利用rapidjson解析嵌套的json
看json串1:{"system":{"version":"v2.6.1", "name":"value"}}
废话少说, 直接撸代码:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
|
#include <iostream> #include <stdio.h> #include<unistd.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include<sstream> // 请自己下载开源的rapidjson #include "rapidjson/prettywriter.h" #include "rapidjson/rapidjson.h" #include "rapidjson/document.h" #include "rapidjson/stringbuffer.h" #include "rapidjson/writer.h" #include "rapidjson/memorystream.h" using namespace std; using rapidjson::Document; using rapidjson::StringBuffer; using rapidjson::Writer; using namespace rapidjson; string getVersion( const string &jvStr) { Document document; if (document.Parse(jvStr.c_str()).HasParseError() || !document.HasMember( "system" )) { return "" ; } const rapidjson::Value &jvObject = document[ "system" ]; if (!jvObject.IsObject()) { return "" ; } if (!jvObject.HasMember( "version" )) { return "" ; } const rapidjson::Value &jv = jvObject[ "version" ]; return jv.GetString(); } int main( int argc, char *argv[]) { string s = "{\"system\":{\"version\":\"v2.6.1\", \"name\":\"value\"}}" ; cout << s << endl; cout << getVersion(s) << endl; return 0; } |
结果:
{"system":{"version":"v2.6.1", "name":"value"}}
v2.6.1
再看字符串:{"system": "{\"version\":\"v2.6.1\", \"name\":\"value\"}"}
直接上马:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
|
#include <iostream> #include <stdio.h> #include<unistd.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include<sstream> // 请自己下载开源的rapidjson #include "rapidjson/prettywriter.h" #include "rapidjson/rapidjson.h" #include "rapidjson/document.h" #include "rapidjson/stringbuffer.h" #include "rapidjson/writer.h" #include "rapidjson/memorystream.h" using namespace std; using rapidjson::Document; using rapidjson::StringBuffer; using rapidjson::Writer; using namespace rapidjson; string getStringFromJson( const string &jsStr, const string &strKey) { Document document; if (document.Parse(jsStr.c_str()).HasParseError() || !document.HasMember(strKey.c_str())) { return "" ; } const rapidjson::Value &jv = document[strKey.c_str()]; return jv.GetString(); } int main( int argc, char *argv[]) { string s = "{\"system\": \"{\\\"version\\\":\\\"v2.6.1\\\", \\\"name\\\":\\\"value\\\"}\"}" ; cout << s << endl; string str = getStringFromJson(s, "system" ); cout << str << endl; cout << getStringFromJson(str, "version" ) << endl; return 0; } |
结果:
{"system": "{\"version\":\"v2.6.1\", \"name\":\"value\"}"}
{"version":"v2.6.1", "name":"value"}
v2.6.1
第二种方式的json串,看起来太恶心了。
另外,再次强调一下,json串解析的时候,容易core dump,所以要做好异常判断,也要注意类型。
总结
以上就是这篇文章的全部内容了,希望本文的内容对大家的学习或者工作具有一定的参考学习价值,谢谢大家对服务器之家的支持。如果你想了解更多相关内容请查看下面相关链接