JSON-C结构介绍、使用
官方网站介绍http://www.json.org
JSON (JavaScript Object Notation) is a lightweight data-interchange format. It is easy for humans to read and write. It is easy for machines to parse and generate. It is based on a subset of the JavaScript Programming Language, Standard ECMA-262 3rd Edition - December 1999. JSON is a text format that is completely language independent but uses conventions that are familiar to programmers of the C-family of languages, including C, C++, C#, Java, JavaScript, Perl, Python, and many others. These properties make JSON an ideal data-interchange language.
JSON结构体如下:
typedefstruct cJSON {
structcJSON *next,*prev;
struct cJSON *child;
int type;
char * valuestring;
int valueint;
double valuedouble;
char *string;
}cJSON;
1、cJSON存储的时候是采用链表存储的,其访问方式像一颗树。每一个节点可以有兄妹节点和子节点,通过next/prev指针来查找上一节点或者下一节点;每个节点通过child指针来访问,进入下一层。
2、type一共有7种取值,分别是:
#define cJSON_False 0
#define cJSON_True 1
#define cJSON_NULL 2
#define cJSON_Number 3
#define cJSON_String 4
#define cJSON_Array 5
#define cJSON_Object 6
得到其职:
若是Number类型,则valueint或valuedouble中存储着值,若你期望的是int,则访问valueint,若期望的是double,则访问valuedouble,可以得到值。若是String类型的,则valuestring中存储着值,可以访问valuestring得到值。
若是多层嵌套的结构体要一层一层的进入,取值。实例:截取部分代码
JSON结构体
多层嵌套:
{
"glossary": {
"title": "example glossary",
"GlossDiv": {
"title": "S",
"GlossList": {
"GlossEntry": {
"ID": "SGML",
"SortAs": "SGML",
"GlossTerm": "Standard Generalized Markup Language",
"Acronym": "SGML",
"Abbrev": "ISO 8879:1986",
"GlossDef": {
"para": "A meta-markup language, used to create markup languages such as DocBook.",
"GlossSeeAlso": ["GML", "XML"]
},
"GlossSee": "markup"
}
}
}
}
}
cJSON *glossary = cJSON_GetObjectItem(json,"glossary");
char *title = cJSON_GetObjectItem(glossary,"title")->valuestring;
printf("title===%s\n",title);
上传文件内有JSON所有可能用到的函数
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