c++发送json格式数据（c语言发送json数据）

本文实例为大家分享了C++实现json形式的Socket传输图片的具体代码，供大家参考，具体内容如下

大致流程：客户端读取图片，经过Base64编码，转成字符串的形式，保存到json中，通过socket传到服务端，然后Base64解码，再转换成图片

一.服务端

1.main.cpp

1. #include <iostream>
2. #include <stdio.h>
3. #include "Base64_1.h"
4. #include <winsock2.h>
5. #include "json1.hpp"
7. #pragma comment(lib,"ws2_32.lib")
8. using json = nlohmann::json;
10. char revData[3888888];
12. bool WritePhotoFile(std::basic_string<TCHAR> strFileName, std::string &strData)
13. {
14. HANDLE hFile;
15. hFile = CreateFile(strFileName.c_str(), GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
17. if (hFile == INVALID_HANDLE_VALUE)
18. {
19. return false;
20. }
22. CBase64 base64;
24. int datalen(0);
25. DWORD dwritelen(0);
26. std::string strdcode = base64.Decode(strData.data(), strData.size(), datalen);
27. if (!WriteFile(hFile, strdcode.data(), datalen, &dwritelen, NULL))
28. {
29. CloseHandle(hFile);
30. return false;
31. }
32. CloseHandle(hFile);
33. return true;
34. }
36. int main(int argc, char* argv[])
37. {
38. //初始化WSA
39. WORD sockVersion = MAKEWORD(2, 2);
40. WSADATA wsaData;
41. if (WSAStartup(sockVersion, &wsaData) != 0)
42. {
43. return 0;
44. }
46. //创建套接字
47. SOCKET slisten = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
48. if (slisten == INVALID_SOCKET)
49. {
50. printf("socket error !");
51. return 0;
52. }
54. //绑定IP和端口
55. sockaddr_in sin;
56. sin.sin_family = AF_INET;
57. sin.sin_port = htons(8888);
58. sin.sin_addr.S_un.S_addr = INADDR_ANY;
60. if (bind(slisten, (LPSOCKADDR)&sin, sizeof(sin)) == SOCKET_ERROR)
61. {
62. printf("bind error !");
63. }
65. //开始监听
66. if (listen(slisten, 5) == SOCKET_ERROR)
67. {
68. printf("listen error !");
69. return 0;
70. }
72. //循环接收数据
73. SOCKET sClient;
74. sockaddr_in remoteAddr;
75. int nAddrlen = sizeof(remoteAddr);
77. //revData = (char*)malloc(sizeof(char) * 1000000);
78. int i = 1;
79. while (true)
80. {
81. printf("等待连接...\n");
82. sClient = accept(slisten, (SOCKADDR *)&remoteAddr, &nAddrlen);
83. if (sClient == INVALID_SOCKET)
84. {
85. printf("accept error !");
86. continue;
87. }
88. printf("接受到一个连接：%s \r\n", inet_ntoa(remoteAddr.sin_addr));
90. //接收数据
91. int ret = recv(sClient, revData, 3888888, 0);
92. if (ret > 0)
93. {
94. revData[ret] = 0x00;
95. json o = json::parse(revData);
96. for (json::iterator it = o.begin(); it != o.end(); ++it) {
97. //std::cout << it.key() << " : " << it.value() << "\n";
98. if (it.key() == "imgA"|| it.key() == "imgB")
99. {
100. std::string num = std::to_string(i++);
101. std::string strFileName = "D:\\"+ num +".jpg";
102. std::string val = it.value();
103. WritePhotoFile(strFileName, val);
104. }
106. }
107. //std::cout<< json::parse(revData)<< std::endl;
108. //printf(revData);
109. }
111. //发送数据
112. //const char * sendData = "你好，TCP客户端！\n";
113. //send(sClient, sendData, strlen(sendData), 0);
114. closesocket(sClient);
115. }
117. closesocket(slisten);
118. WSACleanup();
120. return 0;
121. }

2.Base64.cpp

1. #include"Base64_1.h"
3. CBase64::CBase64()
4. {
6. }
8. CBase64::~CBase64()
9. {
11. }
13. std::string CBase64::Encode(const char* Data, int DataByte)
14. {
15. //编码表
16. const char EncodeTable[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
17. //返回值
18. std::string strEncode;
19. unsigned char Tmp[4] = { 0 };
20. int LineLength = 0;
21. for (int i = 0; i<(int)(DataByte / 3); i++)
22. {
23. Tmp[1] = *Data++;
24. Tmp[2] = *Data++;
25. Tmp[3] = *Data++;
26. strEncode += EncodeTable[Tmp[1] >> 2];
27. strEncode += EncodeTable[((Tmp[1] << 4) | (Tmp[2] >> 4)) & 0x3F];
28. strEncode += EncodeTable[((Tmp[2] << 2) | (Tmp[3] >> 6)) & 0x3F];
29. strEncode += EncodeTable[Tmp[3] & 0x3F];
30. if (LineLength += 4, LineLength == 76) { strEncode += "\r\n"; LineLength = 0; }
31. }
32. //对剩余数据进行编码
33. int Mod = DataByte % 3;
34. if (Mod == 1)
35. {
36. Tmp[1] = *Data++;
37. strEncode += EncodeTable[(Tmp[1] & 0xFC) >> 2];
38. strEncode += EncodeTable[((Tmp[1] & 0x03) << 4)];
39. strEncode += "==";
40. }
41. else if (Mod == 2)
42. {
43. Tmp[1] = *Data++;
44. Tmp[2] = *Data++;
45. strEncode += EncodeTable[(Tmp[1] & 0xFC) >> 2];
46. strEncode += EncodeTable[((Tmp[1] & 0x03) << 4) | ((Tmp[2] & 0xF0) >> 4)];
47. strEncode += EncodeTable[((Tmp[2] & 0x0F) << 2)];
48. strEncode += "=";
49. }
51. return strEncode;
52. }
54. std::string CBase64::Decode(const char* Data, int DataByte, int& OutByte)
55. {
56. //解码表
57. const char DecodeTable[] =
58. {
59. 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
60. 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
61. 62, // '+'
62. 0, 0, 0,
63. 63, // '/'
64. 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, // '0'-'9'
65. 0, 0, 0, 0, 0, 0, 0,
66. 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
67. 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, // 'A'-'Z'
68. 0, 0, 0, 0, 0, 0,
69. 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38,
70. 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, // 'a'-'z'
71. };
72. //返回值
73. std::string strDecode;
74. int nValue;
75. int i = 0;
76. while (i < DataByte)
77. {
78. if (*Data != '\r' && *Data != '\n')
79. {
80. nValue = DecodeTable[*Data++] << 18;
81. nValue += DecodeTable[*Data++] << 12;
82. strDecode += (nValue & 0x00FF0000) >> 16;
83. OutByte++;
84. if (*Data != '=')
85. {
86. nValue += DecodeTable[*Data++] << 6;
87. strDecode += (nValue & 0x0000FF00) >> 8;
88. OutByte++;
89. if (*Data != '=')
90. {
91. nValue += DecodeTable[*Data++];
92. strDecode += nValue & 0x000000FF;
93. OutByte++;
94. }
95. }
96. i += 4;
97. }
98. else// 回车换行,跳过
99. {
100. Data++;
101. i++;
102. }
103. }
104. return strDecode;
105. }

3.Base64_1.h

1. //++Base64.h
3. #pragma once
4. #include <string>
6. class CBase64
7. {
8. public:
9. public:
10. CBase64();
11. ~CBase64();
13. /*编码
14. DataByte
15. [in]输入的数据长度,以字节为单位
16. */
17. std::string Encode(const char* Data, int DataByte);
19. /*解码
20. DataByte
21. [in]输入的数据长度,以字节为单位
22. OutByte
23. [out]输出的数据长度,以字节为单位,请不要通过返回值计算
24. 输出数据的长度
25. */
26. std::string Decode(const char* Data, int DataByte, int& OutByte);
28. };

4.json.hpp 去网上下载吧，个人感觉比jsoncpp好用一些（我里面的json1.hpp就是json.hpp）

二.客户端

1.main.cpp

1. #include<WINSOCK2.H>
2. #include<STDIO.H>
3. #include<iostream>
4. #include<cstring>
5. #include <string>
6. #include <fstream>
7. #include "Bash64.h"
8. #include "json1.hpp"
10. using namespace std;
11. using json = nlohmann::json;
12. #pragma comment(lib, "ws2_32.lib")
14. char chBuf1[3888888], chBuf2[3888888];
16. int main()
17. {
19. FILE *fIn1, *fIn2;
20. int nRead1, nRead2;
22. WORD sockVersion = MAKEWORD(2, 2);
23. WSADATA data;
24. if (WSAStartup(sockVersion, &data) != 0)
25. {
26. return 0;
27. }
29. std::string num = std::to_string(1);
30. std::string chFileIn1 = "E:\\"+num+".jpg";
31. num = std::to_string(2);
32. std::string chFileIn2 = "E:\\" + num + ".jpg";
34. SOCKET sclient = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
35. if (sclient == INVALID_SOCKET)
36. {
37. printf("invalid socket!");
38. return 0;
39. }
41. sockaddr_in serAddr;
42. serAddr.sin_family = AF_INET;
43. serAddr.sin_port = htons(8888);
44. serAddr.sin_addr.S_un.S_addr = inet_addr("192.168.3.72");
45. if (connect(sclient, (sockaddr *)&serAddr, sizeof(serAddr)) == SOCKET_ERROR)
46. { //连接失败
47. printf("connect error !");
48. closesocket(sclient);
49. return 0;
50. }
52. char chFileIn3[100], chFileIn4[100];
53. strcpy(chFileIn3, chFileIn1.c_str());
54. strcpy(chFileIn4, chFileIn2.c_str());
55. fIn1 = fopen(chFileIn3, "rb");
56. fIn2 = fopen(chFileIn4, "rb");
57. if (fIn1 == NULL || fIn2 == NULL)
58. {
59. printf("打开读取文件失败");
60. return 0;
61. }
62. //读文件
63. json data1;
65. //fread()读取成功返回值为实际读回的数据个数(单位为Byte)
66. nRead1 = fread(chBuf1, sizeof(char), 3888888, fIn1);
67. nRead2 = fread(chBuf2, sizeof(char), 3888888, fIn2);
68. //base64编码 封装进json
69. string imgBase64_1 = base64_encode(chBuf1, nRead1);
70. string imgBase64_2 = base64_encode(chBuf2, nRead2);
71. data1["imgA"] = imgBase64_1;
72. data1["imgB"] = imgBase64_2;
73. fclose(fIn1);
74. fclose(fIn2);
76. //显式转换为string
77. std::string s = data1.dump();
78. const char * sendData;
79. sendData = s.c_str(); //string转const char*
80. //char * sendData = "你好，TCP服务端，我是客户端\n";
81. send(sclient, sendData, strlen(sendData), 0);
83. //send()用来将数据由指定的socket传给对方主机
84. //int send(int s, const void * msg, int len, unsigned int flags)
85. //s为已建立好连接的socket，msg指向数据内容，len则为数据长度，参数flags一般设0
86. //成功则返回实际传送出去的字符数，失败返回-1，错误原因存于error
88. char recData[266680];
89. int ret = recv(sclient, recData, 266680, 0);
90. if (ret>0) {
91. recData[ret] = 0x00;
92. //printf(recData);
93. }
94. closesocket(sclient);
96. WSACleanup();
97. system("pause");
98. return 0;
100. }

2.Bash64.h

1. #ifndef __BASE64_H__
2. #define __BASE64_H__
4. #include <iostream>
5. #include <string>
7. static const std::string base64_chars =
8. "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
9. "abcdefghijklmnopqrstuvwxyz"
10. "0123456789+/";
12. static inline bool is_base64(const char c)
13. {
14. return (isalnum(c) || (c == '+') || (c == '/'));
15. }
17. std::string base64_encode(const char * bytes_to_encode, unsigned int in_len)
18. {
19. std::string ret;
20. int i = 0;
21. int j = 0;
22. unsigned char char_array_3[3];
23. unsigned char char_array_4[4];
25. while (in_len--)
26. {
27. char_array_3[i++] = *(bytes_to_encode++);
28. if (i == 3)
29. {
30. char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
31. char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
32. char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
33. char_array_4[3] = char_array_3[2] & 0x3f;
34. for (i = 0; (i <4); i++)
35. {
36. ret += base64_chars[char_array_4[i]];
37. }
38. i = 0;
39. }
40. }
41. if (i)
42. {
43. for (j = i; j < 3; j++)
44. {
45. char_array_3[j] = '\0';
46. }
48. char_array_4[0] = (char_array_3[0] & 0xfc) >> 2;
49. char_array_4[1] = ((char_array_3[0] & 0x03) << 4) + ((char_array_3[1] & 0xf0) >> 4);
50. char_array_4[2] = ((char_array_3[1] & 0x0f) << 2) + ((char_array_3[2] & 0xc0) >> 6);
51. char_array_4[3] = char_array_3[2] & 0x3f;
53. for (j = 0; (j < i + 1); j++)
54. {
55. ret += base64_chars[char_array_4[j]];
56. }
58. while ((i++ < 3))
59. {
60. ret += '=';
61. }
63. }
64. return ret;
65. }
67. std::string base64_decode(std::string const & encoded_string)
68. {
69. int in_len = (int)encoded_string.size();
70. int i = 0;
71. int j = 0;
72. int in_ = 0;
73. unsigned char char_array_4[4], char_array_3[3];
74. std::string ret;
76. while (in_len-- && (encoded_string[in_] != '=') && is_base64(encoded_string[in_])) {
77. char_array_4[i++] = encoded_string[in_]; in_++;
78. if (i == 4) {
79. for (i = 0; i <4; i++)
80. char_array_4[i] = base64_chars.find(char_array_4[i]);
82. char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
83. char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
84. char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];
86. for (i = 0; (i < 3); i++)
87. ret += char_array_3[i];
88. i = 0;
89. }
90. }
91. if (i) {
92. for (j = i; j <4; j++)
93. char_array_4[j] = 0;
95. for (j = 0; j <4; j++)
96. char_array_4[j] = base64_chars.find(char_array_4[j]);
98. char_array_3[0] = (char_array_4[0] << 2) + ((char_array_4[1] & 0x30) >> 4);
99. char_array_3[1] = ((char_array_4[1] & 0xf) << 4) + ((char_array_4[2] & 0x3c) >> 2);
100. char_array_3[2] = ((char_array_4[2] & 0x3) << 6) + char_array_4[3];
102. for (j = 0; (j < i - 1); j++) ret += char_array_3[j];
103. }
105. return ret;
106. }
107. #endif

3.json.hpp 上面有链接（我里面的json1.hpp就是json.hpp）

Hit:服务端和客户端的Base64文件不一样，是因为当时服务端接收json时，Base64解码成图片出现了问题，又去找大神的博客，把服务端的Base64文件换了。然后能进行正常的传输图片，客户端就懒得换了~

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我们。

原文链接：https://blog.csdn.net/weixin_42755375/article/details/81590967

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