xml文档与字符串的转换实例

迈不过友情╰ 2022-03-12 03:08 592阅读 0赞

`在linux下经常要进行socket通信，而数据流多采用目前流行的xml格式，这就会有两个用的比较多的功能：`

`1、接收端将收到的字符串转换成xml格式的数据；`

`2、发送端将xml格式的数据转换成字符串发送。`

`运用libxml2组件进行上述操作实际上是xmlDocPtr和xmlChar两种类型之间的转换。`

`1. xmlDocPtr -> xmlChar`

`xmlDocPtr doc;`

`xmlChar *xmlbuff;`

`int buffersize;`

`xmlDocDumpFormatMemory(doc, &xmlbuff, &buffersize, 1);`

`2. xmlChar -> xmlDocPtr`

`xmlDocPtr doc;`

`char * cData;`

`doc = xmlParseMemory(docname, strlen(cData)+1);`

`怎样把xmlChar转换成char就无须多讲了，直接用（char*）强行转换也行。`

`注意：要保证 xmlChar到xmlDocPtr转换的成功需要注意一个细节，那就是字符串必须是有用的数具体，类似于<?xml version="1.0" encoding="UTF-8"?>这样的头要去掉`

`下面的例子，srv端等待6601端口的数据，并使用XML解析，取得其中的name和age项，并打印到终端`

`client端读取一个XML文件，并把读取的数据转换为字符串，向服务端的端口发送`

/*srv.c By ksir in 2011-10-14*/
    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    #include <ctype.h>
    #include <sys/socket.h>
    #include <netinet/in.h>
    #include <arpa/inet.h>
    #include <libxml/parser.h>
    #include <libxml/xmlmemory.h>
    
    #define MAXLINE 80
    int port = 6601;		/*Port of socket*/
    
    /*parse XML and show content of 'name','age'*/
    int parseXML(xmlDocPtr tmpdoc)
    {
    	//printf("This is in parseXML\n");
        xmlNodePtr curNode; /*Keep node of the xml tree*/
        xmlChar *szKey;
    
        /*Get the root Node from tmpdoc*/
        curNode = xmlDocGetRootElement(tmpdoc);
        /*check the content of the document*/
        if (NULL == curNode)
        {
            xmlFreeDoc(tmpdoc);
            return -3;
        }
    
        /*Check the type of the root element*/
        if(xmlStrcmp(curNode->name,BAD_CAST"n"))
        {
            printf("Document of the wrong type");
            xmlFreeDoc(tmpdoc);
            return -4;
        }
        curNode = curNode->xmlChildrenNode;
        xmlNodePtr propNpdePtr =curNode;
        while (curNode != NULL)
        {
    		/*compare element nodes,show the content*/
            if( !(xmlStrcmp(curNode->name,(const xmlChar *)"name")))
            {
                szKey = xmlNodeGetContent(curNode);
                printf("name:%s\n",szKey);
                xmlFree(szKey);
            }
    		else if( !(xmlStrcmp(curNode->name,(const xmlChar *)"age")))
    		{
    			printf("Age:%s\n",xmlNodeGetContent(curNode));
    		}
    		/*traverse*/
            curNode = curNode->next;
        }
        xmlFreeDoc(tmpdoc);
        return 0;
    }
    
    int main(void)
    {
    	struct sockaddr_in sin;
    	struct sockaddr_in rin;
    	int sock_fd;
    	int address_size;
    	char buf[MAXLINE];
    	char str[INET_ADDRSTRLEN];
    	int len;
    	int n;
    
    	xmlDocPtr doc;
    
    	bzero(&sin, sizeof(sin));
    	sin.sin_family = AF_INET;
    	sin.sin_addr.s_addr = INADDR_ANY;
    	sin.sin_port = htons(port);
    
    
    	sock_fd = socket(AF_INET, SOCK_DGRAM, 0);
    	if (-1 == sock_fd)
    	{
    		perror("call to socket");
    		exit(1);
    	}
    	n = bind(sock_fd, (struct sockaddr *)&sin, sizeof(sin));
    	if (-1 == n)
    	{
    		perror("call to bind");
    		exit(1);
    	}
    
    	while(1)
    	{
    		address_size = sizeof(rin);
    		n = recvfrom(sock_fd,buf,MAXLINE,0,(struct sockaddr *)&rin,
    				&address_size);
    		if (-1 == n)
    		{
    			perror("call to recvfrom.\n");
    			exit(1);
    		}
    	//	printf("you ip is %s at port %d:%s\n",
    	//			inet_ntop(AF_INET, &rin.sin_addr,str,sizeof(str)),
    	//			ntohs(rin.sin_port),(char *)buf);
    
    		/*transfer buf to xml*/
    		doc = xmlParseMemory((char *)buf,strlen(buf)+1);
    		if (NULL == doc)
    		{
    			printf("xmlParseMemory fail\n");
    			return -2;
    		}
    		parseXML(doc);
     	}
    	return 0;
    }

客户端代码：

/*Client.c by ksir in 2011-10-14*/
    
    #include<stdio.h>
    #include<string.h>
    #include<stdlib.h>
    #include<sys/types.h>
    #include<unistd.h>
    #include<sys/socket.h>
    #include<linux/in.h>
    #include <libxml/parser.h>
    #include <libxml/xmlmemory.h>
    
    
    int main(int argc,char *argv[])
    {
    	if(argc<2){
    		printf("Please input a file !\n");
    		exit(0);
    	}
    	int sock;
    	struct sockaddr_in toAddr;
    	struct sockaddr_in fromAddr;
    	
    	unsigned int fromLen;
    	char recvBuffer[128];
    	sock=socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP);
    	if(sock<0){
    		printf("Sock failed!\n");
    		exit(1);
    	}	
    	
    	memset(&toAddr,0,sizeof(toAddr));
    	
    	toAddr.sin_family=AF_INET;
    	toAddr.sin_addr.s_addr=inet_addr("10.11.1.88");
    	toAddr.sin_port=htons(6601);
    	
    	/*Get the xmlfile and parse into string*/
        xmlDocPtr doc;      /*file descriptor of the xml*/
        xmlChar *xmlbuf;
        char *szDocName;
    	int buffersize;
    
        szDocName = argv[1];
    
        /*Open with GB2312*/
        doc = xmlReadFile(szDocName,"GB2312",XML_PARSE_RECOVER);
    	xmlDocDumpFormatMemory(doc, &xmlbuf, &buffersize, 1);
    	printf((char *) xmlbuf);
    
    	while(1)
    	{
    		sleep(1);
    
    		if(sendto(sock,xmlbuf,strlen(xmlbuf)+1,0,(struct sockaddr *)&toAddr,sizeof(toAddr)) == -1){
    			printf("Sendto failed!\n");
    			exit(2);
    			}
    	
    	printf("OK!\n");
    	}
    	close(sock);
    }

使用的xml文件：

使用*[libxml2][]*库的.c文件的编译：

gcc -o srv ser.c -I /usr/include/libxml2/ -L /usr/local/lib  -lxml2

LIBXML2的学习地址：[http://www.xmlsoft.org/html/libxml-tree.html][http_www.xmlsoft.org_html_libxml-tree.html]

[libxml2]: http://blog.csdn.net/shanzhizi/article/category/1185203
[http_www.xmlsoft.org_html_libxml-tree.html]: http://www.xmlsoft.org/html/libxml-tree.html