一、概述

    本人是用C#编程，调用百度API接口实现手写体识别的，参考了百度的产品文档。文档地址：https://cloud.baidu.com/doc/OCR/index.html

二、代码及解说

本人的源代码大部分是来自百度的产品文档，但其中也遇到了一些麻烦。比如文字识别的编码问题，百度的代码给出的编码是Default，但在我的机器上这样做会显示乱码。经过查找资料，我把编码改成UTF8，乱码的问题才得到解决。

作者的所有源代码如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Net.Http;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System.IO;
using System.Drawing;
using System.Web;
using System.Net;

namespace myHandwrite
{
    public static class FileUtils
    {
        /// 
        /// 转base64编码
        /// 
        /// 
        /// 
        public static String getFileBase64(String fileName)
        {
            FileStream filestream = new FileStream(fileName, FileMode.Open);
            byte[] arr = new byte[filestream.Length];
            filestream.Read(arr, 0, (int)filestream.Length);
            string baser64 = Convert.ToBase64String(arr);
            filestream.Close();
            return baser64;
        }
    }
    class Program
    {
        // 调用getAccessToken()获取的 access_token建议根据expires_in 时间 设置缓存
        // 返回token示例
        public static String TOKEN = "24.adda70c11b9786206253ddb70affdc46.2592000.1493524354.282335-1234567";

        // 百度云中开通对应服务应用的 API Key 建议开通应用的时候多选服务
        private static String clientId = "这里改成你的API Key";
        // 百度云中开通对应服务应用的 Secret Key
        private static String clientSecret = "这里改成你的Secret Key";
        /// 
        /// 获取token的函数
        /// 
        /// 
        public static String getAccessToken()
        {
            String authHost = "https://aip.baidubce.com/oauth/2.0/token";
            HttpClient client = new HttpClient();
            List> paraList = new List>();
            paraList.Add(new KeyValuePair("grant_type", "client_credentials"));
            paraList.Add(new KeyValuePair("client_id", clientId));
            paraList.Add(new KeyValuePair("client_secret", clientSecret));

            HttpResponseMessage response = client.PostAsync(authHost, new FormUrlEncodedContent(paraList)).Result;
            String result = response.Content.ReadAsStringAsync().Result;
            //Console.WriteLine(result);
            //自己加的代码
            JObject jo = (JObject)JsonConvert.DeserializeObject(result.ToString());
            string myToken = jo["access_token"].ToString();
            Console.WriteLine("获得的Token是：" + myToken);
            return myToken;
        }
        
        /// 
        /// 手写体文字识别
        /// 
        /// 
        /// 
        /// 
        public static string myHandwriting(string token,string filename)
        {
            //string token = "#####调用鉴权接口获取的token#####";
            // 图片的base64编码
            string strbaser64 = FileUtils.getFileBase64(filename); 
            string host = "https://aip.baidubce.com/rest/2.0/ocr/v1/handwriting?access_token=" + token;
            Encoding encoding = Encoding.Default;
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(host);
            request.Method = "post";
            request.ContentType = "application/x-www-form-urlencoded";
            request.KeepAlive = true;
            //这里加上了一些参数
            String str = "recognize_granularity=big&image=" + HttpUtility.UrlEncode(strbaser64);
            byte[] buffer = encoding.GetBytes(str);
            request.ContentLength = buffer.Length;
            request.GetRequestStream().Write(buffer, 0, buffer.Length);
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            //显示结果是乱码，尝试改变编码，经过测试需要改成UTF8编码
            StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8);
            string result = reader.ReadToEnd();
            Console.WriteLine("手写文字识别:");
            //Console.WriteLine(result);
            //解析Json的代码
            JObject jo = (JObject)JsonConvert.DeserializeObject(result.ToString());
            int num = (int)jo["words_result_num"];
            string[] words = new string[num];
            for (int i = 0; i < num; i++)
                words[i] = jo["words_result"][i]["words"].ToString();
            //返回值
            string txtOCR = null;
            for (int i = 0; i < num; i++)
                txtOCR += words[i] + "\n";
            //显示结果
            Console.WriteLine(txtOCR);
            return txtOCR;
        }
        static void Main(string[] args)
        {
            //这里要改成你的图片路径
            string filename = @"F:\手写体5.jpg";
            string token = getAccessToken();
            myHandwriting(token,filename);
            Console.Read();
        }
    }
}

注意，上面的代码中需要各位改成自己的Akey和Skey，另外要改一下图片路径。如果返回的是乱码，还需要改一下编码。

识别的结果如下：

程序用的图片文件如下：