JSON部分API说明：

示例程序：

#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <string.h>

#include "json.h"

int main(int argc, char **argv)
{
  struct json_tokener *tok;
  struct json_object *my_string, *my_int, *my_object, *my_array;
  struct json_object *new_obj;
  int i;

  my_string = json_object_new_string("\t");
/*输出 my_string=   */
  printf("my_string=%s\n", json_object_get_string(my_string));  // \t
/*转换json格式字符串 输出my_string.to_string()="\t"*/
printf("my_string.to_string()=%s\n", json_object_to_json_string(my_string));  //"\t"
/*释放资源*/
  json_object_put(my_string);

  my_string = json_object_new_string("\\");
  printf("my_string=%s\n", json_object_get_string(my_string)); // \
  printf("my_string.to_string()=%s\n", json_object_to_json_string(my_string)); // \\
  json_object_put(my_string);

  my_string = json_object_new_string("foo");
  printf("my_string=%s\n", json_object_get_string(my_string));
  printf("my_string.to_string()=%s\n", json_object_to_json_string(my_string)); //foo

  my_int = json_object_new_int(9);
  printf("my_int=%d\n", json_object_get_int(my_int));
  printf("my_int.to_string()=%s\n", json_object_to_json_string(my_int)); // 9

  /*创建个空json对象值数组类型*/
  my_array = json_object_new_array();
  /*添加json值类型到数组中*/
  json_object_array_add(my_array, json_object_new_int(1));
  json_object_array_add(my_array, json_object_new_int(2));
  json_object_array_add(my_array, json_object_new_int(3));
  json_object_array_put_idx(my_array, 4, json_object_new_int(5));
  printf("my_array=\n");
  for(i=0; i < json_object_array_length(my_array); i++) {
    struct json_object *obj = json_object_array_get_idx(my_array, i);
    printf("\t[%d]=%s\n", i, json_object_to_json_string(obj));
  }
  printf("my_array.to_string()=%s\n", json_object_to_json_string(my_array));    // 1 2 3 null 5

  my_object = json_object_new_object();
  /*添加json名称和值到json对象集合中*/
  json_object_object_add(my_object, "abc", json_object_new_int(12));
  json_object_object_add(my_object, "foo", json_object_new_string("bar"));
  json_object_object_add(my_object, "bool0", json_object_new_boolean(0));
  json_object_object_add(my_object, "bool1", json_object_new_boolean(1));
  json_object_object_add(my_object, "baz", json_object_new_string("bang"));
  /*同样的key 添加会替换掉*/
  json_object_object_add(my_object, "baz", json_object_new_string("fark"));
  json_object_object_del(my_object, "baz");
   
  printf("my_object=\n");
  /*遍历json对象集合*/
  json_object_object_foreach(my_object, key, val) {
    printf("\t%s: %s\n", key, json_object_to_json_string(val));
  }
  printf("my_object.to_string()=%s\n", json_object_to_json_string(my_object));

 /*对些不规则的串做了些解析测试*/
  new_obj = json_tokener_parse("\"\003\"");
  printf("new_obj.to_string()=%s\n", json_object_to_json_string(new_obj));
  json_object_put(new_obj);

  new_obj = json_tokener_parse("/* hello */\"foo\"");
  printf("new_obj.to_string()=%s\n", json_object_to_json_string(new_obj));
  json_object_put(new_obj);

  new_obj = json_tokener_parse("// hello\n\"foo\"");
  printf("new_obj.to_string()=%s\n", json_object_to_json_string(new_obj));
  json_object_put(new_obj);

  new_obj = json_tokener_parse("\"\\u0041\\u0042\\u0043\"");
  printf("new_obj.to_string()=%s\n", json_object_to_json_string(new_obj));
  json_object_put(new_obj);

  new_obj = json_tokener_parse("null");
  printf("new_obj.to_string()=%s\n", json_object_to_json_string(new_obj));
  json_object_put(new_obj);

  new_obj = json_tokener_parse("True");
  printf("new_obj.to_string()=%s\n", json_object_to_json_string(new_obj));
  json_object_put(new_obj);

  new_obj = json_tokener_parse("12");
  printf("new_obj.to_string()=%s\n", json_object_to_json_string(new_obj));
  json_object_put(new_obj);

  
  new_obj = json_tokener_parse("12.3");
  /*得到json double类型
  printf("new_obj.to_string()=%s\n", json_object_to_json_string(new_obj));
  json_object_put(new_obj);

  new_obj = json_tokener_parse("[\"\\n\"]");
  printf("new_obj.to_string()=%s\n", json_object_to_json_string(new_obj));
  json_object_put(new_obj);

  new_obj = json_tokener_parse("[\"\\nabc\\n\"]");
  printf("new_obj.to_string()=%s\n", json_object_to_json_string(new_obj));
  json_object_put(new_obj);

  new_obj = json_tokener_parse("[null]");
  printf("new_obj.to_string()=%s\n", json_object_to_json_string(new_obj));
  json_object_put(new_obj);

  new_obj = json_tokener_parse("[]");
  printf("new_obj.to_string()=%s\n", json_object_to_json_string(new_obj));
  json_object_put(new_obj);

  new_obj = json_tokener_parse("[false]");
  printf("new_obj.to_string()=%s\n", json_object_to_json_string(new_obj));
  json_object_put(new_obj);

  new_obj = json_tokener_parse("[\"abc\",null,\"def\",12]");
  printf("new_obj.to_string()=%s\n", json_object_to_json_string(new_obj));
  json_object_put(new_obj);

  new_obj = json_tokener_parse("{}");
  printf("new_obj.to_string()=%s\n", json_object_to_json_string(new_obj));
  json_object_put(new_obj);

  new_obj = json_tokener_parse("{ \"foo\": \"bar\" }");
  printf("new_obj.to_string()=%s\n", json_object_to_json_string(new_obj));
  json_object_put(new_obj);

  new_obj = json_tokener_parse("{ \"foo\": \"bar\", \"baz\": null, \"bool0\": true }");
  printf("new_obj.to_string()=%s\n", json_object_to_json_string(new_obj));
  json_object_put(new_obj);

  new_obj = json_tokener_parse("{ \"foo\": [null, \"foo\"] }");
  printf("new_obj.to_string()=%s\n", json_object_to_json_string(new_obj));
  json_object_put(new_obj);

  new_obj = json_tokener_parse("{ \"abc\": 12, \"foo\": \"bar\", \"bool0\": false, \"bool1\": true, \"arr\": [ 1, 2, 3, null, 5 ] }");
  printf("new_obj.to_string()=%s\n", json_object_to_json_string(new_obj));
  json_object_put(new_obj);

  new_obj = json_tokener_parse("{ foo }");
  if(is_error(new_obj)) printf("got error as expected\n");

  new_obj = json_tokener_parse("foo");
  if(is_error(new_obj)) printf("got error as expected\n");

  new_obj = json_tokener_parse("{ \"foo");
  if(is_error(new_obj)) printf("got error as expected\n");

  /* test incremental parsing */
  tok = json_tokener_new();
  new_obj = json_tokener_parse_ex(tok, "{ \"foo", 6);
  if(is_error(new_obj)) printf("got error as expected\n");
  new_obj = json_tokener_parse_ex(tok, "\": {\"bar", 8);
  if(is_error(new_obj)) printf("got error as expected\n");
  new_obj = json_tokener_parse_ex(tok, "\":13}}", 6);
  printf("new_obj.to_string()=%s\n", json_object_to_json_string(new_obj));
  json_object_put(new_obj);  
  json_tokener_free(tok);

  json_object_put(my_string);
  json_object_put(my_int);
  json_object_put(my_object);
  json_object_put(my_array); 
/*如果前面没有添加到对象中， 必须显示释放，
 如果添加到对象中，已经释放对象，则无需调用， 在这务必小心，否则很容易内存泄漏*/

  return 0;
}