你看到的这个文章来自于http://www.cnblogs.com/ayanmw
cJSON官网是：http://sourceforge.net/projects/cjson/?source=recommended
最新版本是2013年的，与2009年的变化不是很大。
看了代码，觉得挺好，只是是C语言的，不够好。
就改良了一下，内存自己管理。使用std::string
http://files.cnblogs.com/ayanmw/cJSON_cpp_myversion.zip
使用起来如下：
#include <stdio.h>
#include <stdlib.h>
#include "cJSON.h"#define PS(V) printf(#V"=%s\n",V);
#define PI(V) printf(#V"=%d\n",V);
#define PF(V) printf(#V"=%f\n",V);int main (int argc, const char * argv[]) {
AddStack(__FUNCTION__);const char * myjson="{\"name\":\"value\",\"jsonobject\":{\"int\":5,\"true\":true,\"false\":false,\"null\":null},\"jsonarray\":[\"array1\",\"array2\",12,true,false,null,\"12\",-1.2]}";
cJSON * jsonroot =new cJSON();
if(0==jsonroot->cJSON_Parse(myjson))
printf("Error to cJSON_Parse :%s %x\n",jsonroot->cJSON_GetErrorPtr(),jsonroot->cJSON_GetErrorPtr());
else{
const char * out=jsonroot->cJSON_Print( ).c_str();
printf("myjson=%s\n",out);
PS(jsonroot->toString().c_str());
const char * value=jsonroot->cJSON_GetString( "name").c_str();
PS(value);cJSON *jsonobject=jsonroot->cJSON_GetObjectItem( "jsonobject");
PS(jsonroot->cJSON_GetString("jsonobject").c_str());
PS(jsonobject->toString().c_str());PS(jsonobject->cJSON_GetString("null").c_str());
PS(jsonobject->cJSON_GetString("int").c_str());
PS(jsonobject->cJSON_GetString("true").c_str());PI(jsonobject->cJSON_GetInt("int") );
PI(jsonobject->cJSON_GetBoolean("true"));
PI( jsonobject->cJSON_GetBoolean("false") );cJSON *jsonarray=jsonroot->cJSON_GetObjectItem("jsonarray");
PS(jsonroot->cJSON_GetString("jsonarray").c_str());
PS(jsonarray->toString().c_str());PI( jsonroot->cJSON_GetArraySize( ) );
PI( jsonobject->cJSON_GetArraySize( ) );
PI(jsonarray->cJSON_GetArraySize( ));cJSON *arrayitem=jsonarray->cJSON_GetArrayItem( 0);
PS(arrayitem->valuestring);
}
PS("END Mark");
delete jsonroot;
return 0;
}
toString()可以轻松获取到json的内容信息。以上是解析的。
生成json可以看cJSON的test.c 文件。
#include <stdio.h>
#include <stdlib.h>
#include "cJSON.h"/* Parse text to JSON, then render back to text, and print! */
void doit(char *text)
{
char *out;cJSON *json;json=cJSON_Parse(text);
if (!json) {printf("Error before: [%s]\n",cJSON_GetErrorPtr());}
else
{
out=cJSON_Print(json);
cJSON_Delete(json);
printf("%s\n",out);
free(out);
}
}/* Read a file, parse, render back, etc. */
void dofile(char *filename)
{
FILE *f=fopen(filename,"rb");fseek(f,0,SEEK_END);long len=ftell(f);fseek(f,0,SEEK_SET);
char *data=(char*)malloc(len+1);fread(data,1,len,f);fclose(f);
doit(data);
free(data);
}/* Used by some code below as an example datatype. */
struct record {const char *precision;double lat,lon;const char *address,*city,*state,*zip,*country; };/* Create a bunch of objects as demonstration. */
void create_objects()
{
cJSON *root,*fmt,*img,*thm,*fld;char *out;int i; /* declare a few. *//* Here we construct some JSON standards, from the JSON site. */
/* Our "Video" datatype: */
root=cJSON_CreateObject();
cJSON_AddItemToObject(root, "name", cJSON_CreateString("Jack (\"Bee\") Nimble"));
cJSON_AddItemToObject(root, "format", fmt=cJSON_CreateObject());
cJSON_AddStringToObject(fmt,"type", "rect");
cJSON_AddNumberToObject(fmt,"width", 1920);
cJSON_AddNumberToObject(fmt,"height", 1080);
cJSON_AddFalseToObject (fmt,"interlace");
cJSON_AddNumberToObject(fmt,"frame rate", 24);out=cJSON_Print(root); cJSON_Delete(root); printf("%s\n",out); free(out); /* Print to text, Delete the cJSON, print it, release the string. */
/* Our "days of the week" array: */
const char *strings[7]={"Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"};
root=cJSON_CreateStringArray(strings,7);out=cJSON_Print(root); cJSON_Delete(root); printf("%s\n",out); free(out);
/* Our matrix: */
int numbers[3][3]={{0,-1,0},{1,0,0},{0,0,1}};
root=cJSON_CreateArray();
for (i=0;i<3;i++) cJSON_AddItemToArray(root,cJSON_CreateIntArray(numbers[i],3));/* cJSON_ReplaceItemInArray(root,1,cJSON_CreateString("Replacement")); */
out=cJSON_Print(root); cJSON_Delete(root); printf("%s\n",out); free(out);
/* Our "gallery" item: */
int ids[4]={116,943,234,38793};
root=cJSON_CreateObject();
cJSON_AddItemToObject(root, "Image", img=cJSON_CreateObject());
cJSON_AddNumberToObject(img,"Width",800);
cJSON_AddNumberToObject(img,"Height",600);
cJSON_AddStringToObject(img,"Title","View from 15th Floor");
cJSON_AddItemToObject(img, "Thumbnail", thm=cJSON_CreateObject());
cJSON_AddStringToObject(thm, "Url", "http:/*www.example.com/image/481989943");
cJSON_AddNumberToObject(thm,"Height",125);
cJSON_AddStringToObject(thm,"Width","100");
cJSON_AddItemToObject(img,"IDs", cJSON_CreateIntArray(ids,4));out=cJSON_Print(root); cJSON_Delete(root); printf("%s\n",out); free(out);
/* Our array of "records": */
struct record fields[2]={
{"zip",37.7668,-1.223959e+2,"","SAN FRANCISCO","CA","94107","US"},
{"zip",37.371991,-1.22026e+2,"","SUNNYVALE","CA","94085","US"}};root=cJSON_CreateArray();
for (i=0;i<2;i++)
{
cJSON_AddItemToArray(root,fld=cJSON_CreateObject());
cJSON_AddStringToObject(fld, "precision", fields[i].precision);
cJSON_AddNumberToObject(fld, "Latitude", fields[i].lat);
cJSON_AddNumberToObject(fld, "Longitude", fields[i].lon);
cJSON_AddStringToObject(fld, "Address", fields[i].address);
cJSON_AddStringToObject(fld, "City", fields[i].city);
cJSON_AddStringToObject(fld, "State", fields[i].state);
cJSON_AddStringToObject(fld, "Zip", fields[i].zip);
cJSON_AddStringToObject(fld, "Country", fields[i].country);
}/* cJSON_ReplaceItemInObject(cJSON_GetArrayItem(root,1),"City",cJSON_CreateIntArray(ids,4)); */
out=cJSON_Print(root); cJSON_Delete(root); printf("%s\n",out); free(out);
}
int main (int argc, const char * argv[]) {
/* a bunch of json: */
char text1[]="{\n\"name\": \"Jack (\\\"Bee\\\") Nimble\", \n\"format\": {\"type\": \"rect\", \n\"width\": 1920, \n\"height\": 1080, \n\"interlace\": false,\"frame rate\": 24\n}\n}";
char text2[]="[\"Sunday\", \"Monday\", \"Tuesday\", \"Wednesday\", \"Thursday\", \"Friday\", \"Saturday\"]";
char text3[]="[\n [0, -1, 0],\n [1, 0, 0],\n [0, 0, 1]\n ]\n";
char text4[]="{\n \"Image\": {\n \"Width\": 800,\n \"Height\": 600,\n \"Title\": \"View from 15th Floor\",\n \"Thumbnail\": {\n \"Url\": \"http:/*www.example.com/image/481989943\",\n \"Height\": 125,\n \"Width\": \"100\"\n },\n \"IDs\": [116, 943, 234, 38793]\n }\n }";
char text5[]="[\n {\n \"precision\": \"zip\",\n \"Latitude\": 37.7668,\n \"Longitude\": -122.3959,\n \"Address\": \"\",\n \"City\": \"SAN FRANCISCO\",\n \"State\": \"CA\",\n \"Zip\": \"94107\",\n \"Country\": \"US\"\n },\n {\n \"precision\": \"zip\",\n \"Latitude\": 37.371991,\n \"Longitude\": -122.026020,\n \"Address\": \"\",\n \"City\": \"SUNNYVALE\",\n \"State\": \"CA\",\n \"Zip\": \"94085\",\n \"Country\": \"US\"\n }\n ]";/* Process each json textblock by parsing, then rebuilding: */
doit(text1);
doit(text2);
doit(text3);
doit(text4);
doit(text5);/* Parse standard testfiles: */
/* dofile("../../tests/test1"); */
/* dofile("../../tests/test2"); */
/* dofile("../../tests/test3"); */
/* dofile("../../tests/test4"); */
/* dofile("../../tests/test5"); *//* Now some samplecode for building objects concisely: */
create_objects();return 0;
}
感觉比jsoncpp 代码简洁。算法看起来都是简单精炼的。很好的。
转载请注明出处：http://www.cnblogs.com/ayanmw 我会很高兴的！
c++ 使用json的库。cJSON,布布扣,bubuko.com