delphi怎么得到下面的json数据中的多个节点值。

披着虎皮的石头 2013-06-21 10:36:46

下面是UlkJson的第三方控件，来读取json的值。
如何取得childobject2":[{"obj2str1":"2one"},{"obj2str1":"2two"}]}中的
2one、2two的值？

// Sample 2: how to get child type and subobject fields

//

// Leonid Koninin, 02/03/2007

program sample2;

{$APPTYPE CONSOLE}

uses SysUtils, uLkJSON in 'uLkJSON.pas';

var JSon, XJSon :TlkJSONobject; JSonNode :TlkJSONString; JSonNodeList :TlkJSONlist; Str :String; i :Integer;

begin

  Str := '{"string1":"one", "string2":"two", '

         +'"childobject" : {"objstr1" :"Oone",  "objstr2" :"Otwo"},'

         +'"childobject2":[{"obj2str1":"2one"},{"obj2str1":"2two"}]}'; writeln(Str);



  JSon := TlkJSON.ParseText(Str) as TlkJSONobject; // restore object (parse text)



  if not assigned(JSon) then begin // how to obtain type of child

      writeln('error: xs not assigned!'); readln; //exit;

  end else begin //Field[] is 方式判断类型

      if JSon.Field['childobject'] is TlkJSONString  then writeln('type: xs is string!'); //string

      if JSon.Field['childobject'] is TlkJSONlist    then writeln('type: xs is list!');   //list  多个Json子节点

      if JSon.Field['childobject'] is TlkJSONobject  then writeln('type: xs is object!'); //Oject 单个json子节点



      //以下类型，实际不常用

      if JSon.Field['childobject'] is TlkJSONnumber  then writeln('type: xs is number!');  //数字 value前后不加引号

      if JSon.Field['childobject'] is TlkJSONboolean then writeln('type: xs is boolean!'); //boolean

      if JSon.Field['childobject'] is TlkJSONnull    then writeln('type: xs is null!');    //Null    改为空格值

    end;



  //Filed[].SelfType 方式判断类型

  case JSon.Field['childobject'].SelfType of //the other way (0.93+)

    jsString  :writeln('other type: xs is string');

    jsObject  :writeln('other type: xs is object');

    jsList    :writeln('other type: xs is list');

    

    jsNumber  :writeln('other type: xs is number');

    jsBoolean :writeln('other type: xs is boolean');

    jsNull    :writeln('other type: xs is null');

    jsBase    :writeln('other type: xs is base');

  end;

  writeln('self-type name: ', JSon.Field['childobject'].SelfTypeName);



  XJSon :=JSon.Field['childobject'] as TlkJSONobject; //JSON中，有下级节点的，不像xml那样称为节点对象，仍称为JSOn对象



  //Field[] as方式取值,完美

  JSonNode :=XJSon.Field['objstr1'] as TlkJSONString; //we know what xs chilren are strings

  writeln(JSonNode.value);



  JSonNode :=XJSon.Field['objstr2'] as TlkJSONstring;

  writeln(JSonNode.value);



  //getstring，快速

  writeln(XJSon.getString('objstr1')); //new v0.99 +syntax!

  writeln(XJSon.getString('objstr2')); readln;



  JSon.Free;

end.