一、简介
cJSON 是一个以ANSI C (C89) 标准编写的轻量级JSON解析库。
二、How To Use
cJSON包含两个文件：cJSON.c、cJSON.h。在代码中includecJSON.h即可。例如：
目录结构：
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.
├── cJSON.c
├── cJSON.h
├── cJSON_test.c
├── Makefile
└── test.json
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cJSON_test.c:
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "cJSON.h"
#define JSON_FILE_PATH "./test.json"
#define JSON_FILE_SIZE 1024
int readValueFromFile(char* fileName, char* buff, int len)
{
int ret = -1;
FILE *fp = fopen(fileName, "r");
if (fp == NULL) {
printf("Unable to open file %s", fileName);
return -1;
} else {
if (fread(buff, sizeof(char), len, fp)>0) {
ret = 0;
}
}
fclose(fp);
return ret;
}
/**
* [printJson 遍历JSON]
*/
void printJson(cJSON * root)
{
char buf[500];
memset(buf, 0, sizeof(buf));
//遍历最外层json键值对
for(int i=0; i<cJSON_GetArraySize(root); i++) {
cJSON * item = cJSON_GetArrayItem(root, i);
//如果对应键的值仍为cJSON_Object就递归调用printJson
if(cJSON_Object == item->type) {
printJson(item);
}
//值不为json对象就直接打印出键和值
else {
printf("%s:%s\n", item->string, cJSON_Print(item));
}
}
}
int main()
{
cJSON *root = NULL;
cJSON *item = NULL;//cjson对象
char jsonStr[JSON_FILE_SIZE];
memset(jsonStr, 0, sizeof(jsonStr));
readValueFromFile(JSON_FILE_PATH, jsonStr, sizeof(jsonStr));
// printf("jsonStr=%s\n", jsonStr);
root = cJSON_Parse(jsonStr);
if (!root)
{
printf("Error before: [%s]\n",cJSON_GetErrorPtr());
}
else
{
printf("\n%s\n", "print all:");
printJson(root);
}
return 0;
}
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JSON:
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{
"station_name": "Module",
"structure": {
"module": {
"num": 1,
"rule": "023M",
"sn_len": 24
},
"cell": {
"num": 7,
"rule": "NULL",
"sn_len": 14
}
}
}
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输出结果：
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print all:
station_name:"Module"
num:1
rule:"023M"
sn_len:24
num:7
rule:"NULL"
sn_len:14
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