java上传文件到微信服务器

 package com.sz.kcygl.common.util;

 import java.io.BufferedReader;
 import java.io.DataInputStream;
 import java.io.DataOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.io.OutputStream;
 import java.net.HttpURLConnection;
 import java.net.URL;

 import net.sf.json.JSONArray;
 import net.sf.json.JSONObject;

 public class FileUpload {

     /**
     * 模拟form表单的形式 ，上传文件 以输出流的形式把文件写入到url中，然后用输入流来获取url的响应
     *
     * @param url 请求地址 form表单url地址
     * @param filePath 文件在服务器保存路径
     * @return String url的响应信息返回值
     * @throws IOException
     */
     public static String send(String url, String filePath) throws IOException {


     String result = null;


     File file = new File(filePath);
     if (!file.exists() || !file.isFile()) {
     throw new IOException("文件不存在");
     }


     /**
     * 第一部分
     */
     URL urlObj = new URL(url);
     // 连接
     HttpURLConnection con = (HttpURLConnection) urlObj.openConnection();


     /**
     * 设置关键值
     */
     con.setRequestMethod("POST"); // 以Post方式提交表单，默认get方式
     con.setDoInput(true);
     con.setDoOutput(true);
     con.setUseCaches(false); // post方式不能使用缓存


     // 设置请求头信息
     con.setRequestProperty("Connection", "Keep-Alive");
     con.setRequestProperty("Charset", "UTF-8");


     // 设置边界
     String BOUNDARY = "----------" + System.currentTimeMillis();
     con.setRequestProperty("Content-Type", "multipart/form-data; boundary="+ BOUNDARY);


     // 请求正文信息


     // 第一部分：
     StringBuilder sb = new StringBuilder();
     sb.append("--"); // 必须多两道线
     sb.append(BOUNDARY);
     sb.append("\r\n");
     sb.append("Content-Disposition: form-data;name=\"file\";filename=\""
     + file.getName() + "\"\r\n");
     sb.append("Content-Type:application/octet-stream\r\n\r\n");


     byte[] head = sb.toString().getBytes("utf-8");


     // 获得输出流
     OutputStream out = new DataOutputStream(con.getOutputStream());
     // 输出表头
     out.write(head);


     // 文件正文部分
     // 把文件已流文件的方式 推入到url中
     DataInputStream in = new DataInputStream(new FileInputStream(file));
     int bytes = 0;
     byte[] bufferOut = new byte[1024];
     while ((bytes = in.read(bufferOut)) != -1) {
     out.write(bufferOut, 0, bytes);
     }
     in.close();


     // 结尾部分
     byte[] foot = ("\r\n--" + BOUNDARY + "--\r\n").getBytes("utf-8");// 定义最后数据分隔线


     out.write(foot);


     out.flush();
     out.close();


     StringBuffer buffer = new StringBuffer();
     BufferedReader reader = null;
     try {
     // 定义BufferedReader输入流来读取URL的响应
     reader = new BufferedReader(new InputStreamReader(con.getInputStream()));
     String line = null;
     while ((line = reader.readLine()) != null) {
     //System.out.println(line);
     buffer.append(line);
     }
     if(result==null){
     result = buffer.toString();
     }
     } catch (IOException e) {
     System.out.println("发送POST请求出现异常！" + e);
     e.printStackTrace();
     throw new IOException("数据读取异常");
     } finally {
     if(reader!=null){
     reader.close();
     }

     }

     JSONObject jsonObj = JSONObject.fromObject(result);
     String mediaId = jsonObj.getString("media_id");
     return mediaId;
     }


     public static void main(String[] args) throws IOException {
     String filePath = "D:/tomcat/apache-tomcat-6.0.37/webapps/Allianture_frame/upload/test3_20140117094014814.jpg";
     String sendUrl = "http://file.api.weixin.qq.com/cgi-bin/media/upload?access_token=yeQEu_OrXQanGC_G56BZ7IKJDCQCaO0ryDWKX2N2JDzGRGuiZACTGjsQXW-S-K1fgm_MViG_R5AwIEBhKKCNmUevg0H3ksfzlIfkFcP1y8g2st2LYwloL_iPqhedlT5_Z1zSM2mZSmu6cI54sayMPw&type=image";
     String result = null;
     FileUpload fileUpload = new FileUpload();
     result = fileUpload.send(sendUrl, filePath);
     System.out.println(result);

     }
 }