微信公众号 IOS 流文件 微信公众号插文件

公众号在使用接口时，对多媒体文件、多媒体消息的获取和调用等操作，是通过media_id来进行的。通过本接口，公众号可以上传或下载多媒体文件。但请注意，每个多媒体文件（media_id）会在上传、用户发送到微信服务器3天后自动删除，以节省服务器资源。

公众号可调用本接口来上传图片、语音、视频等文件到微信服务器，上传后服务器会返回对应的media_id，公众号此后可根据该media_id来获取多媒体。请注意，media_id是可复用的，调用该接口需http协议。

接口调用请求说明

http请求方式: POST/FORM
http://file.api.weixin.qq.com/cgi-bin/media/upload?access_token=ACCESS_TOKEN&type=TYPE
调用示例（使用curl命令，用FORM表单方式上传一个多媒体文件）：
curl -F media=@test.jpg "http://file.api.weixin.qq.com/cgi-bin/media/upload?access_token=ACCESS_TOKEN&type=TYPE"

首先封装一个HttpPostUtil类，专门负责文件上传请求及一些参数的设置(此处可以理解为上传文件表单参数设置和connection的一些必须设置)、字符编码，文件类型等。

HttpPostUtil类代码：

import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Set;

/**
 * 
 * @author Sunlight
 * 
 */
public class HttpPostUtil {
	private URL url;
	private HttpURLConnection conn;
	private String boundary = "--------httppost123";
	private HashMap<String, String> textParams = new HashMap<String, String>();
	private HashMap<String, File> fileparams = new HashMap<String, File>();
	private DataOutputStream outputStream;

	public HttpPostUtil(String url) throws Exception {
		this.url = new URL(url);
	}

	/**
	 * 重新设置要请求的服务器地址，即上传文件的地址。
	 * 
	 * @param url
	 * @throws Exception
	 */
	public void setUrl(String url) throws Exception {
		this.url = new URL(url);
	}

	/**
	 * 增加一个普通字符串数据到form表单数据中
	 * 
	 * @param name
	 * @param value
	 */
	public void addParameter(String name, String value) {
		textParams.put(name, value);
	}

	/**
	 * 增加一个文件到form表单数据中
	 * 
	 * @param name
	 * @param value
	 */
	public void addParameter(String name, File value) {
		fileparams.put(name, value);
	}

	/**
	 * 清空所有已添加的form表单数据
	 */
	public void clearAllParameters() {
		textParams.clear();
		fileparams.clear();
	}

	/**
	 * 发送数据到服务器，返回一个字节包含服务器的返回结果的数组
	 * 
	 * @return
	 * @throws Exception
	 */
	public String send() throws Exception {
		initConnection();
		conn.connect();
		outputStream = new DataOutputStream(conn.getOutputStream());
		writeFileParams();
		writeStringParams();
		paramsEnd();
		int code = conn.getResponseCode();
		if (code == 200) {
			InputStream in = conn.getInputStream();
			ByteArrayOutputStream out = new ByteArrayOutputStream();
			byte[] buf = new byte[1024 * 8];
			int len;
			while ((len = in.read(buf)) != -1) {
				out.write(buf, 0, len);
			}
			conn.disconnect();
			String s = new String(out.toByteArray(), "utf-8");
			return s;
		}
		return null;
	}

	/**
	 * 文件上传的connection的一些必须设置
	 * 
	 * @throws Exception
	 */
	private void initConnection() throws Exception {
		conn = (HttpURLConnection) this.url.openConnection();
		conn.setDoOutput(true);
		conn.setUseCaches(false);
		conn.setConnectTimeout(10000); // 连接超时为10秒
		conn.setRequestMethod("POST");
		conn.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + boundary);
	}

	/**
	 * 普通字符串数据
	 * 
	 * @throws Exception
	 */
	private void writeStringParams() throws Exception {
		Set<String> keySet = textParams.keySet();
		for (Iterator<String> it = keySet.iterator(); it.hasNext();) {
			String name = it.next();
			String value = textParams.get(name);
			outputStream.writeBytes("--" + boundary + "\r\n");
			outputStream.writeBytes("Content-Disposition: form-data; name=\"" + name + "\"\r\n");
			outputStream.writeBytes("\r\n");
			outputStream.writeBytes(encode(value) + "\r\n");
		}
	}

	/**
	 * 文件数据
	 * 
	 * @throws Exception
	 */
	private void writeFileParams() throws Exception {
		Set<String> keySet = fileparams.keySet();
		for (Iterator<String> it = keySet.iterator(); it.hasNext();) {
			String name = it.next();
			File value = fileparams.get(name);
			outputStream.writeBytes("--" + boundary + "\r\n");
			outputStream.writeBytes("Content-Disposition: form-data; name=\"" + name + "\"; filename=\"" + encode(value.getName()) + "\"\r\n");
			outputStream.writeBytes("Content-Type: " + getContentType(value) + "\r\n");
			outputStream.writeBytes("\r\n");
			outputStream.write(getBytes(value));
			outputStream.writeBytes("\r\n");
		}
	}

	/**
	 * 获取文件的上传类型，图片格式为image/png,image/jpeg等。非图片为application /octet-stream
	 * 
	 * @param f
	 * @return
	 * @throws Exception
	 */
	private String getContentType(File f) throws Exception {
		return "application/octet-stream";
	}

	/**
	 * 把文件转换成字节数组
	 * 
	 * @param f
	 * @return
	 * @throws Exception
	 */
	private byte[] getBytes(File f) throws Exception {
		FileInputStream in = new FileInputStream(f);
		ByteArrayOutputStream out = new ByteArrayOutputStream();
		byte[] b = new byte[1024];
		int n;
		while ((n = in.read(b)) != -1) {
			out.write(b, 0, n);
		}
		in.close();
		return out.toByteArray();
	}

	/**
	 * 添加结尾数据
	 * 
	 * @throws Exception
	 */
	private void paramsEnd() throws Exception {
		outputStream.writeBytes("--" + boundary + "--" + "\r\n");
		outputStream.writeBytes("\r\n");
	}

	/**
	 * 对包含中文的字符串进行转码，此为UTF-8。服务器那边要进行一次解码
	 * 
	 * @param value
	 * @return
	 * @throws Exception
	 */
	private String encode(String value) throws Exception {
		return URLEncoder.encode(value, "UTF-8");
	}	
}

上传测试方法（可以在自己项目中上传文件到一些第三方提供的平台）：

/**
 * 使用方法示例
 * 此方法需要修改成自己上传地址才可上传成功
 * @param args
 * @throws Exception
 */
public static void test(String[] args) throws Exception {
	File file=new File("D\\up.jpg");
	//此处修改为自己上传文件的地址
	HttpPostUtil post = new HttpPostUtil("http://www.omsdn.cn"); 
	//此处参数类似 curl -F media=@test.jpg
	post.addParameter("media", file);
	post.send();
}

上传文件方法封装好后，微信公众号上传文件类调用,此处需要JSON包（json-lib-2.2.3-jdk13.jar）：

import java.io.File;
import cn.<span style="font-family:FangSong_GB2312;">xx</span>.wechat.model.MdlUpload;
import cn.<span style="font-family:FangSong_GB2312;">xx</span>.wechat.model.Result;
import net.sf.json.JSONObject;
/**
 * 
 * @author Sunlight
 *
 */
public class FileUpload {
    private static final String upload_url = "https://qyapi.weixin.qq.com/cgi-bin/media/upload?access_token=ACCESS_TOKEN&type=TYPE";
    
    /**
     * 上传文件
     * 
     * @param accessToken
     * @param type
     * @param file
     * @return
     */
    public static Result<MdlUpload> Upload(String accessToken, String type, File file) {
        Result<MdlUpload> result = new Result<MdlUpload>();
        String url = upload_url.replace("ACCESS_TOKEN", accessToken).replace("TYPE", type);
        JSONObject jsonObject;
        try {
            HttpPostUtil post = new HttpPostUtil(url);
            post.addParameter("media", file);
            String s = post.send();
            jsonObject = JSONObject.fromObject(s);
            if (jsonObject.containsKey("media_id")) {
                MdlUpload upload=new MdlUpload();
                upload.setMedia_id(jsonObject.getString("media_id"));
                upload.setType(jsonObject.getString("type"));
                upload.setCreated_at(jsonObject.getString("created_at"));
                result.setObj(upload);
                result.setErrmsg("success");
                result.setErrcode("0");
            } else {
                result.setErrmsg(jsonObject.getString("errmsg"));
                result.setErrcode(jsonObject.getString("errcode"));
            }
        } catch (Exception e) {
            e.printStackTrace();
            result.setErrmsg("Upload Exception:"+e.toString());
        }
        return result;
    }
}

调用方法需要引用2个Model类（返回结果类和上传文件类型类）：

返回结果类：

package cn.<span style="font-family:FangSong_GB2312;">xx</span>.wechat.model;

public class Result<T> {
	private T obj;
	private String errcode;
	private String errmsg;
	public T getObj() {
		return obj;
	}
	public void setObj(T obj) {
		this.obj = obj;
	}
<span style="font-family:FangSong_GB2312;">        </span>public String getErrcode() {
		return errcode;
	}
	 public void setErrcode(String errcode) {
		 this.errcode = errcode;
	 }
 	public String getErrmsg() {
		 return errmsg;
 	}
 	public void setErrmsg(String errmsg) {
		 this.errmsg = errmsg;
 	}
	
}

文件上传返回文件类型类：

package cn.<span style="font-family:FangSong_GB2312;">xx</span>.wechat.model;

public class MdlUpload {
 	private String type;
	private String media_id;
	private String created_at;
  	public String getType() {
  		return type;
	}
	  public void setType(String type) {
		 this.type = type;
	  }
 	public String getMedia_id() {
		  return media_id;
  	}
	 public void setMedia_id(String mediaId) {
		  media_id = mediaId;
  	}
 	public String getCreated_at() {
		  return created_at;
	  }
	 public void setCreated_at(String createdAt) {
		  created_at = createdAt;
 	}
	  public MdlUpload() {
		 super();
	 }
	@Override
	public String toString() {
 		return "MdlUpload [created_at=" + created_at + ", media_id=" + media_id + ", type=" + type + "]";
	 }
	
	
}

最后微信上传文件测试方法：

@Test
    public void testUpload() {
        File file=new File("E:\\Tulips.jpg");
        System.err.println(file.getName());
        Result<MdlUpload> result=FileUpload .Upload("image", file);
        System.out.println("Errcode="+result.getErrcode()+"\tErrmsg="+result.getErrmsg());
        System.out.println(result.getObj().toString());
    }

测试结果：