cjson编译与测试
1、下载源码
https://github.com/DaveGamble/cJSON
我下载的是1.7.0版本
2、解压到某个目录
3、编译
因为cjson只有4个文件，所以没有给出复杂的config文件，不需要进行配置，但是如果需要对代码进行详细的测试功能需要使用cmake来完成，这里我只做编译库的工作，所以cmake部分不做，这部分在readme中有详细的讲解。
make all
4、安装
make PREFIX=/home/renzhong/cJSON-master install
PREFIX这个参数是设置安装路径，这里它只会安装动态库，静态库在源码包的目录下能找到。
经过这一步之后就会在安装路径下找到include和lib。
5、测试程序
我这里提供两个测试程序，一个是官方给的test.c，主要是创建json文件，一个是网上找的读取json文件
/*
Copyright (c) 2009-2017 Dave Gamble and cJSON contributors
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/
#include
#include
#include
#include
#include "cJSON.h"
/* Used by some code below as an example datatype. */
struct record
{
const char *precision;
double lat;
double lon;
const char *address;
const char *city;
const char *state;
const char *zip;
const char *country;
};
/* Create a bunch of objects as demonstration. */
static int print_preallocated(cJSON *root)
{
/* declarations */
char *out = NULL;
char *buf = NULL;
char *buf_fail = NULL;
size_t len = 0;
size_t len_fail = 0;
/* formatted print */
out = cJSON_Print(root);
/* create buffer to succeed */
/* the extra 5 bytes are because of inaccuracies when reserving memory */
len = strlen(out) + 5;
buf = (char*)malloc(len);
if (buf == NULL)
{
printf("Failed to allocate memory.\n");
exit(1);
}
/* create buffer to fail */
len_fail = strlen(out);
buf_fail = (char*)malloc(len_fail);
if (buf_fail == NULL)
{
printf("Failed to allocate memory.\n");
exit(1);
}
/* Print to buffer */
if (!cJSON_PrintPreallocated(root, buf, (int)len, 1)) {
printf("cJSON_PrintPreallocated failed!\n");
if (strcmp(out, buf) != 0) {
printf("cJSON_PrintPreallocated not the same as cJSON_Print!\n");
printf("cJSON_Print result:\n%s\n", out);
printf("cJSON_PrintPreallocated result:\n%s\n", buf);
}
free(out);
free(buf_fail);
free(buf);
return -1;
}
/* success */
printf("%s\n", buf);
/* force it to fail */
if (cJSON_PrintPreallocated(root, buf_fail, (int)len_fail, 1)) {
printf("cJSON_PrintPreallocated failed to show error with insufficient memory!\n");
printf("cJSON_Print result:\n%s\n", out);
printf("cJSON_PrintPreallocated result:\n%s\n", buf_fail);
free(out);
free(buf_fail);
free(buf);
return -1;
}
free(out);
free(buf_fail);
free(buf);
return 0;
}
/* Create a bunch of objects as demonstration. */
static void create_objects(void)
{
/* declare a few. */
cJSON *root = NULL;
cJSON *fmt = NULL;
cJSON *img = NULL;
cJSON *thm = NULL;
cJSON *fld = NULL;
int i = 0;
/* Our "days of the week" array: */
const char *strings[7] =
{
"Sunday",
"Monday",
"Tuesday",
"Wednesday",
"Thursday",
"Friday",
"Saturday"
};
/* Our matrix: */
int numbers[3][3] =
{
{0, -1, 0},
{1, 0, 0},
{0 ,0, 1}
};
/* Our "gallery" item: */
int ids[4] = { 116, 943, 234, 38793 };
/* 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"
}
};
volatile double zero = 0.0;
/* 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, "null", cJSON_CreateNull());
cJSON_AddItemToObject(root, "true", cJSON_CreateTrue());
cJSON_AddItemToObject(root, "false", cJSON_CreateFalse());
cJSON_AddItemToObject(root, "bool", cJSON_CreateBool(false));
cJSON_AddItemToObject(root, "num", cJSON_CreateNumber(3.1415926));
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);
/* Print to text */
if (print_preallocated(root) != 0) {
cJSON_Delete(root);
exit(EXIT_FAILURE);
}
cJSON_ReplaceItemInObject(root, "name", cJSON_CreateString("andy"));
/* Print to text */
if (print_preallocated(root) != 0) {
cJSON_Delete(root);
exit(EXIT_FAILURE);
}
cJSON_Delete(root);
/* Our "days of the week" array: */
root = cJSON_CreateStringArray(strings, 7);
if (print_preallocated(root) != 0) {
cJSON_Delete(root);
exit(EXIT_FAILURE);
}
cJSON_Delete(root);
/* Our matrix: */
root = cJSON_CreateArray();
for (i = 0; i < 3; i++)
{
cJSON_AddItemToArray(root, cJSON_CreateIntArray(numbers[i], 3));
}
/* cJSON_ReplaceItemInArray(root, 1, cJSON_CreateString("Replacement")); */
if (print_preallocated(root) != 0) {
cJSON_Delete(root);
exit(EXIT_FAILURE);
}
cJSON_Delete(root);
/* Our "gallery" item: */
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));
if (print_preallocated(root) != 0) {
cJSON_Delete(root);
exit(EXIT_FAILURE);
}
cJSON_Delete(root);
/* Our array of "records": */
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)); */
if (print_preallocated(root) != 0) {
cJSON_Delete(root);
exit(EXIT_FAILURE);
}
cJSON_Delete(root);
root = cJSON_CreateObject();
cJSON_AddNumberToObject(root, "number", 1.0 / zero);
if (print_preallocated(root) != 0) {
cJSON_Delete(root);
exit(EXIT_FAILURE);
}
cJSON_Delete(root);
}
int main(void)
{
/* print the version */
printf("Version: %s\n", cJSON_Version());
/* Now some samplecode for building objects concisely: */
create_objects();
return 0;
} /***********************************************************************************
{
"message": "json test",
"allRowCount": 2,
"root": [{
"value": "2015-11-16 11:15",
"id": "2015_20110.10000",
"sex": "famale"
}],
"success": "true"
}
************************************************************************************/
#include
#include
#include
#include "cJSON.h"
static int print_jsom(char *json_string)
{
char *out;
/* declarations */
char *buf = NULL;
size_t len = 0;
cJSON *jsonroot = cJSON_Parse(json_string);
out=cJSON_Print(jsonroot);
printf("%s\n",out);
/* create buffer to succeed */
/* the extra 5 bytes are because of inaccuracies when reserving memory */
len = strlen(out) + 5;
buf = (char*)malloc(len);
if (buf == NULL)
{
printf("Failed to allocate memory.\n");
exit(1);
}
/* Print to buffer */
if (!cJSON_PrintPreallocated(jsonroot, buf, (int)len, 1)) {
printf("cJSON_PrintPreallocated failed!\n");
if (strcmp(out, buf) != 0) {
printf("cJSON_PrintPreallocated not the same as cJSON_Print!\n");
printf("cJSON_Print result:\n%s\n", out);
printf("cJSON_PrintPreallocated result:\n%s\n", buf);
}
free(out);
free(buf);
return -1;
}
/* success */
printf("%s\n", buf);
cJSON_Delete(jsonroot);
free(out);
return 1;
}
static int print_file(char *filename)
{
FILE *fp;
int flen;
char *p;
if ((fp = fopen (filename, "r")) == NULL)
{
printf("file open error\n");
exit(0);
}
fseek(fp, 0, SEEK_END);
flen = ftell(fp);
p = (char *)malloc(flen + 1);
fseek (fp, 0, SEEK_SET);
fread (p , flen, 1, fp);
print_jsom(p);
fclose(fp);
free(p);
return 1;
}
int main (int argc, const char * argv[])
{
char *filename="fromnet.json";
//print_file(filename);
//return 0;
char *my_json_string = "{ \
\n\"message\":\"json test\", \
\n\"allRowCount\":2, \
\n\"root\":[{ \
\n \"value\":\"2015-11-16 11:15\", \
\n \"id\":\"2015_20110.10000\", \
\n \"sex\":\"famale\" \
\n }], \
\n\"success\":false \
\n}";
print_jsom(my_json_string);
cJSON *jsonroot = cJSON_Parse(my_json_string);
printf("success=%s\n",cJSON_GetObjectItem(jsonroot, "success")->valuestring);
printf("success=%d\n",cJSON_IsTrue(cJSON_GetObjectItem(jsonroot, "success")));
int taskNum = cJSON_GetObjectItem(jsonroot,"allRowCount")->valueint;
printf("allRowCount=%d\n", taskNum);
cJSON *taskArry=cJSON_GetObjectItem(jsonroot,"root");//取数组
int arrySize=cJSON_GetArraySize(taskArry);//数组大小
printf("array size:%d\n",arrySize);
cJSON *tasklist=taskArry->child;//子对象
char *value = NULL;
printf("------------------------\n");
while(tasklist!=NULL) {
value = cJSON_GetObjectItem(tasklist,"value")->valuestring;
if (value && strcmp(value, "")) {
printf("value=%s\n", value);
}
value = cJSON_GetObjectItem(tasklist,"id")->valuestring;
if (value && strcmp(value, "")) {
printf("id=%s\n", value);
}
value = cJSON_GetObjectItem(tasklist,"sex")->valuestring;
if (value && strcmp(value, "")) {
printf("sex=%s\n", value);
}
tasklist=tasklist->next;
}
cJSON_Delete(jsonroot);
return 1;
}
编译时没有遇到什么问题。
下面来讲一下对于cjson的交叉编译，也很简单。
6、交叉编译
make all CC=arm-linux-gcc
CC指的是使用的交叉编译链，每个人的命名可能不同，需要根据情况修改。
7、安装
make PREFIX=/home/linux/arm/cJson install
8、动态库拷贝到arm环境下
cp -a libcjson*.so* /nfsroot/rootfs/lib/