr += Quote(jsontests[i]);
    mapstr += ":";
    mapstr += JsonToString(val);
}
mapstr += "}";

mapv, ok, errtok := StringToJson(mapstr);

您想要将值"world"推送到名称"hello",并将["Eggs","Bread","Milk"]推送到"Groceries"。请尝试以下代码:

var values = make(map[string]string);
values["hello"] = `"world"`;
values["groceries"] = `["Eggs","Bread","Milk"]`;

mapstr := "{";
needcomma := false;
for key,val := range values {
    jsonval, ok, errtok := json.StringToJson(val);
    // 检查错误

    // 添加逗号
    if needcomma == true {
        mapstr += ",";
    } else {
        needcomma = true;
    } 
    
    mapstr += json.Quote(key);
    mapstr += ":";
    mapstr += json.JsonToString(jsonval);
}
mapstr += "}";
mapv, ok, errtok := json.StringToJson(mapstr);
英文:

Have a look at the TestJsonMap function in $GOROOT/src/pkg/json/generic_test.go, it seems to do something similar to what you want. The relevant code is

var jsontests = []string{
    `null`,
    `true`,
    `false`,
    `"abc"` // , etc.
}
values := make(map[string]Json);
mapstr := "{";
for i := 0; i < len(jsontests); i++ {
    val, ok, errtok := StringToJson(jsontests[i]);
    if !ok {
        t.Errorf("StringToJson(%#q) => error near %v", jsontests[i], errtok)
    }
    if i > 0 {
        mapstr += ","
    }
    values[jsontests[i]] = val;
    mapstr += Quote(jsontests[i]);
    mapstr += ":";
    mapstr += JsonToString(val);
}
mapstr += "}";

mapv, ok, errtok := StringToJson(mapstr);

You want to push the value "world" onto the name "hello" and ["Eggs","Bread","Milk"] onto "Groceries". Try

var values = make(map[string]string);
values["hello"] = `"world"`;
values["groceries"] = `["Eggs","Bread","Milk"]`;

mapstr := "{";
needcomma := false;
for key,val := range values {
    jsonval, ok, errtok := json.StringToJson(val);
    // Check errors

    // Add a comma
    if needcomma == true {
        mapstr += ",";
    } else {
        needcomma = true;
    } 
    
    mapstr += json.Quote(key);
    mapstr += ":";
    mapstr += json.JsonToString(jsonval);
}
mapstr += "}";
mapv, ok, errtok := json.StringToJson(mapstr);

答案2

得分: 1

这是一个实现Json接口的基本框架:

package main
import {"json"; "fmt"; "os";}
type MyTest struct { MyMap map[string]string;}
func (t * MyTest) Kind()    int       { return json.MapKind  } 
func (t * MyTest) Len()     int       { return len (t.MyMap) }
func (t * MyTest) Number()  float64   { return 0 }
func (t * MyTest) Bool()    bool      { return false }
func (t * MyTest) Elem(int) json.Json { return json.Null }
func (t * MyTest) String() (s string) {
    s = "{"; 
    count := 0;
    for key, value := range t.MyMap {
        s += json.Quote(key) + ":" + json.Quote(value);
        count++;
        if (count < len (t.MyMap)) {
            s += ",";
        }
    }
    s += "}";
    return;
}
func (t * MyTest) Get(s string) json.Json {
    j, ok, errtok := json.StringToJson (t.MyMap
展开收缩
); if ! ok { fmt.Printf ("Fail at %s\n", errtok); os.Exit (1); } return j; }

这是一些测试代码:

func main () {
    var megaburger = new (MyTest);
    megaburger.MyMap = make(map[string]string);
    megaburger.MyMap["frog"] = "toad";
    megaburger.MyMap["captain"] = "kirk";
    megaburger.MyMap["laser"] = "phaser";
    fmt.Println (megaburger.Kind());
    fmt.Println (megaburger.Len());
    fmt.Println (json.JsonToString (megaburger));
}

通过定义Json包的接口,将JsonToString方法添加到MyTest类型上。显然,目前它还没有做任何有趣的事情,但是你可以为你的特定数据结构定义类似的东西,以便从你的结构中创建任何你喜欢的JSON。在库源代码文件generic.go中,有一个很好的使用所谓的_Null进行嵌入的示例。

英文:

Here is the bare bones of an implementation of the interface for Json:

package main
import {"json"; "fmt"; "os";}
type MyTest struct { MyMap map[string]string;}
func (t * MyTest) Kind()    int       { return json.MapKind  } 
func (t * MyTest) Len()     int       { return len (t.MyMap) }
func (t * MyTest) Number()  float64   { return 0 }
func (t * MyTest) Bool()    bool      { return false }
func (t * MyTest) Elem(int) json.Json { return json.Null }
func (t * MyTest) String() (s string) {
    s = "{"; 
    count := 0;
    for key, value := range t.MyMap {
        s += json.Quote(key) + ":" + json.Quote(value);
        count++;
        if (count < len (t.MyMap)) {
            s += ",";
        }
    }
    s += "}";
    return;
}
func (t * MyTest) Get(s string) json.Json {
    j, ok, errtok := json.StringToJson (t.MyMap
展开收缩
); if ! ok { fmt.Printf ("Fail at %s\n", errtok); os.Exit (1); } return j; }

Here is some testing code:

func main () {
    var megaburger = new (MyTest);
    megaburger.MyMap = make(map[string]string);
    megaburger.MyMap["frog"] = "toad";
    megaburger.MyMap["captain"] = "kirk";
    megaburger.MyMap["laser"] = "phaser";
    fmt.Println (megaburger.Kind());
    fmt.Println (megaburger.Len());
    fmt.Println (json.JsonToString (megaburger));
}

This puts a JsonToString method onto the type MyTest by defining the interface for the Json package. Clearly this doesn't do anything interesting yet, but you could define various things like these for your particular data structure in order to have a "JSON-izer" which created whatever JSON you liked from your structure. There is a nice example of how to do embedding using something called _Null in the library source code file generic.go.

答案3

得分: 1

这看起来很有前途。

//import "github.com/Jeffail/gabs"

jsonObj := gabs.New()
// 或者 gabs.Consume(jsonObject) 来处理一个已存在的 map[string]interface{}

jsonObj.Set(10, "outter", "inner", "value")
jsonObj.SetP(20, "outter.inner.value2")
jsonObj.Set(30, "outter", "inner2", "value3")

fmt.Println(jsonObj.String())

// 输出
// {"outter":{"inner":{"value":10,"value2":20},"inner2":{"value3":30}}}
英文:

This looks promising.

//import "github.com/Jeffail/gabs"

jsonObj := gabs.New()
// or gabs.Consume(jsonObject) to work on an existing map[string]interface{}

jsonObj.Set(10, "outter", "inner", "value")
jsonObj.SetP(20, "outter.inner.value2")
jsonObj.Set(30, "outter", "inner2", "value3")

fmt.Println(jsonObj.String())

// Prints
// {"outter":{"inner":{"value":10,"value2":20},"inner2":{"value3":30}}}

huangapple
  • 本文由 发表于 2009年11月15日 18:19:30
  • 转载请务必保留本文链接:https://go.coder-hub.com/1737171.html
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